View
226
Download
0
Category
Tags:
Preview:
Citation preview
Remote procedure call - Message passing
1 An RPC is initiated by the client, which sends a request message to a known remote server to execute a specified procedure with supplied
parameters
https://store.theartofservice.com/the-message-passing-toolkit.html
Remote procedure call - Message passing
1 An important difference between remote procedure calls and local calls is that remote
calls can fail because of unpredictable network problems. Also, callers generally must deal with
such failures without knowing whether the remote procedure was actually invoked.
Idempotent procedures (those that have no additional effects if called more than once) are easily handled, but enough difficulties remain that code to call remote procedures is often
confined to carefully written low-level subsystems.
https://store.theartofservice.com/the-message-passing-toolkit.html
Message passing
1 Message passing in computer science is a form of communication used in concurrent
computing, parallel computing, object-oriented programming, and interprocess
communication. In this model, processes or objects can send and receive messages (comprising zero or more bytes, complex
data structures, or even segments of code) to other processes. By waiting for
messages, processes can also synchronize.
https://store.theartofservice.com/the-message-passing-toolkit.html
Message passing - Overview
1 Message passing is the paradigm of communication where messages are sent from a sender to one or more
recipients. Forms of messages include (remote) method invocation,
signals, and data packets. When designing a message passing system
several choices are made:
https://store.theartofservice.com/the-message-passing-toolkit.html
Message passing - Overview
1 Whether messages are guaranteed to be delivered in
order
https://store.theartofservice.com/the-message-passing-toolkit.html
Message passing - Overview
1 Whether messages are passed one-to-one (unicast), one-to-many
(multicast or broadcast), many-to-one (client–server), or many-to-many
(All-to-All).
https://store.theartofservice.com/the-message-passing-toolkit.html
Message passing - Overview
1 Whether communication is synchronous or
asynchronous.
https://store.theartofservice.com/the-message-passing-toolkit.html
Message passing - Overview
1 Examples of the latter include Microkernel operating systems that pass messages between one kernel and one or more server blocks, and the Message Passing Interface used
in high-performance computing.
https://store.theartofservice.com/the-message-passing-toolkit.html
Message passing - Message passing systems
1 Distributed object and remote method invocation systems like ONC
RPC, CORBA, Java RMI, DCOM, SOAP, .NET Remoting, CTOS, QNX
Neutrino RTOS, OpenBinder, D-Bus, Unison RTOS and similar are message passing systems.
https://store.theartofservice.com/the-message-passing-toolkit.html
Message passing - Message passing systems
1 Message passing systems have been called "shared nothing" systems because the message passing
abstraction hides underlying state changes that may be used in the
implementation of sending messages.
https://store.theartofservice.com/the-message-passing-toolkit.html
Message passing - Message passing systems
1 Message passing model based programming languages typically define messaging as the (usually asynchronous) sending (usually by copy) of a data item to a communication endpoint (Actor, process, thread, socket,
etc.). Such messaging is used in Web Services by SOAP. This concept is the higher-
level version of a datagram except that messages can be larger than a packet and can optionally be made reliable, durable,
secure, and/or transacted.
https://store.theartofservice.com/the-message-passing-toolkit.html
Message passing - Message passing systems
1 Messages are also commonly used in the same sense as a means of
interprocess communication; the other common technique being
streams or pipes, in which data are sent as a sequence of elementary
data items instead (the higher-level version of a virtual circuit).
https://store.theartofservice.com/the-message-passing-toolkit.html
Message passing - Synchronous versus asynchronous message passing
1 Synchronous message passing systems require the sender and receiver to wait for each other to transfer the message. That is, the sender will not continue until the
receiver has received the message.
https://store.theartofservice.com/the-message-passing-toolkit.html
Message passing - Synchronous versus asynchronous message passing
1 Synchronous communication has two advantages. The first advantage is that
reasoning about the program can be simplified in that there is a
synchronisation point between sender and receiver on message transfer. The second advantage is that no buffering is required. The message can always be stored on the receiving side, because the sender will not
continue until the receiver is ready.
https://store.theartofservice.com/the-message-passing-toolkit.html
Message passing - Synchronous versus asynchronous message passing
1 Asynchronous message passing systems deliver a message from
sender to receiver, without waiting for the receiver to be ready. The
advantage of asynchronous communication is that the sender
and receiver can overlap their computation because they do not
wait for each other.
https://store.theartofservice.com/the-message-passing-toolkit.html
Message passing - Synchronous versus asynchronous message passing
1 Synchronous communication can be built on top of asynchronous
communication by using a so-called Synchronizer. For example, the α-
Synchronizer works by ensuring that the sender always waits for an
acknowledgement message from the receiver. The sender only sends the
next message after the acknowledgement has been
received.https://store.theartofservice.com/the-message-passing-toolkit.html
Message passing - Synchronous versus asynchronous message passing
1 The buffer required in asynchronous communication can cause problems when it is full. A decision has to be
made whether to block the sender or whether to discard future messages. If the sender is blocked, it may lead
to an unexpected deadlock. If messages are dropped, then
communication is no longer reliable.
https://store.theartofservice.com/the-message-passing-toolkit.html
Message passing - Message passing versus calling
1 Message passing should be contrasted with the alternative communication method for passing information between programs –
the Call. In a traditional Call, arguments are passed to the "callee" (the receiver)
typically by one or more general purpose registers or in a parameter list containing the addresses of each of the arguments. This form of communication differs from message passing in at least three crucial
areas:https://store.theartofservice.com/the-message-passing-toolkit.html
Message passing - Message passing versus calling
1 In message passing, each of the arguments has to have sufficient available extra memory
for copying the existing argument into a portion of the new message. This applies
irrespective of the size of the original arguments – so if one of the arguments is
(say) an HTML string of 31,000 octets describing a web page (similar to the size of this article), it has to be copied in its entirety
(and perhaps even transmitted) to the receiving program (if not a local program).
https://store.theartofservice.com/the-message-passing-toolkit.html
Message passing - Message passing versus calling
1 Web browsers and web servers are examples of processes that communicate by message
passing
https://store.theartofservice.com/the-message-passing-toolkit.html
Message passing - Message passing versus calling
1 A subroutine call or method invocation will not exit until the
invoked computation has terminated. Asynchronous message passing, by contrast, can result in a response
arriving a significant time after the request message was sent.
https://store.theartofservice.com/the-message-passing-toolkit.html
Message passing - Message passing versus calling
1 A message handler will, in general, process messages from more than one sender. This
means its state can change for reasons unrelated to the behaviour of a single sender
or client process. This is in contrast to the typical behaviour of an object upon which methods are being invoked: the latter is expected to remain in the same state
between method invocations. In other words, the message handler behaves analogously
to a volatile object.
