Embed Size (px)
Citation preview
TECHNICAL WHITE PAPER – SEPTEMBER 2016
WINDOWS 10 OPTIMIZATION TEST RESULTSView in VMware Horizon 7
T E C H N I C A L W H I T E PA P E R | 2
WINDOWS 10 OPTIMIZATION TEST RESULTS
Table of Contents
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3
Audience. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Horizon 7 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Testing Details . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3
VMware OSOT Fling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Login VSI . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Methodology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Hardware . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Optimizations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Main Optimizations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Additional Optimizations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Benchmark Test Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Optimization Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
vCenter Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
About the Author . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
T E C H N I C A L W H I T E PA P E R | 3
WINDOWS 10 OPTIMIZATION TEST RESULTS
IntroductionThis paper presents crucial test results that demonstrate the benefits of the VMware Operating System Optimization Tool (OSOT) Fling for View desktops in VMware Horizon® 7. It compares optimized and non-optimized versions of Windows 10 and optimized Windows 7, highlighting the resources needed to upgrade to Windows 10 from Windows 7 in a virtualized environment. Additional optimizations not handled by the Optimization Fling or described in the VMware Windows Operating System Optimization Tool Guide are also included.
AudienceThis paper was written specifically for data center administrators and IT personnel who want to upgrade from Windows 7 to Windows 10 or to optimize Windows 10 operating systems for View virtual desktops in Horizon 7. Architects and others interested in Horizon 7 or in improving the performance of Windows desktops may also find it useful.
Horizon 7 Horizon 7 provides centralized image management for virtualized or hosted desktops and applications, which can be delivered to end users through a single platform. Desktop and application services—including RDS-hosted apps, packaged apps with VMware ThinApp®, SaaS apps, and even virtualized apps from Citrix—can all be accessed from a single, unified workspace.
Horizon 7 supports both Windows and Linux-based desktops, including RHEL, Ubuntu, CentOS, and NeoKylin. This paper, however, focuses on Windows 7 and Windows 10, especially the performance differences between optimized and non-optimized versions.
Testing Details The following sections discuss the testing performed, including the VMware OSOT Fling, additional optimizations, testing methods, hardware, and results.
VMware OSOT FlingThe free OSOT Fling makes it easy to apply configuration settings to desktops and servers. It includes settings to optimize the following Windows operating systems for both desktops and servers that reside in the data center and in the cloud:
• Windows 7
• Windows 8
• Windows 8.1
• Windows 10
• Windows Server 2008 (including R2)
• Windows Server 2012 (including R2)
The OSOT Fling optimizes RDSH servers for VMware Horizon 6, Horizon 7, and VMware Horizon Air™.
T E C H N I C A L W H I T E PA P E R | 4
WINDOWS 10 OPTIMIZATION TEST RESULTS
Login VSIAll performance testing documented in this paper used the Login VSI benchmarking tool, the industry-standard load-testing solution for centralized virtualized desktop environments. Login VSI measures the total response time of several specific user operations performed within a desktop workload in a scripted loop. The baseline measures the response time, in milliseconds (ms), of specific operations performed in the desktop workload.
The Login VSI test suite defines several types of workloads to simulate various types of users, as shown in Table 1.
WORKLOAD PROFILE WEIGHT vCPU APPS VIDEO
Task Worker Light 1 2–3 No
Office Worker Medium 1 4–6 240p
Knowledge Worker Medium 2 4–7 360p
Power User Heavy 2–4 5–9 720p
Table 1: Login VSI Workloads
For the tests reported in this paper, we used the Knowledge Worker workload, which simulates how resources are used in VDI environments that use two virtual CPUs in their virtual machines. The Knowledge Worker workload includes the following applications:
• Microsoft Outlook
• Microsoft Internet Explorer
• Microsoft Word
• Adobe Acrobat Reader
• Microsoft PowerPoint
• Microsoft Excel
• Adobe Flash Player
• Java 7
• FreeMind
• Login VSI photo viewer
• Doro PDF Writer
The Login VSI Benchmark mode predefines and constrains the launch window to 2880 seconds (48 minutes). This gives a normalized baseline to compare all tests and allows for the workload to complete a full 48-minute cycle. There is only one phase to this profile. A user starts a remote desktop session on a VM and begins the workload. At the end of the workload cycle, a benchmark, or baseline, score is calculated. The lower the score, the better the result or performance.
