Goals of this lecture - SPCL · Goals of this lecture Motivate you! ... Source: Can we do this today? 5 Source: Blue Waters, ~13 PF (2012)

Design of Parallel and High-Performance Computing Fall 2014 Lecture: Introduction

Instructor: Torsten Hoefler & Markus Püschel

TA: Timo Schneider

Goals of this lecture

Motivate you!

What is parallel computing?

And why do we need it?

What is high-performance computing?

What’s a Supercomputer and why do we care?

Basic overview of

Programming models

Some examples

Architectures

Some case-studies

Provide context for coming lectures

2

Let us assume …

… you were to build a machine like this …

… we know how each part works

There are just many of them!

Question: How many calculations per second are needed to emulate a brain? 3

Source: wikipedia

4

Source: www.singularity.com Can we do this today?

5

Source: www.singularity.com Blue Waters, ~13 PF (2012)

Tianhe-2, ~55 PF (2013)

1 Exaflop! ~2022?

Human Brain – No Problem!

… not so fast, we need to understand how to program those machines …

6

Human Brain – No Problem!

7

Scooped!

Source: extremetech.com

Under the Kei Computer

8

Other problem areas: Scientific Computing

Most natural sciences are simulation driven or are moving towards simulation Theoretical physics (solving the Schrödinger equation, QCD) Biology (Gene sequencing) Chemistry (Material science) Astronomy (Colliding black holes) Medicine (Protein folding for drug discovery) Meteorology (Storm/Tornado prediction) Geology (Oil reservoir management, oil exploration) and many more … (even Pringles uses HPC)

9

Other problem areas: Commercial Computing

Databases, data mining, search Amazon, Facebook, Google

Transaction processing Visa, Mastercard

Decision support Stock markets, Wall Street, Military applications

Parallelism in high-end systems and back-ends Often throughput-oriented Used equipment varies from COTS (Google) to high-end redundant

mainframes (banks)

10

Other problem areas: Industrial Computing

Aeronautics (airflow, engine, structural mechanics, electromagnetism)

Automotive (crash, combustion, airflow)

Computer-aided design (CAD)

Pharmaceuticals (molecular modeling, protein folding, drug design)

Petroleum (Reservoir analysis)

Visualization (all of the above, movies, 3d)

11

What can faster computers do for us?

Solving bigger problems than we could solve before!

E.g., Gene sequencing and search, simulation of whole cells, mathematics of the brain, …

The size of the problem grows with the machine power

Weak Scaling

Solve today’s problems faster!

E.g., large (combinatorial) searches, mechanical simulations (aircrafts, cars, weapons, …)

The machine power grows with constant problem size

Strong Scaling

12

High-Performance Computing (HPC)

a.k.a. “Supercomputing”

Question: define “Supercomputer”!

13

High-Performance Computing (HPC)

a.k.a. “Supercomputing”

Question: define “Supercomputer”!

“A supercomputer is a computer at the frontline of contemporary processing capacity--particularly speed of calculation.” (Wikipedia)

Usually quite expensive ($s and kWh) and big (space)

HPC is a quickly growing niche market

Not all “supercomputers”, wide base

Important enough for vendors to specialize

Very important in research settings (up to 40% of university spending)

“Goodyear Puts the Rubber to the Road with High Performance Computing”

“High Performance Computing Helps Create New Treatment For Stroke Victims”

“Procter & Gamble: Supercomputers and the Secret Life of Coffee”

“Motorola: Driving the Cellular Revolution With the Help of High Performance Computing”

“Microsoft: Delivering High Performance Computing to the Masses”

14

The Top500 List

A benchmark, solve Ax=b

As fast as possible! as big as possible

Reflects some applications, not all, not even many

Very good historic data!

Speed comparison for computing centers, states, countries, nations, continents

Politicized (sometimes good, sometimes bad)

Yet, fun to watch

15

The Top500 List (June 2014)

16

Piz Daint @ CSCS

18

Blue Waters in 2009

This is why you need to understand performance expectations well!

Imagine you’re designing a $500 M supercomputer, and all you have is:

Blue Waters in 2012

History and Trends

21 Source: Jack Dongarra

Single GPU/MIC Card

High-Performance Computing grows quickly

Computers are used to automate many tasks

Still growing exponentially

New uses discovered continuously

22

Source: The Economist

IDC, 2007: “The overall HPC server market grew by 15.5 percent in 2007 to reach $11.6 billion […] while the same kinds of boxes that go into HPC machinery but are used for general purpose computing, rose by only 3.6 percent to $54.4”

IDC, 2009: “expects the HPC technical server market to grow at a healthy 7% to 8% yearly rate to reach revenues of $13.4 billion by 2015.” “The non-HPC portion of the server market was actually down 20.5 per cent, to $34.6bn”

How to increase the compute power?

23

4004 8008

8080

8085

8086

286 386 486

Pentium® Processors

1

10

100

1000

10000

1970 1980 1990 2000 2010

Po

we

r D

en

sity

(W

/cm

2)

Source: Intel

Hot Plate

Nuclear Reactor

Rocket Nozzle

Sun’s Surface

Clock Speed:

How to increase the compute power?