https://store.theartofservice.com/the-message-passing-toolkit.html
Message passing - Message passing and locks
1 Message passing can be used as a way of controlling access to resources in a concurrent or
asynchronous system. One of the main alternatives is mutual exclusion
or locking. Examples of resources include shared memory, a disk file or region thereof, a database table or
set of rows.
https://store.theartofservice.com/the-message-passing-toolkit.html
Message passing - Message passing and locks
1 In locking, a resource is essentially shared, and processes wishing to
access it (or a sector of it) must first obtain a lock. Once the lock is acquired, other processes are
blocked out, ensuring that corruption from simultaneous writes does not
occur. After the process with the lock is finished with the resource, the lock
is then released.https://store.theartofservice.com/the-message-passing-toolkit.html
Message passing - Message passing and locks
1 With the message-passing solution, it is assumed that the resource is not exposed, and all changes to it are made by an associated process, so that the resource is encapsulated
https://store.theartofservice.com/the-message-passing-toolkit.html
Message passing - Mathematical models
1 The prominent mathematical models of message passing are the Actor model and Pi
calculus.
https://store.theartofservice.com/the-message-passing-toolkit.html
Message passing - Mathematical models
1 In the terminology of some object-oriented programming languages, a message is the single means to pass
control to an object. If the object "responds" to the message, it has a method for that message. In pure
object-oriented programming, message passing is performed exclusively through a dynamic
dispatch strategy.https://store.theartofservice.com/the-message-passing-toolkit.html
Message passing - Mathematical models
1 Message passing enables extreme late binding in systems
https://store.theartofservice.com/the-message-passing-toolkit.html
Message passing - Mathematical models
1 Alan Kay has argued that message passing is more important than objects in OOP, and
that objects themselves are often over-emphasized. The live distributed objects
programming model builds upon this observation; it uses the concept of a
distributed data flow to characterize the behavior of a complex distributed system in terms of message patterns, using high-
level, functional-style specifications.
https://store.theartofservice.com/the-message-passing-toolkit.html
Message passing - Further reading
1 Ramachandran, U.; M. Solomon, M. Vernon (1987). "Hardware support for
interprocess communication". Proceedings of the 14th annual
international symposium on Computer architecture. ACM Press.
https://store.theartofservice.com/the-message-passing-toolkit.html
Message passing - Further reading
1 Chao, Linda (1987), "Architectural features of a message-driven
processor", Thesis (B.S.) Massachusetts Institute of
Technology, Dept. of Electrical Engineering and Computer Science
https://store.theartofservice.com/the-message-passing-toolkit.html
Message passing - Further reading
1 McQuillan, John M.; David C. Walden (1975). "Some considerations for a high performance message-based
interprocess communication system". Proceedings of the 1975 ACM
SIGCOMM/SIGOPS workshop on Interprocess communications. ACM
Press.
https://store.theartofservice.com/the-message-passing-toolkit.html
Computer cluster - Message passing and communication
1 Two widely used approaches for communication between cluster
nodes are MPI, the Message Passing Interface and PVM, the Parallel
Virtual Machine.
https://store.theartofservice.com/the-message-passing-toolkit.html
Computer cluster - Message passing and communication
1 PVM was developed at the Oak Ridge National Laboratory around 1989
before MPI was available. PVM must be directly installed on every cluster node and provides a set of software
libraries that paint the node as a "parallel virtual machine". PVM
provides a run-time environment for message-passing, task and resource management, and fault notification. PVM can be used by user programs written in C, C++, or Fortran, etc.
https://store.theartofservice.com/the-message-passing-toolkit.html
Computer cluster - Message passing and communication
1 MPI emerged in the early 1990s out of discussions among 40 organizations
https://store.theartofservice.com/the-message-passing-toolkit.html
Message Passing Interface - History
1 Out of that discussion came a Workshop on Standards for Message
Passing in a Distributed Memory Environment held on April 29–30,
1992 in Williamsburg, Virginia
https://store.theartofservice.com/the-message-passing-toolkit.html
Message Passing Interface - History
1 The MPI effort involved about 80 people from 40 organizations, mainly
in the United States and Europe. Most of the major vendors of
concurrent computers were involved in MPI along with researchers from
universities, government laboratories, and industry.
https://store.theartofservice.com/the-message-passing-toolkit.html
Message Passing Interface - History
1 The MPI standard defines the syntax and semantics of a core of library routines useful to a wide range of users writing portable message
passing programs in Fortran and C.
https://store.theartofservice.com/the-message-passing-toolkit.html
Message Passing Interface - History
1 MPI provides a simple-to-use portable interface for the basic user, yet
powerful enough to allow programmers to use the high-performance message passing
operations available on advanced machines.
https://store.theartofservice.com/the-message-passing-toolkit.html
Message Passing Interface - History
1 The message passing paradigm is attractive because of wide portability and can be used in communication for distributed-memory and shared-
memory multiprocessors, networks of workstations, and a combination of
these elements
https://store.theartofservice.com/the-message-passing-toolkit.html
Message Passing Interface - History
1 Support for MPI meetings came in part from ARPA and US National
Science Foundation under grant ASC-9310330, NSF Science and
Technology Center Cooperative agreement number CCR-8809615,
and the Commission of the European Community through Esprit Project
P6643. The University of Tennessee also made financial contributions to
the MPI Forum.https://store.theartofservice.com/the-message-passing-toolkit.html
Message Passing Interface - Overview
1 MPI is a language-independent communications protocol used to program parallel computers. Both
point-to-point and collective communication are supported. MPI "is a message-passing application
programmer interface, together with protocol and semantic specifications for how its features must behave in
any implementation." MPI's goals are high performance, scalability, and
portability. MPI remains the dominant model used in high-performance
computing today.
https://store.theartofservice.com/the-message-passing-toolkit.html
Message Passing Interface - Overview
1 MPI is not sanctioned by any major standards body; nevertheless, it has
become a de facto standard for communication among processes
that model a parallel program running on a distributed memory
system
https://store.theartofservice.com/the-message-passing-toolkit.html
Message Passing Interface - Overview
1 Although MPI belongs in layers 5 and higher of the OSI Reference Model, implementations may cover most
layers, with sockets and Transmission Control Protocol (TCP) used in the
transport layer.
https://store.theartofservice.com/the-message-passing-toolkit.html
Message Passing Interface - Overview
1 Most MPI implementations consist of a specific set of routines (i.e., an API) directly callable from C, C++, Fortran and any language able to interface
with such libraries, including C#, Java or Python. The advantages of MPI
over older message passing libraries are portability (because MPI has been
implemented for almost every distributed memory architecture) and speed (because each implementation
is in principle optimized for the hardware on which it runs).