T E C H N I C A L W H I T E PA P E R | 5
WINDOWS 10 OPTIMIZATION TEST RESULTS
MEASUREMENT ID MEASUREMENT ACTION
MEASUREMENT ACTION DETAILED
MEASURES-RELATED RESOURCE
WSLD Start Microsoft Word and load a random document.
Start and load a local random document file from the content pool.
CPU, RAM, and I/O
NSLD Start VSI Notepad and load a random document.
Start and load a local random text file from the content pool.
CPU and I/O
WFO Open a file in VSI Notepad.
Ctrl+O CPU, RAM, and I/O
NFP Open Print in VSI Notepad.
Ctrl+P CPU
ZHC Compress files with high compression.
Compress a local random PST file from the content pool (5 MB).
CPU
ZNC Compress files with no compression.
Compress a local random PST file from the content pool (5 MB).
I/O
Table 2: Actions Taken During a Knowledge Worker Test Session
We took a methodical approach to all test operations. Tests were performed in an environment where the only services and servers used were those needed by Login VSI. No core infrastructure servers, such as Active Directory and SQL servers, were in use by any other applications.
After deploying all components and applications required for the Login VSI workload on each desktop, we conducted functional validation, using a very simple test methodology.
Methodology To begin, we ran a baseline Login VSI Knowledge Worker benchmark test, with the required applications, to provide a simple baseline showing performance and scale information for a traditional, non-optimized Windows 7 desktop. Next, we ran the same test on an optimized Windows 7 desktop to see the difference in baseline performance. We then ran the Login VSI Knowledge Worker test on a Windows 7 optimized desktop, Windows 10 non-optimized desktop, and Windows 10 optimized desktop.
The measured operations in these benchmarks touch different subsystems, such as CPU (user and kernel), memory, disk, the OS, the application, and print. The operations typically execute quickly. When these operations consistently take a long time to execute, the system becomes saturated because of excessive queuing, and the average response times escalate. This effect is reflected in the baseline score and is also visible to end users.
For each desktop, we ran the test three times to ensure consistency.
T E C H N I C A L W H I T E PA P E R | 6
WINDOWS 10 OPTIMIZATION TEST RESULTS
HardwareEach host used for testing was a Dell PowerEdge R730 with 28 cores at 2.29 GHz with 262 GB of memory, and an EMC XtremIO all-flash array for storage.
Table 3: Host Specifications
The XtremIO storage array is an all-flash system, based on a scale-out architecture that uses building blocks called X-Bricks, which can be clustered to increase performance and capacity as required. It is controlled by a standalone, dedicated Linux-based server, called the XtremIO Management Server (XMS). An XMS host, which can be either a physical or a virtual server, can manage multiple XtremIO clusters. An array continues operating if it is disconnected from the XMS, but cannot be configured or monitored.
OptimizationsWe used all the available optimizations in the VMware OSOT Fling. You can choose not to apply all optimizations, but your results may vary. If you do not apply all of the optimizations recommended, at least apply the main optimizations.
Main Optimizations
These are some of the basic optimizations that were applied:
• Adjust Windows for best performance.
• Turn off all unneeded visual effects.
• Set unused services to either Manual or Disabled.
• Disable programs at startup.
• Use High Performance Power plan.
• Speed up the menu show time.
T E C H N I C A L W H I T E PA P E R | 7
WINDOWS 10 OPTIMIZATION TEST RESULTS
As shown in Figure 1, however, far more optimizations are applied by the VMware OSOT Fling.
Figure 1: Some Optimizations Applied by OSOT Fling
Additional Optimizations
Whether you choose to use the OSOT Fling or not, the following optional optimizations are strongly suggested:
• Install the latest Windows updates.
• Enable write caching for storage devices.
• Move the page file to separate disk.
• Uninstall any unneeded or unused programs.
• Disable or uninstall all Internet Explorer add-ons and toolbars.
• Keep the index enabled and updated (or disable the index).
• Change how long notifications stay open.
• Adjust privacy settings to not share.
• Speed up Windows shutdown time.
T E C H N I C A L W H I T E PA P E R | 8
WINDOWS 10 OPTIMIZATION TEST RESULTS
You can set and adjust the following values for how long Windows waits for hung programs and other programs to save data and close before shutting down:
– AutoEndTasks
– HungAppTimeout
– WaitToKillAppTimeout
– WaitToKillServiceTimeout
For each host, make sure the BIOS Power Management Policy settings are set for High performance.