24

4004 8008

8080

8085

8086

286 386 486

Pentium® Processors

1

10

100

1000

10000

1970 1980 1990 2000 2010

Po

we

r D

en

sity

(W

/cm

2)

Source: Intel

Hot Plate

Nuclear Reactor

Rocket Nozzle

Sun’s Surface

Clock Speed: Not an option anymore!

25

Source: Wikipedia

A more complete view

26

So how to invest the transistors?

Architectural innovations Branch prediction, Tomasulo logic/rename register, speculative execution,

…

Help only so much

What else? Simplification is beneficial, less transistors per CPU, more CPUs, e.g., Cell

B.E., GPUs, MIC

We call this “cores” these days

Also, more intelligent devices or higher bandwidths (e.g., DMA controller, intelligent NICs)

27

Source: IBM Source: NVIDIA Source: Intel

Towards the age of massive parallelism

Everything goes parallel

Desktop computers get more cores

2,4,8, soon dozens, hundreds?

Supercomputers get more PEs (cores, nodes)

> 3 million today

> 50 million on the horizon

1 billion in a couple of years (after 2020)

Parallel Computing is inevitable!

28

Parallel vs. Concurrent computing Concurrent activities may be executed in parallel Example: A1 starts at T1, ends at T2; A2 starts at T3, ends at T4 Intervals (T1,T2) and (T3,T4) may overlap! Parallel activities: A1 is executed while A2 is running Usually requires separate resources!


Motivate you!





Basic overview of

Programming models

Some examples

Architectures

Some case-studies


29

Granularity and Resources

30

Activities

Micro-code instruction

Machine-code instruction (complex or simple)

Sequence of machine-code instructions:

Blocks

Loops

Loop nests

Functions

Function sequences

Parallel Resource

Instruction-level parallelism

Pipelining

VLIW

Superscalar

SIMD operations

Vector operations

Instruction sequences

Multiprocessors

Multicores

Multithreading

Resources and Programming

31

Parallel Resource

Instruction-level parallelism

Pipelining

VLIW

Superscalar

SIMD operations

Vector operations

Instruction sequences

Multiprocessors

Multicores

Multithreading

Programming

Compiler

(inline assembly)

Hardware scheduling

Compiler (inline assembly)

Libraries

Compilers (very limited)

Expert programmers

Parallel languages

Parallel libraries

Hints

Historic Architecture Examples

Systolic Array

Data-stream driven (data counters)

Multiple streams for parallelism

Specialized for applications (reconfigurable)

Dataflow Architectures

No program counter, execute instructions when all input arguments are available

Fine-grained, high overheads

Example: compute f = (a+b) * (c+d)

32

Source: ni.com

Source: isi.edu

Von Neumann Architecture

Program counter Inherently serial! Retrospectively define parallelism in instructions and data

33

SISD Standard Serial Computer

(nearly extinct)

SIMD Vector Machines or Extensions

(very common)

MISD Redundant Execution

(fault tolerance)

MIMD Multicore

(ubiquituous)

Parallel Architectures 101

… and mixtures of those

34

Today’s laptops Today’s servers

Yesterday’s clusters Today’s clusters

Programming Models

Shared Memory Programming (SM/UMA)

Shared address space

Implicit communication

Hardware for cache-coherent remote memory access

Cache-coherent Non Uniform Memory Access (cc NUMA)

(Partitioned) Global Address Space (PGAS)

Remote Memory Access

Remote vs. local memory (cf. ncc-NUMA)

Distributed Memory Programming (DM)

Explicit communication (typically messages)

Message Passing

35

Shared Memory Machines

Two historical architectures:

“Mainframe” – all-to-all connection between memory, I/O and PEs

Often used if PE is the most expensive part

Bandwidth scales with P

PE Cost scales with P, Question: what about network cost?

36

Source: IBM

Shared Memory Machines

Two historical architectures:

“Mainframe” – all-to-all connection between memory, I/O and PEs

Often used if PE is the most expensive part

Bandwidth scales with P

PE Cost scales with P, Question: what about network cost?

Answer: Cost can be cut with multistage connections (butterfly)

“Minicomputer” – bus-based connection All traditional SMP systems

High latency, low bandwidth (cache is important)

Tricky to achieve highest performance (contention)

Low cost, extensible

37

Source: IBM

Shared Memory Machine Abstractions

Any PE can access all memory

Any I/O can access all memory (maybe limited)

OS (resource management) can run on any PE

Can run multiple threads in shared memory

Used since 40+ years

Communication through shared memory

Load/store commands to memory controller

Communication is implicit

Requires coordination

Coordination through shared memory

Complex topic

Memory models

38

Shared Memory Machine Programming

Threads or processes

Communication through memory

Synchronization through memory or OS objects

Lock/mutex (protect critical region)

Semaphore (generalization of mutex (binary sem.))