https://store.theartofservice.com/the-message-passing-toolkit.html
Message Passing Interface - Overview
1 MPI uses Language Independent Specifications (LIS) for calls and language bindings. The first MPI standard specified ANSI C and
Fortran-77 bindings together with the LIS. The draft was presented at
Supercomputing 1994 (November 1994) and finalized soon thereafter. About 128 functions constitute the
MPI-1.3 standard which was released as the final end of the MPI-1 series in
2008.
https://store.theartofservice.com/the-message-passing-toolkit.html
Message Passing Interface - Overview
1 Object interoperability was also added to allow easier mixed-language message
passing programming
https://store.theartofservice.com/the-message-passing-toolkit.html
Message Passing Interface - Overview
1 MPI-2 is mostly a superset of MPI-1, although some functions have been deprecated. MPI-1.3 programs still work under MPI implementations
compliant with the MPI-2 standard.
https://store.theartofservice.com/the-message-passing-toolkit.html
Message Passing Interface - Overview
1 Threaded shared memory programming models (such as
Pthreads and OpenMP) and message passing programming (MPI/PVM) can
be considered as complementary programming approaches, and can
occasionally be seen together in applications, e.g
https://store.theartofservice.com/the-message-passing-toolkit.html
Message Passing Interface - Functionality
1 The MPI interface is meant to provide essential virtual topology,
synchronization, and communication functionality between a set of
processes (that have been mapped to nodes/servers/computer instances) in a language-
independent way, with language-specific syntax (bindings), plus a few
language-specific featureshttps://store.theartofservice.com/the-message-passing-toolkit.html
Message Passing Interface - Functionality
1 MPI library functions include, but are not limited to, point-to-point rendezvous-type send/receive
operations, choosing between a Cartesian or graph-like logical process topology, exchanging data
between process pairs (send/receive operations), combining partial results of computations (gather
and reduce operations), synchronizing nodes (barrier operation) as well as obtaining network-
related information such as the number of processes in the computing session, current processor identity that a process is mapped to, neighboring processes
accessible in a logical topology, and so on
https://store.theartofservice.com/the-message-passing-toolkit.html
Message Passing Interface - Functionality
1 MPI-1 and MPI-2 both enable implementations that overlap
communication and computation, but practice and theory differ. MPI also
specifies thread safe interfaces, which have cohesion and coupling strategies that help avoid hidden
state within the interface. It is relatively easy to write multithreaded
point-to-point MPI code, and some implementations support such code.
Multithreaded collective communication is best accomplished
with multiple copies of Communicators, as described below.
https://store.theartofservice.com/the-message-passing-toolkit.html
Message Passing Interface - Concepts
1 MPI provides a rich range of abilities. The following concepts help in
understanding and providing context for all of those abilities and help the
programmer to decide what functionality to use in their
application programs. Four of MPI's eight basic concepts are unique to
MPI-2.
https://store.theartofservice.com/the-message-passing-toolkit.html
Message Passing Interface - Communicator
1 Communicator objects connect groups of
processes in the MPI session
https://store.theartofservice.com/the-message-passing-toolkit.html
Message Passing Interface - Communicator
1 Communicators can be partitioned using several MPI commands. These commands include MPI_COMM_SPLIT,
where each process joins one of several colored sub-communicator by
declaring itself to have that color.
https://store.theartofservice.com/the-message-passing-toolkit.html
Message Passing Interface - Point-to-point basics
1 A number of important MPI functions involve communication between two specific
processes
https://store.theartofservice.com/the-message-passing-toolkit.html
Message Passing Interface - Point-to-point basics
1 MPI-1 specifies mechanisms for both blocking and non-blocking point-to-point communication mechanisms, as well as the so-called 'ready-send' mechanism whereby a send request
can be made only when the matching receive request has
already been made.
https://store.theartofservice.com/the-message-passing-toolkit.html
Message Passing Interface - Collective basics
1 Collective functions involve communication among all processes in a process group (which can mean the entire process pool or a program-
defined subset)
https://store.theartofservice.com/the-message-passing-toolkit.html
Message Passing Interface - Collective basics
1 Other operations perform more sophisticated tasks, such as
MPI_Alltoall which rearranges n items of data processor such that the nth node gets the nth item of data from
each.
https://store.theartofservice.com/the-message-passing-toolkit.html
Message Passing Interface - Derived datatypes
1 Many MPI functions require that you specify the type of data which is sent between processors. This is because these functions pass variables, not defined types. If the data type is a
standard one, such as int, char, double, etc., you can use predefined
MPI datatypes such as MPI_INT, MPI_CHAR, MPI_DOUBLE.
https://store.theartofservice.com/the-message-passing-toolkit.html
Message Passing Interface - Derived datatypes
1 However, you may instead wish to send data as one block as opposed to
100 ints. To do this define a "contiguous block" derived data type.
https://store.theartofservice.com/the-message-passing-toolkit.html
Message Passing Interface - Derived datatypes
1 Passing a class or a data structure cannot use a predefined data type. MPI_Type_create_struct creates an
MPI derived data type from MPI_predefined data types, as
follows:
https://store.theartofservice.com/the-message-passing-toolkit.html
Message Passing Interface - Derived datatypes
1 int MPI_Type_create_struct(int count, int blocklen[],
MPI_Aint disp[],
https://store.theartofservice.com/the-message-passing-toolkit.html
Message Passing Interface - Derived datatypes
1 where count is a number of blocks, also number of entries in blocklen[], disp[], and
type[]:
https://store.theartofservice.com/the-message-passing-toolkit.html
Message Passing Interface - Derived datatypes
1 blocklen[] — number of elements in each block (array
of integer)
https://store.theartofservice.com/the-message-passing-toolkit.html
Message Passing Interface - Derived datatypes
1 The disp[] array is needed because processors require the variables to
be aligned a specific way on the memory
https://store.theartofservice.com/the-message-passing-toolkit.html
Message Passing Interface - Derived datatypes
1 Given the following data structures:
https://store.theartofservice.com/the-message-passing-toolkit.html
Message Passing Interface - Derived datatypes
1 Here's the C code for building an MPI-derived
data type:
https://store.theartofservice.com/the-message-passing-toolkit.html
Message Passing Interface - Derived datatypes
1 //The first and last elements mark the beg
and end of data structure
https://store.theartofservice.com/the-message-passing-toolkit.html
Message Passing Interface - Derived datatypes
1 MPI_Datatype type={MPI_LB,
MPI_INT, MPI_SHORT, MPI_INT, MPI_INT,
MPI_UB};https://store.theartofservice.com/the-message-passing-toolkit.html
Message Passing Interface - Derived datatypes
1 //You need an array to establish the upper bound of
the data structure
https://store.theartofservice.com/the-message-passing-toolkit.html
Message Passing Interface - Derived datatypes
1 error=MPI_Type_create_s
truct(6, blocklen, disp, type, &newtype);
https://store.theartofservice.com/the-message-passing-toolkit.html
Message Passing Interface - One-sided communication
1 MPI-2 defines three one-sided communications operations, Put, Get,
and Accumulate, being a write to remote memory, a read from remote memory, and a reduction operation
on the same memory across a number of tasks. Also defined are
three different methods to synchronize this communication
(global, pairwise, and remote locks) as the specification does not
guarantee that these operations have taken place until a synchronization point.
https://store.theartofservice.com/the-message-passing-toolkit.html
Message Passing Interface - One-sided communication
1 These types of call can often be useful for algorithms in which
synchronization would be inconvenient (e.g. distributed matrix
multiplication), or where it is desirable for tasks to be able to balance their load while other
processors are operating on data.
https://store.theartofservice.com/the-message-passing-toolkit.html
Message Passing Interface - Dynamic process management
1 The key aspect is "the ability of an MPI process to participate in the
creation of new MPI processes or to establish communication with MPI processes that have been started
separately." The MPI-2 specification describes three main interfaces by
which MPI processes can dynamically establish communications,
MPI_Comm_spawn, MPI_Comm_accept/MPI_Comm_conne
ct and MPI_Comm_join
https://store.theartofservice.com/the-message-passing-toolkit.html
Message Passing Interface - I/O
1 The parallel I/O feature is sometimes called MPI-IO, and refers to a set of functions designed to abstract I/O
management on distributed systems to MPI, and allow files to be easily accessed in a patterned way using
the existing derived datatype functionality.
https://store.theartofservice.com/the-message-passing-toolkit.html
Message Passing Interface - I/O
1 The little research that has been done on this feature indicates the
difficulty for good performance. For example, some implementations of sparse matrix-vector multiplications
using the MPI I/O library are disastrously inefficient.
https://store.theartofservice.com/the-message-passing-toolkit.html
Message Passing Interface - 'Classical' cluster and supercomputer implementations
1 The MPI implementation language is not constrained to match the
language or languages it seeks to support at runtime. Most
implementations combine C, C++ and assembly language, and target C, C++, and Fortran programmers.
Bindings are available for many other languages, including Perl, Python, R,
Ruby, Java, CL.https://store.theartofservice.com/the-message-passing-toolkit.html
Message Passing Interface - 'Classical' cluster and supercomputer implementations
1 The initial implementation of the MPI 1.x standard was MPICH, from
Argonne National Laboratory (ANL) and Mississippi State University
https://store.theartofservice.com/the-message-passing-toolkit.html
Message Passing Interface - Python
1 MPI Python implementations include: pyMPI, mpi4py, pypar, MYMPI, and
the MPI submodule in ScientificPython. pyMPI is notable
because it is a variant python interpreter, while pypar, MYMPI, and ScientificPython's module are import modules. They make it the coder's
job to decide where the call to MPI_Init belongs. Recently the well
known Boost C++ Libraries acquired Boost:MPI which included the MPI
Python Bindings. This is of particular help for mixing C++ and Python.
https://store.theartofservice.com/the-message-passing-toolkit.html
Message Passing Interface - OCaml
1 The OCamlMPI Module implements a large subset of MPI functions and is in active use in scientific computing.
An eleven thousand line OCaml program was "MPI-ified" using the
module, with an additional 500 lines of code and slight restructuring and ran with excellent results on up to
170 nodes in a supercomputer.
https://store.theartofservice.com/the-message-passing-toolkit.html
Message Passing Interface - Java
1 Although Java does not have an official MPI binding, several groups
attempt to bridge the two, with different degrees of success and
compatibility. One of the first attempts was Bryan Carpenter's mpiJava, essentially a set of Java
Native Interface (JNI) wrappers to a local C MPI library, resulting in a
hybrid implementation with limited portability, which also has to be
compiled against the specific MPI library being used.
https://store.theartofservice.com/the-message-passing-toolkit.html
Message Passing Interface - Java
1 Beyond the API, Java MPI libraries can be either dependent on a local
MPI library, or implement the message passing functions in Java,
while some like P2P-MPI also provide peer-to-peer functionality and allow
mixed platform operation.
https://store.theartofservice.com/the-message-passing-toolkit.html
Message Passing Interface - Java
1 Some of the most challenging parts of Java/MPI arise from Java
characteristics such as the lack of explicit pointers and the linear memory address space for its
objects, which make transferring multidimensional arrays and complex
objects inefficient
https://store.theartofservice.com/the-message-passing-toolkit.html
Message Passing Interface - Java
1 Another Java message passing
system is MPJ Express
https://store.theartofservice.com/the-message-passing-toolkit.html
Message Passing Interface - Matlab
1 There are a few academic implementations of MPI using Matlab.
Matlab has their own parallel extension library implemented using
MPI and PVM
https://store.theartofservice.com/the-message-passing-toolkit.html
Message Passing Interface - R
1 MPI R implementations include: Rmpi and pbdMPI where Rmpi focuses on manager-workers parallelism while
pbdMPI focuses on SPMD parallelism. Both implementations fully support
Open MPI or MPICH2.
https://store.theartofservice.com/the-message-passing-toolkit.html
Message Passing Interface - Common Language Infrastructure
1 The two managed Common Language Infrastructure (CLI) .NET implementations are Pure Mpi.NET and MPI.NET, a research effort at
Indiana University licensed under a BSD-style license. It is compatible
with Mono, and can make full use of underlying low-latency MPI network
fabrics.
https://store.theartofservice.com/the-message-passing-toolkit.html
Message Passing Interface - Hardware implementations
1 MPI hardware research focuses on implementing MPI directly in
hardware, for example via processor-in-memory, building MPI operations into the microcircuitry of the RAM chips in each node. By implication, this approach is independent of the language, OS or CPU, but cannot be
readily updated or removed.
https://store.theartofservice.com/the-message-passing-toolkit.html
Message Passing Interface - Hardware implementations
1 Another approach has been to add hardware acceleration to one or
more parts of the operation, including hardware processing of MPI queues and using RDMA to directly transfer data between memory and
the network interface without CPU or OS kernel intervention.
https://store.theartofservice.com/the-message-passing-toolkit.html
Message Passing Interface - Example program
1 Here is a "Hello World" program in MPI written in C. In this example, we
send a "hello" message to each processor, manipulate it trivially,
return the results to the main process, and print the messages.