Barrier (synchronize a group of activities)

Atomic Operations (CAS, Fetch-and-add)

Transactional Memory (execute regions atomically)

Practical Models:

Posix threads

MPI-3

OpenMP

Others: Java Threads, Qthreads, …

39

An SMM Example: Compute Pi

40

Using Gregory-Leibnitz Series:

Iterations of sum can be computed in parallel

Needs to sum all contributions at the end

Source: mathworld.wolfram.com

Pthreads Compute Pi Example

41

int main( int argc, char *argv[] )

{

// definitions …

thread_arr = (pthread_t*)malloc(nthreads * sizeof(pthread_t));

resultarr= (double*)malloc(nthreads * sizeof(double));

for (i=0; i<nthreads; ++i) {

int ret = pthread_create( &thread_arr[i], NULL,

compute_pi, (void*) i);

}

for (i=0; i<nthreads; ++i) {

pthread_join( thread_arr[i], NULL);

}

pi = 0;

for (i=0; i<nthreads; ++i) pi += resultarr[i];

printf ("pi is approximately %.16f, Error is %.16f\n",

pi, fabs(pi - PI25DT));

}

int n=10000;

double *resultarr;

int nthreads;

void *compute_pi(void *data) {

int i, j;

int myid = (int)(long)data;

double mypi, h, x, sum;

for (j=0; j<n; ++j) {

h = 1.0 / (double) n;

sum = 0.0;

for (i = myid + 1; i <= n; i += nthreads) {

x = h * ((double)i - 0.5);

sum += (4.0 / (1.0 + x*x));

}

mypi = h * sum;

}

resultarr[myid] = mypi;

}

Additional comments on SMM

OpenMP would allow to implement this example much simpler (but has other issues)

Transparent shared memory has some issues in practice:

False sharing (e.g., resultarr[])

Race conditions (complex mutual exclusion protocols)

Little tool support (debuggers need some work)

Achieving performance is harder than it seems!

42

Distributed Memory Machine Programming

Explicit communication between PEs

Message passing or channels

Only local memory access, no direct access to remote memory

No shared resources (well, the network)

Programming model: Message Passing (MPI, PVM)

Communication through messages or group operations (broadcast, reduce, etc.)

Synchronization through messages (sometimes unwanted side effect) or group operations (barrier)

Typically supports message matching and communication contexts

43

Send specifies buffer to be transmitted

Recv specifies buffer to receive into

Implies copy operation between named PEs

Optional tag matching

Pair-wise synchronization (cf. happens before)

DMM Example: Message Passing

44

Pr ocess P Pr ocess Q

Addr ess Y

Addr ess X

Send X, Q, t

Receive Y , P , t Match

Local pr ocess addr ess space

Local pr ocess addr ess space

Source: John Mellor-Crummey

DMM MPI Compute Pi Example

45

int main( int argc, char *argv[] ) {

// definitions

MPI_Init(&argc,&argv);

MPI_Comm_size(MPI_COMM_WORLD, &numprocs);

MPI_Comm_rank(MPI_COMM_WORLD, &myid);

double t = -MPI_Wtime();

for (j=0; j<n; ++j) {

h = 1.0 / (double) n;

sum = 0.0;

for (i = myid + 1; i <= n; i += numprocs) { x = h * ((double)i - 0.5); sum += (4.0 / (1.0 + x*x)); }

mypi = h * sum;

MPI_Reduce(&mypi, &pi, 1, MPI_DOUBLE, MPI_SUM, 0, MPI_COMM_WORLD);

}

t+=MPI_Wtime();

if (!myid) {

printf("pi is approximately %.16f, Error is %.16f\n", pi, fabs(pi - PI25DT));

printf("time: %f\n", t);

}

MPI_Finalize();

}

DMM Example: PGAS

Partitioned Global Address Space

Shared memory emulation for DMM

Usually non-coherent

“Distributed Shared Memory”

Usually coherent

Simplifies shared access to distributed data

Has similar problems as SMM programming

Sometimes lacks performance transparency

Local vs. remote accesses

Examples:

UPC, CAF, Titanium, X10, …

46

How to Tame the Beast?

How to program large machines?

No single approach, PMs are not converging yet

MPI, PGAS, OpenMP, Hybrid (MPI+OpenMP, MPI+MPI, MPI+PGAS?), …

Architectures converge

General purpose nodes connected by general purpose or specialized networks

Small scale often uses commodity networks

Specialized networks become necessary at scale

Even worse: accelerators (not covered in this class, yet)

47

Practical SMM Programming: Pthreads

48

Kernel

User

CPU 0 CPU 1

Kernel

User

CPU 0 CPU 1

User-level Threads Kernel-level Threads

Covered in example, small set of functions for thread creation and management

Practical SMM Programming:

Fork-join model

Types of constructs:

Source: OpenMP.org

Source: Blaise Barney, LLNL

+ Tasks

OpenMP General Code Structure

50

#include <omp.h>

main () {

int var1, var2, var3;

// Serial code

// Beginning of parallel section. Fork a team of threads. Specify variable scoping

#pragma omp parallel private(var1, var2) shared(var3)

{

// Parallel section executed by all threads

// Other OpenMP directives

// Run-time Library calls

// All threads join master thread and disband

}

// Resume serial code

}


Practical PGAS Programming: UPC

PGAS extension to the C99 language

Many helper library functions

Collective and remote allocation

Collective operations

Complex consistency model

51

Practical DMM Programming: MPI-1

52 Collection of 1D address spaces

Helper Functions

many more (>600 total)