https://store.theartofservice.com/the-message-passing-toolkit.html
Message Passing Interface - Example program
1 /* At this point, all programs are running equivalently, the
rank
https://store.theartofservice.com/the-message-passing-toolkit.html
Message Passing Interface - Example program
1 distinguishes the roles of the programs in the SPMD
model, with
https://store.theartofservice.com/the-message-passing-toolkit.html
Message Passing Interface - Example program
1 rank 0 often used specially... */
https://store.theartofservice.com/the-message-passing-toolkit.html
Message Passing Interface - Example program
1 printf("%d: We have %d processors\n", myid,
numprocs);
https://store.theartofservice.com/the-message-passing-toolkit.html
Message Passing Interface - Example program
1 MPI_Send(buff, BUFSIZE, MPI_CHAR, i, TAG,
MPI_COMM_WORLD);
https://store.theartofservice.com/the-message-passing-toolkit.html
Message Passing Interface - Example program
1 MPI_Recv(buff, BUFSIZE, MPI_CHAR, i, TAG,
MPI_COMM_WORLD, &stat);
https://store.theartofservice.com/the-message-passing-toolkit.html
Message Passing Interface - Example program
1 strncat(buff, "reporting for duty\
n", BUFSIZE-1);
https://store.theartofservice.com/the-message-passing-toolkit.html
Message Passing Interface - Example program
1 The runtime environment for the MPI implementation used (often called
mpirun or mpiexec) spawns multiple copies of the program, with the total
number of copies determining the number of process ranks in
MPI_COMM_WORLD, which is an opaque descriptor for communication
between the set of processes
https://store.theartofservice.com/the-message-passing-toolkit.html
Message Passing Interface - Example program
1 MPI uses the notion of process rather than processor
https://store.theartofservice.com/the-message-passing-toolkit.html
Message Passing Interface - MPI-2 adoption
1 Adoption of MPI-1.2 has been universal, particularly in cluster
computing, but acceptance of MPI-2.1 has been more limited. Issues
include:
https://store.theartofservice.com/the-message-passing-toolkit.html
Message Passing Interface - MPI-2 adoption
1 MPI-2 implementations include I/O and dynamic process management,
and the size of the middleware is substantially larger. Most sites that
use batch scheduling systems cannot support dynamic process
management. MPI-2's parallel I/O is well accepted.
https://store.theartofservice.com/the-message-passing-toolkit.html
Message Passing Interface - MPI-2 adoption
1 Many MPI-1.2 programs were developed before MPI-2. Portability concerns initially slowed, although wider support has lessened this.
https://store.theartofservice.com/the-message-passing-toolkit.html
Message Passing Interface - MPI-2 adoption
1 Many MPI-1.2 applications use only a subset of that standard (16-25
functions) with no real need for MPI-2 functionality.
https://store.theartofservice.com/the-message-passing-toolkit.html
Message Passing Interface - Future
1 Some aspects of MPI's future appear solid; others less so. The MPI Forum reconvened in 2007, to clarify some
MPI-2 issues and explore developments for a possible MPI-3.
https://store.theartofservice.com/the-message-passing-toolkit.html
Message Passing Interface - Future
1 Like Fortran, MPI is ubiquitous in technical computing, and it is taught and used widely.
https://store.theartofservice.com/the-message-passing-toolkit.html
Message Passing Interface - Future
1 Architectures are changing, with greater internal concurrency (multi-core), better fine-grain concurrency
control (threading, affinity), and more levels of memory hierarchy
https://store.theartofservice.com/the-message-passing-toolkit.html
Message Passing Interface - Future
1 Improved fault tolerance within MPI would have clear benefits for the growing trend of grid computing.
https://store.theartofservice.com/the-message-passing-toolkit.html
Message Passing Interface - Notes
1 Jump up ^ High-performance and scalable MPI over InfiniBand with reduced memory
usage
https://store.theartofservice.com/the-message-passing-toolkit.html
Message Passing Interface - Notes
1 Jump up ^ Sparse matrix-vector
multiplications using the MPI I/O library
https://store.theartofservice.com/the-message-passing-toolkit.html
Message Passing Interface - Notes
1 Jump up ^ OCamlMPI Module
https://store.theartofservice.com/the-message-passing-toolkit.html
Message Passing Interface - Notes
1 Jump up ^ Yu, H. (2002). "Rmpi: Parallel Statistical Computing in R". R News.
https://store.theartofservice.com/the-message-passing-toolkit.html
Message Passing Interface - Notes
1 Jump up ^ Chen, W.-C., Ostrouchov, G., Schmidt, D., Patel, P., and Yu, H. (2012). "pbdMPI: Programming with
Big Data -- Interface to MPI".
https://store.theartofservice.com/the-message-passing-toolkit.html
Message Passing Interface - Notes
1 Jump up ^ Using OpenMPI, compiled with gcc -g -v
-I/usr/lib/openmpi/include/ -L/usr/lib/openmpi/include/
wiki_mpi_example.c -lmpi and run with mpirun -np 2 ./a.out.
https://store.theartofservice.com/the-message-passing-toolkit.html
Parallel programming model - Message passing
1 In a message passing model, parallel tasks exchange data through passing
messages to one another. These communications can be
asynchronous or synchronous. The Communicating Sequential Processes
(CSP) formalisation of message-passing employed communication
channels to 'connect' processes, and led to a number of important
languages such as Joyce, occam and Erlang.
https://store.theartofservice.com/the-message-passing-toolkit.html
Supercomputer - Software tools and message passing
1 The parallel architectures of supercomputers often dictate the use of special programming techniques
to exploit their speed. Software tools for distributed processing include
standard APIs such as MPI and PVM, VTL, and open source-based software
solutions such as Beowulf.
https://store.theartofservice.com/the-message-passing-toolkit.html
Supercomputer - Software tools and message passing
1 In the most common scenario, environments such as PVM and MPI for loosely connected clusters and
OpenMP for tightly coordinated shared memory machines are used.
Significant effort is required to optimize an algorithm for the
interconnect characteristics of the machine it will be run on; the aim is
to prevent any of the CPUs from wasting time waiting on data from
other nodes. GPGPUs have hundreds of processor cores and are
programmed using programming models such as CUDA.
https://store.theartofservice.com/the-message-passing-toolkit.html
Supercomputer - Software tools and message passing
1 Moreover, it is quite difficult to debug and test parallel programs. Special
techniques need to be used for testing and debugging such
applications.
https://store.theartofservice.com/the-message-passing-toolkit.html
High-performance computing - Software tools and message passing
1 The parallel architectures of supercomputers often dictate the use of special programming techniques
to exploit their speed. Software tools for distributed processing include
standard Application programming interface|APIs such as Message
Passing Interface|MPI and Parallel Virtual Machine|PVM, Virtual tape
library|VTL, and open source-based software solutions such as Beowulf
(computing)|Beowulf.
https://store.theartofservice.com/the-message-passing-toolkit.html
High-performance computing - Software tools and message passing
1 In the most common scenario, environments such as Parallel Virtual Machine|PVM and Message Passing Interface|MPI for loosely connected
clusters and OpenMP for tightly coordinated shared memory
machines are used
https://store.theartofservice.com/the-message-passing-toolkit.html
High-performance computing - Software tools and message passing
1 Moreover, it is quite difficult to debug and test parallel programs. Testing
high-performance computing applications|Special techniques need to be used for testing and debugging
such applications.
https://store.theartofservice.com/the-message-passing-toolkit.html
Message Passing Interface
1 'Message Passing Interface' ('MPI') is a standardized and portable
message-passing system designed by a group of researchers from
academia and industry to function on a wide variety of parallel computers
https://store.theartofservice.com/the-message-passing-toolkit.html
Message Passing Interface - History
1 Support for MPI meetings came in part from DARPA|ARPA and US
National Science Foundation under grant ASC-9310330, NSF Science and
Technology Center Cooperative agreement number CCR-8809615,
and the Commission of the European Community through Esprit Project
P6643. The University of Tennessee also made financial contributions to
the MPI Forum.https://store.theartofservice.com/the-message-passing-toolkit.html
Message Passing Interface - Overview
1 MPI is a language-independent communications protocol used to program parallel computers. Both
point-to-point and collective communication are supported. MPI is
a message-passing application programmer interface, together with protocol and semantic specifications for how its features must behave in
any implementation. MPI's goals are high performance, scalability, and
portability. MPI remains the dominant model used in high-performance computing today.
https://store.theartofservice.com/the-message-passing-toolkit.html
Message Passing Interface - Overview
1 [http://portal.acm.org/citation.cfm?id=1188565 High-performance and scalable MPI over InfiniBand with
reduced memory usage]
https://store.theartofservice.com/the-message-passing-toolkit.html
Message Passing Interface - Overview
1 MPI is not sanctioned by any major standards body; nevertheless, it has become a de facto standardization|standard for communication among
processes that model a parallel programming|parallel program
running on a distributed memory system
https://store.theartofservice.com/the-message-passing-toolkit.html
Message Passing Interface - Overview
1 The advantages of MPI over older message passing libraries are
portability (because MPI has been implemented for almost every
distributed memory architecture) and speed (because each implementation
is in principle optimized for the hardware on which it runs).
https://store.theartofservice.com/the-message-passing-toolkit.html
Message Passing Interface - Overview
1 MPI uses Language Independent Specifications (LIS) for calls and language bindings. The first MPI standard specified ANSI C and
Fortran-77 bindings together with the LIS. The draft was presented at
https://store.theartofservice.com/the-message-passing-toolkit.html
Message Passing Interface - Overview
1 Supercomputing 1994 (November 1994)[http://hpc.sagepub.com/conte
nt/8/3-4.toc] and finalized soon thereafter. About 128 functions constitute the MPI-1.3 standard
which was released as the final end of the MPI-1 series in
2008.[http://www.mpi-forum.org/docs/]
https://store.theartofservice.com/the-message-passing-toolkit.html
Message Passing Interface - Functionality
1 MPI library functions include, but are not limited to, point-to-point
rendezvous-type send/receive operations, choosing between a
Cartesian tree|Cartesian or Graph (data structure)|graph-like logical
process topology, exchanging data between process pairs (send/receive operations), combining partial results of computations (gather and reduce
operations), synchronizing nodes (barrier operation) as well as
obtaining network-related information such as the number of
processes in the computing session, current processor identity that a
process is mapped to, neighboring processes accessible in a logical
topology, and so on
https://store.theartofservice.com/the-message-passing-toolkit.html
Message Passing Interface - Functionality
1 MPI-1 and MPI-2 both enable implementations that overlap
communication and computation, but practice and theory differ
https://store.theartofservice.com/the-message-passing-toolkit.html
Message Passing Interface - Communicator
1 Communicator objects connect
groups of processes in the MPI session
https://store.theartofservice.com/the-message-passing-toolkit.html
Message Passing Interface - Point-to-point basics
1 MPI-1 specifies mechanisms for both blocking (computing)|blocking and
non-blocking point-to-point communication mechanisms, as well
as the so-called 'ready-send' mechanism whereby a send request
can be made only when the matching receive request has
already been made.
https://store.theartofservice.com/the-message-passing-toolkit.html
Message Passing Interface - Collective basics
1 Collective operation|Collective functions involve communication among all processes in a process group (which can mean the entire process pool or a program-defined
subset)
https://store.theartofservice.com/the-message-passing-toolkit.html
Message Passing Interface - Derived datatypes
1 * blocklen[] — number of elements in each block (array
of integer)
https://store.theartofservice.com/the-message-passing-toolkit.html
Message Passing Interface - Derived datatypes
1 The disp[] array is needed because processors require the variables to
be aligned a specific way on the memory
https://store.theartofservice.com/the-message-passing-toolkit.html
Message Passing Interface - if(myid
1 Each process has its own rank, the total number of processes in the
world, and the ability to communicate between them either with point-to-point (send/receive) communication, or by collective
communication among the group
https://store.theartofservice.com/the-message-passing-toolkit.html
Message Passing Interface - if(myid
1 MPI uses the notion of process rather than processor
https://store.theartofservice.com/the-message-passing-toolkit.html
Message Passing Interface - MPI-2 adoption
1 # MPI-2 implementations include I/O and dynamic process management,
and the size of the middleware is substantially larger. Most sites that
use batch scheduling systems cannot support dynamic process
management. MPI-2's parallel I/O is well accepted.
https://store.theartofservice.com/the-message-passing-toolkit.html
Message Passing Interface - MPI-2 adoption
1 # Many MPI-1.2 programs were developed before MPI-2. Portability concerns initially slowed, although wider support has lessened this.
https://store.theartofservice.com/the-message-passing-toolkit.html
Message Passing Interface - MPI-2 adoption
1 # Many MPI-1.2 applications use only a subset of that standard (16-25
functions) with no real need for MPI-2 functionality.
https://store.theartofservice.com/the-message-passing-toolkit.html
Message Passing Interface - Future
1 Some aspects of MPI's future appear solid; others less so. The MPI Forum reconvened in 2007, to clarify some
MPI-2 issues and explore developments for a possible MPI-3.
https://store.theartofservice.com/the-message-passing-toolkit.html
Message Passing Interface - Future
1 Architectures are changing, with greater internal concurrency (multi-core), better fine-grain concurrency
control (threading, affinity), and more levels of memory hierarchy
https://store.theartofservice.com/the-message-passing-toolkit.html
Computer clusters - Message passing and communication
1 Two widely used approaches for communication between cluster
nodes are MPI, the Message Passing Interface and PVM, the Parallel
Virtual Machine.Distributed services with OpenAFS: for enterprise and
education by Franco Milicchio, Wolfgang Alexander Gehrke 2007,
ISBN pages 339-341 [http://books.google.it/books?