Complete Six Function MPI-1 Example

53

#include <mpi.h>

int main(int argc, char **argv) {

int myrank, sbuf=23, rbuf=32;

MPI_Init(&argc, &argv);

/* Find out my identity in the default communicator */

MPI_Comm_rank(MPI_COMM_WORLD, &myrank);

if (myrank == 0) {

MPI_Send(&sbuf, /* message buffer */

1, /* one data item */

MPI_INT, /* data item is an integer */

rank, /* destination process rank */

99, /* user chosen message tag */

MPI_COMM_WORLD); /* default communicator */

} else {

MPI_Recv(&rbuf, MPI_DOUBLE, 0, 99, MPI_COMM_WORLD, &status);

printf(“received: %i\n”, rbuf);

}

MPI_Finalize();

}

MPI-2/3: Greatly enhanced functionality

Support for shared memory in SMM domains

Support for Remote Memory Access Programming

Direct use of RDMA

Essentially PGAS

Enhanced support for message passing communication

Scalable topologies

More nonblocking features

… many more

54

MPI: de-facto large-scale prog. standard

55 To appear at SC14 (11/17/2014)

Basic MPI Advanced MPI, including MPI-3

Accelerator example: CUDA

56

Hierarchy of Threads

Complex Memory Model

Simple Architecture

Source: NVIDIA

Accelerator example: CUDA

57

#define N 10

int main( void ) {

int a[N], b[N], c[N];

int *dev_a, *dev_b, *dev_c;

// allocate the memory on the GPU

cudaMalloc( (void**)&dev_a, N * sizeof(int) );

cudaMalloc( (void**)&dev_b, N * sizeof(int) );

cudaMalloc( (void**)&dev_c, N * sizeof(int) );

// fill the arrays 'a' and 'b' on the CPU

for (int i=0; i<N; i++) { a[i] = -i; b[i] = i * i; }

// copy the arrays 'a' and 'b' to the GPU

cudaMemcpy( dev_a, a, N * sizeof(int), cudaMemcpyHostToDevice );

cudaMemcpy( dev_b, b, N * sizeof(int), cudaMemcpyHostToDevice );

add<<<N,1>>>( dev_a, dev_b, dev_c );

// copy the array 'c' back from the GPU to the CPU

cudaMemcpy( c, dev_c, N * sizeof(int), cudaMemcpyDeviceToHost );

// free the memory allocated on the GPU

cudaFree( dev_a ); cudaFree( dev_b ); cudaFree( dev_c );

}

__global__ void add( int *a, int *b, int *c ) {

int tid = blockIdx.x;

// handle the data at this index

if (tid < N)

c[tid] = a[tid] + b[tid];

}

The Kernel

Host Code

OpenACC / OpenMP 4.0

Aims to simplify GPU programming

Compiler support

Annotations!

58

#define N 10

int main( void ) {

int a[N], b[N], c[N];

#pragma acc kernels

for (int i = 0; i < N; ++i)

c[i] = a[i] + b[i];

}

More programming models/frameworks

Not covered:

SMM: Intel Cilk / Cilk Plus, Intel TBB, …

Directives: OpenHMPP, PVM, …

PGAS: Coarray Fortran (Fortran 2008), …

HPCS: IBM X10, Fortress, Chapel, …

Accelerator: OpenCL, C++AMP, …

This class will not describe any model in more detail!

There are too many and they will change quickly (only MPI made it >15 yrs)

No consensus, but fundamental questions remain:

Data movement

Synchronization

Memory Models

Algorithmics

Foundations

59


Motivate you!





Basic overview of

Programming models

Some examples

Architectures

Some case-studies


60

large cache-

coherent multicore

machines

communicating

through coherent

memory access

and remote direct

memory access

Architecture Developments

’00-’05 <1999 ’06-’12 ’13-’20 >2020

distributed

memory

machines

communicating

through

messages

large cache-

coherent multicore

machines

communicating

through coherent

memory access

and messages

coherent and non-

coherent

manycore

accelerators and

multicores

communicating

through memory

access and remote

direct memory

access

largely non-

coherent

accelerators and

multicores

communicating

through remote

direct memory

access

Sources: various vendors

Case Study 1: IBM POWER7 IH (BW)

62

On-line Storage

Near-line Storage

L-L

ink C

ab

les

Super Node(32 Nodes / 4 CEC)

P7 Chip (8 cores)

SMP node (32 cores)

Drawer (256 cores)

SuperNode (1024 cores)

Building Block

Blue Waters System

NPCF

Source: IBM Source: IBM/NCSA

POWER7 Core

63 Source: IBM Source: IBM/NCSA

POWER7 Chip (8 cores)

64

Base Technology

45 nm, 576 mm2

1.2 B transistors

Chip

8 cores

4 FMAs/cycle/core

32 MB L3 (private/shared)

Dual DDR3 memory

128 GiB/s peak bandwidth

(1/2 byte/flop)

Clock range of 3.5 – 4 GHz

Quad-chip MCM


MC

1M

C 0

8c uP

MC

1M

C0

8c uP

MC

0M

C1

8c uP

MC

0M

C1

8c uP

P7-0 P7-1

P7-3 P7-2

A

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Y X

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0M

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0M

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0M

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0M

C 1

Quad Chip Module (4 chips)