id=bKf4NBaIJI8Cpg=PA339dq=%22message+passing
%22+computer+cluster+MPI+PVMhl=ensa=Xei=-
dD7ToZCj_bhBOOxvI0Iredir_esc=y#v=onepageq=%22message
%20passing%22%20computer%20cluster%20MPI%20PVMf=false]
https://store.theartofservice.com/the-message-passing-toolkit.html
Computer clusters - Message passing and communication
1 MPI emerged in the early 1990s out of discussions among 40 organizations
https://store.theartofservice.com/the-message-passing-toolkit.html
Real-time operating system - Message passing
1 The other approach to resource sharing is for tasks to send messages
in an organized message passing scheme
https://store.theartofservice.com/the-message-passing-toolkit.html
Goto - Message passing
1 One of the main alternatives is message passing, which is of
particular importance in concurrent computing, interprocess
communication, and object oriented programming
https://store.theartofservice.com/the-message-passing-toolkit.html
SIMPL - Advantages of Synchronized Message Passing
1 * Inherent thread synchronization coordinates the execution of communicating programs
https://store.theartofservice.com/the-message-passing-toolkit.html
SIMPL - Advantages of Synchronized Message Passing
1 * No data buffering is required
https://store.theartofservice.com/the-message-passing-toolkit.html
Multi-processor - Message passing
1 processors communicate via message passing.
https://store.theartofservice.com/the-message-passing-toolkit.html
Multi-processor - Message passing
1 focus attention on costly non-local
operations.
https://store.theartofservice.com/the-message-passing-toolkit.html
Event loop - Message passing
1 The event loop is a specific implementation technique of systems that use message
passing.
https://store.theartofservice.com/the-message-passing-toolkit.html
Message (computer science) - Synchronous versus asynchronous message passing
1 One of the most important distinctions among message passing
systems is whether they use synchronous or asynchronous
message passing. Synchronous message passing occurs between
objects that are running at the same time. With asynchronous message
passing it is possible for the receiving object to be busy or not running
when the requesting object sends the message.
https://store.theartofservice.com/the-message-passing-toolkit.html
Message (computer science) - Synchronous versus asynchronous message passing
1 Synchronous message passing is what typical object-oriented
programming languages such as Java and Smalltalk use. Asynchronous
message passing requires additional capabilities for storing and
retransmitting data for systems that may not run concurrently.
https://store.theartofservice.com/the-message-passing-toolkit.html
Message (computer science) - Synchronous versus asynchronous message passing
1 For example, if synchronous message passing would be used exclusively, large, distributed systems generally would not perform well enough to be
usable
https://store.theartofservice.com/the-message-passing-toolkit.html
Message (computer science) - Synchronous versus asynchronous message passing
1 Imagine a busy business office having 100 desktop computers that
send emails to each other using synchronous message passing exclusively. Because the office
system does not use asynchronous message passing, one worker turning
off their computer can cause the other 99 computers to freeze until
the worker turns their computer back on to process a single email.
https://store.theartofservice.com/the-message-passing-toolkit.html
Message (computer science) - Synchronous versus asynchronous message passing
1 Asynchronous message passing is generally implemented so that all the
complexities that naturally occur when trying to synchronize systems
and data are handled by an intermediary level of software.
Commercial vendors who develop software products to support these
intermediate levels usually call their software middleware. One of the
most common types of middleware to support asynchronous messaging
is called Message-oriented middleware|Message Oriented
Middleware (MOM)
https://store.theartofservice.com/the-message-passing-toolkit.html
Message (computer science) - Synchronous versus asynchronous message passing
1 Asynchronous message passing simply sends the message to the message
bus
https://store.theartofservice.com/the-message-passing-toolkit.html
Message (computer science) - Message passing versus calling
1 Distributed or asynchronous message passing has some overhead
associated with it compared to the simpler way of simply calling a
procedure. In a traditional Calling convention|procedure call,
arguments are passed to the receiver typically by one or more general
purpose registers or in a Parameter (computer science)|parameter list
containing the addresses of each of the arguments. This form of
communication differs from message passing in at least three crucial
areas:
https://store.theartofservice.com/the-message-passing-toolkit.html
Message (computer science) - Message passing versus calling
1 In message passing, each of the arguments has to copy the existing argument into a portion of the new message. This applies regardless of
the size of the argument and in some cases the arguments can be as large
as a document which can be megabytes worth of data. The
argument has to be copied in its entirety and transmitted to the
receiving object.https://store.theartofservice.com/the-message-passing-toolkit.html
Message (computer science) - Message passing versus calling
1 By contrast, for a standard procedure call, only an address (a few bits)
needs to be passed for each argument and may even be passed
in a general purpose register requiring zero additional storage and
zero transfer time.
https://store.theartofservice.com/the-message-passing-toolkit.html
Message (computer science) - Message passing versus calling
1 Web web browsing|browsers and web servers are examples of processes
that communicate by message passing
https://store.theartofservice.com/the-message-passing-toolkit.html
Message (computer science) - Message passing versus calling
1 A subroutine call or method (computer programming)|method invocation will not exit until the
invoked computation has terminated. Asynchronous message passing, by contrast, can result in a response
arriving a significant time after the request message was sent.
https://store.theartofservice.com/the-message-passing-toolkit.html
Message passing (disambiguation)
1 * Message passing, a mechanism for
interprocess communication
https://store.theartofservice.com/the-message-passing-toolkit.html
Message passing (disambiguation)
1 * Message passing algorithms for probabilistic inference, such as Belief propagation or variational message
passing.