65

32 cores

32 cores*8 F/core*4 GHz = 1 TF

4 threads per core (max)

128 threads per package

4x32 MiB L3 cache

512 GB/s RAM BW (0.5 B/F)

800 W (0.8 W/F)


Adding a Network Interface (Hub)

66

DIM

M 1

5D

IMM

8D

IMM

9D

IMM

14

DIM

M 4

DIM

M 1

2D

IMM

13

DIM

M 5

DIM

M 1

1D

IMM

3D

IMM

2D

IMM

10

DIM

M 0

DIM

M 7

DIM

M 6

DIM

M 1

P7-IH Quad Block Diagram32w SMP w/ 2 Tier SMP Fabric, 4 chip Processor MCM + Hub SCM w/ On-Board Optics

MC

1

Mem

Mem

Mem

Mem

MC

0

Mem

Mem

8c uP

MC

1

Mem

Mem

Mem

Mem

MC

0

Mem

Mem

Mem

Mem

8c uP

7 Inter-Hub Board Level L-Buses

3.0Gb/s @ 8B+8B, 90% sus. peak

D0-D15 Lr0-Lr23

320 GB/s 240 GB/s

28x XMIT/RCV pairs@ 10 Gb/s

832

624

5+

5G

B/s

(6

x=

5+

1)

Hub Chip Module

22

+2

2G

B/s

164

Ll0

22

+2

2G

B/s

164

Ll1

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+2

2G

B/s

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Ll2

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2G

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Ll4

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+2

2G

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Ll5

22

+2

2G

B/s

164

Ll6

12x 12x

12x 12x

12x 12x

12x 12x

12x 12x

12x 12x

10

+1

0G

B/s

(1

2x=

10

+2

)

12x 12x 12x 12x

12x 12x 12x 12x

12x 12x 12x 12x

12x 12x 12x 12x

7+

7G

B/s

72

EG2

PC

Ie 6

1x

7+

7G

B/s

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EG1

PC

Ie 1

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7G

B/s

72

EG2

PC

Ie 8

x

MC

0

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Mem

Mem

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MC

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Mem

Mem

Mem

8c uP

MC

0

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Mem

Mem

Mem

MC

1

Mem

Mem

Mem

Mem

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Mem

P7-0 P7-1

P7-3 P7-2

A

B

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Y X

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0M

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0M

C 1

DIM

M 1

Mem

Mem

DIM

M 0

Mem

Mem

DIM

M 5Mem

Mem

DIM

M 4Mem

Mem

DIM

M 7

Mem

Mem

DIM

M 6

Mem

Mem

DIM

M 1

0

Mem

Mem

DIM

M 1

1

Mem

Mem

DIM

M 2

Mem

Mem

DIM

M 3

Mem

Mem

DIM

M 1

4Mem

Mem

DIM

M 1

5Mem

Mem

DIM

M 8Mem

Mem

DIM

M 9Mem

Mem

DIM

M 1

2Mem

Mem

DIM

M 1

3Mem

Mem

Connects QCM to PCI-e

Two 16x and one 8x PCI-e slot

Connects 8 QCM's via low

latency, high bandwidth,

copper fabric.

Provides a message passing

mechanism with very

high bandwidth

Provides the lowest possible

latency between 8 QCM's


1.1 TB/s POWER7 IH HUB

67

EI-

3 P

HY

s

Torrent

Diff PHYs

L lo

ca

l

HU

B T

o H

UB

Co

pp

er

Bo

ard

Wir

ing

L remote

4 Drawer Interconnect to Create a Supernode

Optical

LR

0 B

us

Op

tic

al

6x 6x

LR

23

Bu

s

Op

tic

al

6x 6x

LL0 Bus

Copper

8B

8B

8B

8B

LL1 Bus

Copper

8B

8B

LL2 Bus

Copper

8B

8B

LL4 Bus

Copper

8B

8B

LL5 Bus

Copper

8B

8B

LL6 Bus

Copper

8B

8B

LL3 Bus

Copper

Dif

f P

HY

s

PX

0 B

us

16

x

16

x

PC

I-E

IO P

HY

Ho

t P

lug

Ctl

PX

1 B

us

16

x

16

x

PC

I-E

IO P

HY

Ho

t P

lug

Ctl

PX

2 B

us

8x8x

PC

I-E

IO P

HY

Ho

t P

lug

Ctl

FS

I

FS

P1

-A

FS

I

FS

P1

-B

I2C

TP

MD

-A, T

MP

D-B

SV

IC

MD

C-A

SV

IC

MD

C-B

I2C

SE

EP

RO

M 1

I2C

SE

EP

RO

M 2

24

L remote

BusesHUB to QCM Connections

Address/Data

D B

us

Inte

rco

nn

ec

t o

f S

up

ern

od

es

Op

tic

al

D0 Bus

Optical

12x

12x

D15 Bus

Optical

12x

12x

16

D B

us

es

28

I2C

I2C_0 + Int

I2C_27 + Int

I2C

To

Op

tic

al

Mo

du

les

TO

D S

yn

c

8B

Z-B

us

8B

Z-B

us

TO

D S

yn

c

8B

Y-B

us

8B

Y-B

us

TO

D S

yn

c

8B

X-B

us

8B

X-B

us

TO

D S

yn

c

8B

W-B

us

8B

W-B

us

192 GB/s Host Connection

336 GB/s to 7 other local nodes

240 GB/s to local-remote nodes

320 GB/s to remote nodes

40 GB/s to general purpose I/O

cf. “The PERCS interconnect” @HotI’10

Hub Chip


P7 IH Drawer

68

First Level Interconnect

L-Local

HUB to HUB Copper Wiring

256 Cores

DCA-0 Connector (Top DCA)

DCA-1 Connector (Bottom DCA)

1st Level Local Interconnect (256 cores)

HUB

7

HUB

6

HUB

4

HUB

3

HUB

5

HUB

1

HUB

0

HUB

2

P

C

I

e

9

P

C

I

e

10

P

C

I

e

11

P

C

I

e

12

P

C

I

e

13

P

C

I

e

14

P

C

I

e

15

P

C

I

e

16

P

C

I

e

17

P1-C

17

-C1

P

C

I

e

1

P

C

I

e

2

P

C

I

e

3

P

C

I

e

4

P

C

I

e

5

P

C

I

e

6

P

C

I

e

7

P

C

I

e

8

Op

tica

l F

an-o

ut fr

om

HU

B M

od

ule

s

2,3

04

Fib

er

'L-L

ink'

64/40 Optical'D-Link'


P7-0

P7-2

P7-3P7-1

QCM 0

U-P1-M1

P7-0

P7-2

P7-3P7-1

QCM 1

U-P1-M2

P7-0

P7-2

P7-3P7-1

QCM 2

U-P1-M3

P7-0

P7-2

P7-3P7-1

QCM 3

U-P1-M4

P7-0

P7-2

P7-3P7-1

QCM 4

U-P1-M5

P7-0

P7-2

P7-3P7-1

QCM 5

U-P1-M6

P7-0

P7-2

P7-3P7-1

QCM 6

U-P1-M7

P7-0

P7-2

P7-3P7-1

QCM 7

U-P1-M8

P1-C

16

-C1

P1-C

15

-C1

P1-C

14

-C1

P1-C

13

-C1

P1-C

12

-C1

P1-C

11

-C1

P1-C

10

-C1

P1-C

9-C

1

P1-C

8-C

1

P1-C

7-C

1

P1-C

6-C

1

P1-C

5-C

1

P1-C

4-C

1

P1-C

3-C

1

P1-C

2-C

1

P1-C

1-C

1

N0

-DIM

M1

5N

0-D

IMM

14

N0

-DIM

M1

3N

0-D

IMM

12

N0

-DIM

M1

1N

0-D

IMM

10

N0

-DIM

M0

9N

0-D

IMM

08

N0-D

IMM

07

N0-D

IMM

06

N0-D

IMM

05

N0-D

IMM

04

N0-D

IMM

03

N0-D

IMM

02

N0-D

IMM

01

N0-D

IMM

00

N1

-DIM

M1

5N

1-D

IMM

14

N1

-DIM

M1

3N

1-D

IMM

12

N1

-DIM

M1

1N

1-D

IMM

10

N1

-DIM

M0

9N

1-D

IMM

08

N1-D

IMM

07

N1-D

IMM

06

N1-D

IMM

05

N1-D

IMM

04

N1-D

IMM

03

N1-D

IMM

02

N1-D

IMM

01

N1-D

IMM

00

N2

-DIM

M1

5N

2-D

IMM

14

N2

-DIM

M1

3N

2-D

IMM

12

N2

-DIM

M1

1N

2-D

IMM

10

N2

-DIM

M0

9N

2-D

IMM

08

N2-D

IMM

07

N2-D

IMM

06

N2-D

IMM

05

N2-D

IMM

04

N2-D

IMM

03

N2-D

IMM

02

N2-D

IMM

01

N2-D

IMM

00

N3

-DIM

M1

5N

3-D

IMM

14

N3

-DIM

M1

3N

3-D

IMM

12

N3

-DIM

M1

1N

3-D

IMM

10

N3

-DIM

M0

9N

3-D

IMM

08

N3-D

IMM

07

N3-D

IMM

06

N3-D

IMM

05

N3-D

IMM

04

N3-D

IMM

03

N3-D

IMM

02

N3-D

IMM

01

N3-D

IMM

00

N4

-DIM

M1

5N

4-D

IMM

14

N4

-DIM

M1

3N

4-D

IMM

12

N4

-DIM

M1

1N

4-D

IMM

10

N4

-DIM

M0

9N

4-D

IMM

08

N4-D

IMM

07

N4-D

IMM

06

N4-D

IMM

05

N4-D

IMM

04

N4-D

IMM

03

N4-D

IMM

02

N4-D

IMM

01

N4-D

IMM

00

N5

-DIM

M1

5N

5-D

IMM

14

N5

-DIM

M1

3N

5-D

IMM

12

N5

-DIM

M1

1N

5-D

IMM

10

N5

-DIM

M0

9N

5-D

IMM

08

N5-D

IMM

07

N5-D

IMM

06

N5-D

IMM

05

N5-D

IMM

04

N5-D

IMM

03

N5-D

IMM

02

N5-D

IMM

01

N5-D

IMM

00

N6

-DIM

M1

5N

6-D

IMM

14

N6

-DIM

M1

3N

6-D

IMM

12

N6

-DIM