https://store.theartofservice.com/the-message-passing-toolkit.html
Message passing in computer clusters
1 Beowulf Cluster Computing With Windows by Thomas Lawrence
Sterling 2001 ISBN 0262692759 MIT Press pages 7–9 Message passing in
computer clusters built with commodity Server (computing)|
servers and Network switch|switches is used by virtually every internet
service.Computer Organization and Design by David Patterson (scientist)|
David Ahttps://store.theartofservice.com/the-message-passing-toolkit.html
Message passing in computer clusters
1 As the number of nodes in a cluster increases, the rapid growth in the complexity of the communication
subsystem makes message passing delays over the Switched fabric|
interconnect a serious performance issue in the execution of parallel programs.Recent Advances in the
Message Passing Interface by Yiannis Cotronis, Anthony Danalis, Dimitris
Nikolopoulos and Jack Dongarra 2011 ISBN 3642244483 pages 160–162
https://store.theartofservice.com/the-message-passing-toolkit.html
Message passing in computer clusters
1 Before a large computer cluster is assembled, a trace-based simulator can use a small number of nodes to
help predict the performance of message passing on larger
configurations
https://store.theartofservice.com/the-message-passing-toolkit.html
Message passing in computer clusters - Approaches to message passing
1 Historically, the two typical approaches to communication
between cluster nodes have been PVM, the Parallel Virtual Machine and
MPI, the Message Passing Interface.Distributed services with
OpenAFS: for enterprise and education by Franco Milicchio,
Wolfgang Alexander Gehrke 2007, ISBN pages 339-341 However, MPI has now emerged as the de facto standard for message passing on
computer clusters.Recent Advances in Parallel Virtual Machine and
Message Passing Interface by Matti Ropo, Jan Westerholm and Jack
Dongarra 2009 ISBN 3642037690 page 231
https://store.theartofservice.com/the-message-passing-toolkit.html
Message passing in computer clusters - Approaches to message passing
1 PVM predates MPI and was developed at the Oak Ridge National Laboratory around 1989. It provides
a set of software libraries that allow a computing node to act as a parallel virtual machine. It provides run-time environment for message-passing,
task and resource management, and fault notification and must be directly installed on every cluster node. PVM
can be used by user programs written in C language|C, C++, or
Fortran, etc.
https://store.theartofservice.com/the-message-passing-toolkit.html
Message passing in computer clusters - Approaches to message passing
1 Unlike PVM, which has a concrete implementation, MPI is a
specification rather than a specific set of libraries
https://store.theartofservice.com/the-message-passing-toolkit.html
Message passing in computer clusters - Testing, evaluation and optimization
1 Tiahnhe-I uses over two thousand FeiTeng-1000 processors to enhance
the operation of its proprietary message passing system, while
computations are performed by Xeon and Nvidia Tesla processors.The TianHe-1A Supercomputer: Its
Hardware and Software by Xue-Jun Yang, Xiang-Ke Liao, et al in the Journal of Computer Science and
Technology, Volume 26, Number 3, May 2011, pages
344–351[http://jcst.ict.ac.cn:8080/jcst/EN/article/downloadArticleFile.do?
attachType=PDFid=9388]U.S
https://store.theartofservice.com/the-message-passing-toolkit.html
Message passing in computer clusters - Testing, evaluation and optimization
1 One approach to reducing communication overhead is the use of local neighborhoods (also called
Locale (computer hardware)|locales) for specific tasks
https://store.theartofservice.com/the-message-passing-toolkit.html
Message passing in computer clusters - Testing, evaluation and optimization
1 Given that MPI has now emerged as the de facto standard on computer
clusters, the increase in the number of cluster nodes has resulted in
continued research to improve the efficiency and scalability of MPI
libraries. These efforts have included research to reduce the memory
footprint of MPI libraries.
https://store.theartofservice.com/the-message-passing-toolkit.html
Message passing in computer clusters - Testing, evaluation and optimization
1 This is achieved by registering callbacks with Peruse, and then
invoking them as triggers as message events take place.Recent
Advances in Parallel Virtual Machine and Message Passing Interface by Bernd Mohr, Jesper Larsson Träff,
Joachim Worringen and Jack Dongarra 2006 ISBN 354039110X
page 347 Peruse can work with the PARAVER visualization system
https://store.theartofservice.com/the-message-passing-toolkit.html
Message passing in computer clusters - Testing, evaluation and optimization
1 PARAVER: A Tool to Visualize and Analyze Parallel Code by Vincent
Pillet et al, Proceedings of the conference on Transputer and Occam
Developments, 1995, pages 17–31 PARAVER may use trace formats from
other systems, or perform its own tracing
https://store.theartofservice.com/the-message-passing-toolkit.html
Message passing in computer clusters - Performance analysis
1 Systems such as BIGSIM provide these facilities by allowing the
simulation of performance on various network topology|node topologies, message passing and scheduling strategies.Petascale Computing:
Algorithms and Applications by David A
https://store.theartofservice.com/the-message-passing-toolkit.html
Message passing in computer clusters - Analytical approaches
1 A well knowm model is Hockney's model which simply relies on point to point communication, using T = L + (M / R) where M is the message size, L is the startup latency and R is the
asymptotic bandwidth in MB/s.Modeling Message Passing
Overhead by C.Y Chou et al
https://store.theartofservice.com/the-message-passing-toolkit.html
Message passing in computer clusters - Analytical approaches
1 Xu and Hwang generalized Hockney's model to include the number of processors, so that both the latency and the asymptotic bandwidth are functions of the number of processors.High-
Performance Computing and Networking edited by Peter Sloot, Marian Bubak and Bob Hertzberge 1998 ISBN 3540644431 page 935 Gunawan and Cai then generalized this further by introducing
Cache (computing)|cache size, and separated the messages based on their sizes, obtaining two
separate models, one for messages below cache size, and one for those above.
https://store.theartofservice.com/the-message-passing-toolkit.html
Message passing in computer clusters - Performance simulation
1 The communication overhead for Message Passing Interface|MPI message passing can thus be
simulated and better understood in the context of large-scale parallel job
execution.High Performance Computational Science and
Engineering edited by Michael K
https://store.theartofservice.com/the-message-passing-toolkit.html
Message passing in computer clusters - Performance simulation
1 Other simulation tools include MPI-sim and BIGSIM.Advances in
Computer Science, Environment, Ecoinformatics, and Education edited by Song Lin and Xiong Huang 2011
ISBN 3642233236 page 16 MPI-Sim is an execution-driven simulator that
requires C or C++ programs to operate. ClusterSim, on the other hand uses a hybrid higher-level
modeling system independent of the programming language used for
program execution.
https://store.theartofservice.com/the-message-passing-toolkit.html
Message passing in computer clusters - Performance simulation
1 Unlike MPI-Sim, BIGSIM is a trace-driven system that simulates based on the logs of executions saved in
files by a separate emulator program.Languages and Compilers
for Parallel Computing edited by Keith Cooper, John Mellor-Crummey
and Vivek Sarkar 2011 ISBN 3642195946 pages 202–203 BIGSIM
includes an emulator, and a simulator
https://store.theartofservice.com/the-message-passing-toolkit.html
Transient (computer programming) - Message passing
1 At the level of message passing, transient communication means the way by which the messages are not
saved into a buffer to wait for its deliver at the message receiver. The
messages will be delivered only if both the systems (sender and
receiver) are running. If the receiver is not running at the send time, the message will be discarded, because
it has not been stored into intermediate buffers.
https://store.theartofservice.com/the-message-passing-toolkit.html
For More Information, Visit:
• https://store.theartofservice.com/the-message-passing-toolkit.html
The Art of Servicehttps://store.theartofservice.com
Recommended