M1

1N

6-D

IMM

10

N6

-DIM

M0

9N

6-D

IMM

08

N6-D

IMM

07

N6-D

IMM

06

N6-D

IMM

05

N6-D

IMM

04

N6-D

IMM

03

N6-D

IMM

02

N6-D

IMM

01

N6-D

IMM

00

N7

-DIM

M1

5N

7-D

IMM

14

N7

-DIM

M1

3N

7-D

IMM

12

N7

-DIM

M1

1N

7-D

IMM

10

N7

-DIM

M0

9N

7-D

IMM

08

N7-D

IMM

07

N7-D

IMM

06

N7-D

IMM

05

N7-D

IMM

04

N7-D

IMM

03

N7-D

IMM

02

N7-D

IMM

01

N7-D

IMM

00

• 8 nodes

• 32 chips

• 256 cores


POWER7 IH Drawer @ SC09 P7 IH Supernode

70

P7-IH Board Layout 2nd Level of Interconnect (1,024 cores)

4.6 TB/s

Bisection BWBW of 1150

10G-E ports



2nd

Level Interconnect (1,024 cores)

HUB

7

61x96mm

HUB

6

61x96mm

HUB

4

61x96mm

HUB

3

61x96mm

HUB

5

61x96mm

HUB

1

61x96mm

HUB

0

61x96mm

HUB

2

61x96mm

P

C

I

e

9

P

C

I

e

10

P

C

I

e

11

P

C

I

e

12

P

C

I

e

13

P

C

I

e

14

P

C

I

e

15

P

C

I

e

16

P

C

I

e

17

P

C

I

e

1

P

C

I

e

2

P

C

I

e

3

P

C

I

e

4

P

C

I

e

5

P

C

I

e

6

P

C

I

e

7

P

C

I

e

8

Op

tica

l Fa

n-o

ut fro

m

HU

B M

od

ule

s

2,3

04

Fib

er 'L

-Lin

k'


FSP/CLK-A


FSP/CLK-B

P7-0

P7-2

P7-3P7-1

QCM 0

P7-0

P7-2

P7-3P7-1

QCM 1

P7-0

P7-2

P7-3P7-1

QCM 2

P7-0

P7-2

P7-3P7-1

QCM 3

P7-0

P7-2

P7-3P7-1

QCM 4

P7-0

P7-2

P7-3P7-1

QCM 5

P7-0

P7-2

P7-3P7-1

QCM 6

P7-0

P7-2

P7-3P7-1

QCM 7



2nd


HUB

7

61x96mm

HUB

6

61x96mm

HUB

4

61x96mm

HUB

3

61x96mm

HUB

5

61x96mm

HUB

1

61x96mm

HUB

0

61x96mm

HUB

2

61x96mm

P

C

I

e

9

P

C

I

e

10

P

C

I

e

11

P

C

I

e

12

P

C

I

e

13

P

C

I

e

14

P

C

I

e

15

P

C

I

e

16

P

C

I

e

17

P

C

I

e

1

P

C

I

e

2

P

C

I

e

3

P

C

I

e

4

P

C

I

e

5

P

C

I

e

6

P

C

I

e

7

P

C

I

e

8

Op

tica

l Fa

n-o

ut fro

m

HU

B M

od

ule

s

2,3

04

Fib

er 'L

-Lin

k'


FSP/CLK-A


FSP/CLK-B

P7-0

P7-2

P7-3P7-1

QCM 0

P7-0

P7-2

P7-3P7-1

QCM 1

P7-0

P7-2

P7-3P7-1

QCM 2

P7-0

P7-2

P7-3P7-1

QCM 3

P7-0

P7-2

P7-3P7-1

QCM 4

P7-0

P7-2

P7-3P7-1

QCM 5

P7-0

P7-2

P7-3P7-1

QCM 6

P7-0

P7-2

P7-3P7-1

QCM 7



2nd


HUB

761x96mm

HUB

661x96mm

HUB

461x96mm

HUB

361x96mm

HUB

561x96mm

HUB

161x96mm

HUB

061x96mm

HUB

261x96mm

P

C

I

e

9

P

C

I

e

10

P

C

I

e

11

P

C

I

e

12

P

C

I

e

13

P

C

I

e

14

P

C

I

e

15

P

C

I

e

16

P

C

I

e

17

P

C

I

e

1

P

C

I

e

2

P

C

I

e

3

P

C

I

e

4

P

C

I

e

5

P

C

I

e

6

P

C

I

e

7

P

C

I

e

8

Op

tica

l F

an-o

ut fr

om

HU

B M

od

ule

s

2,3

04

Fib

er

'L-L

ink'


FSP/CLK-A


FSP/CLK-B

P7-0

P7-2

P7-3P7-1

QCM 0

P7-0

P7-2

P7-3P7-1

QCM 1

P7-0

P7-2

P7-3P7-1

QCM 2

P7-0

P7-2

P7-3P7-1

QCM 3

P7-0

P7-2

P7-3P7-1

QCM 4

P7-0

P7-2

P7-3P7-1

QCM 5

P7-0

P7-2

P7-3P7-1

QCM 6

P7-0

P7-2

P7-3P7-1

QCM 7



2nd


HUB

761x96mm

HUB

661x96mm

HUB

461x96mm

HUB

361x96mm

HUB

561x96mm

HUB

161x96mm

HUB

061x96mm

HUB

261x96mm

P

C

I

e

9

P

C

I

e

10

P

C

I

e

11

P

C

I

e

12

P

C

I

e

13

P

C

I

e

14

P

C

I

e

15

P

C

I

e

16

P

C

I

e

17

P

C

I

e

1

P

C

I

e

2

P

C

I

e

3

P

C

I

e

4

P

C

I

e

5

P

C

I

e

6

P

C

I

e

7

P

C

I

e

8

Op

tica

l F

an-o

ut fr

om

HU

B M

od

ule

s

2,3

04

Fib

er

'L-L

ink'


FSP/CLK-A


FSP/CLK-B

P7-0

P7-2

P7-3P7-1

QCM 0

P7-0

P7-2

P7-3P7-1

QCM 1

P7-0

P7-2

P7-3P7-1

QCM 2

P7-0

P7-2

P7-3P7-1

QCM 3

P7-0

P7-2

P7-3P7-1

QCM 4

P7-0

P7-2

P7-3P7-1

QCM 5

P7-0

P7-2

P7-3P7-1

QCM 6

P7-0

P7-2

P7-3P7-1

QCM 7

Second Level Interconnect

Optical ‘L-Remote’ Links from HUB

4 drawers

1,024 Cores

L-L

ink C

ab

les

Super Node(32 Nodes / 4 CEC)


1. Chip

16 cores

2. Module

Single Chip 4. Node Card

32 Compute Cards,

Optical Modules, Link Chips, Torus

5a. Midplane

16 Node Cards

6. Rack

2 Midplanes

1, 2 or 4 I/O Drawers

7. System

20PF/s

3. Compute Card

One single chip module,

16 GB DDR3 Memory

5b. I/O Drawer

8 I/O Cards

8 PCIe Gen2 slots

Case Study 2: IBM Blue Gene/Q packaging

Source: IBM, SC10

16

16 16

512

8192

16384 ~2 Mio

© Markus Püschel Computer Science

Blue Gene/Q Compute chip 360 mm² Cu-45 technology (SOI)

~ 1.47 B transistors

16 user + 1 service processors plus 1 redundant processor all processors are symmetric each 4-way multi-threaded 64 bits PowerISA™

1.6 GHz L1 I/D cache = 16kB/16kB L1 prefetch engines each processor has Quad FPU (4-wide double precision, SIMD) peak performance 204.8 GFLOPS@55W

Central shared L2 cache: 32 MB

eDRAM multiversioned cache/transactional

memory/speculative execution. supports atomic ops

Dual memory controller

16 GB external DDR3 memory 1.33 Gb/s 2 * 16 byte-wide interface (+ECC)

Chip-to-chip networking

Router logic integrated into BQC chip.

System-on-a-Chip design : integrates processors,

memory and networking logic into a single chip

Source: IBM, PACT’11

Blue Gene/Q Network

73

On-chip external network Message Unit Torus Switch Serdes Everything!

Only 55-60 W per node Top of Green500 and

GreenGraph500

Source: IBM, PACT’11

Case Study 3: Cray Cascade (XC30)

Biggest current installation at CSCS!

>2k nodes

Standard Intel x86 Sandy Bridge Server-class CPUs

74

Source: Bob Alverson, Cray

Cray Cascade Network Topology

All-to-all connection among groups (“blue network”)

What does that remind you of?

75

Source: Bob Alverson, Cray


Motivate you!





Basic overview of

Programming models

Some examples

Architectures

Some case-studies


76

DPHPC Lecture

You will most likely not have access to the largest machines

But our desktop/laptop will be a “large machine” soon

HPC is often seen as “Formula 1” of computing (architecture experiments)

DPHPC will teach you concepts!

Enable to understand and use all parallel architectures

From a quad-core mobile phone to the largest machine on the planet!

MCAPI vs. MPI – same concepts, different syntax

No particular language (but you should pick/learn one for your project!)

Parallelism is the future:

77

Related classes in the SE focus

263-2910-00L Program Analysis http://www.srl.inf.ethz.ch/pa.php Spring 2015 Lecturer: Prof. M. Vechev

263-2300-00L How to Write Fast Numerical Code http://www.inf.ethz.ch/personal/markusp/teaching/263-2300-ETH-spring14/course.html Spring 2015 Lecturer: Prof. M. Pueschel

This list is not exhaustive!

78

DPHPC Overview

79

Documents

Goals of this lecture - SPCL · Goals of this lecture Motivate you! ... Source: Can we do this today? 5 Source: Blue Waters, ~13 PF (2012)