Figure 2: BIOS Power Management Settings
Benchmark Test ResultsWe used the Login VSI 4.0 tool to run a representative workload on virtual desktops running each of the operating system versions to get a benchmark or baseline score.
VSIbase is a baseline score that reflects the response time of specific operations performed in the desktop workload when there is little or no stress on the system. A low baseline indicates a better user experience, resulting from applications responding faster in the environment.
VSIBASE SCORE (IN MICROSECONDS) PERFORMANCE
0–99 ms Excellent
800–1399 ms Very Good
1400–1999 ms Good
1999–9999 ms Reasonable/Poor
Table 4: VSIbase Scoring for This Test Environment
T E C H N I C A L W H I T E PA P E R | 9
WINDOWS 10 OPTIMIZATION TEST RESULTS
For this environment, a score of 1627 was considered a good score. A score less than 1399 is a very good score compared to our baseline and shows better performance.
Optimization Results With our testing we saw an 18–25 percent increase in performance with Windows 10 optimized as compared to Windows 10 non-optimized and Windows 7 optimized, indicating better performance and a better overall user experience.
Figure 3: Graph of LSI Benchmark Scores
WINDOWS 7 OPTIMIZED WINDOWS 10 NON-OPTIMIZED WINDOWS 10 OPTIMIZED
Test run 1: 1610 ms Test run 1: 1685 ms Test run 1: 1311 ms
Test run 2: 1605 ms Test run 2: 1609 ms Test run 2: 1310 ms
Test run 3: 1624 ms Test run 3: 1633 ms Test run 3: 1231 ms
Table 5: Optimization Test Results
T E C H N I C A L W H I T E PA P E R | 1 0
WINDOWS 10 OPTIMIZATION TEST RESULTS
vCenter Data The vCenter data below also confirms that Windows 10 optimized had considerably less CPU usage, memory usage, and disk latency than Windows 10 non-optimized. CPU average usage was approximately 30 percent lower, and disk latency was lower by a little more than 50 percent. Although Windows 10 optimized and Windows 7 optimized showed similar results, the overall CPU, memory, and disk latency were lower on the Windows 10 optimized virtual machine. The Windows 7 optimized VM also had a considerably longer login time, which contributed to its higher (that is, worse) benchmark scores. The vCenter data scores are shown in the following graphs:
2000
10:00 PM
Performance Chart Legend
10:05 PM 10:15 PM10:10 PM 10:20 PM 10:25 PM 10:30 PM 10:35 PM 10:40 PM 10:45 PM 10:55 PM10:50 PM
1500
MH
z
Percent
1000
500
0
100
75
50
25
0
Key Object MeasurementUsage in MHzUsage in MHzUsage Usage in MHz
Win7-VSI-Opt0Win7-VSI-Opt1
RollupAverageAverageAverageAverage
UnitsMHzMHzPercentMHz
Latest249
0.49
Maximum1764897
28.83792
Minimum249
0.49
Average478.961239.478
7.832190.239
Time
Figure 4: Windows 7 Optimized CPU Utilization
T E C H N I C A L W H I T E PA P E R | 1 1
WINDOWS 10 OPTIMIZATION TEST RESULTS
5000000
10:05 PM
Performance Chart Legend
10:10 PM 10:15 PM 10:20 PM 10:25 PM 10:30 PM 10:35 PM 10:40 PM 10:45 PM 10:50 PM 10:55 PM 11:00 PM
3750000
Kilobytes
2500000
1250000
0
Key Object MeasurementGrantedActiveBalloonConsumed
Win7-VSI-OptWin7-VSI-OptWin7-VSI-OptWin7-VSI-Opt
RollupAverageAverageAverageAverage
UnitsKilobytesKilobytesKilobytesKilobytes
Latest41308161468004
04130816
Maximum41308164110416
04130816
Minimum3960896754972
03960892
Average4090785.01411381.2
04090784.5
Time
Figure 5: Windows 7 Optimized Memory Utilization
10
10:05 PM
Performance Chart Legend
Time10:10 PM 10:15 PM 10:20 PM 10:25 PM 10:30 PM 10:35 PM 10:40 PM 10:45 PM 10:50 PM 10:55 PM 11:00 PM
7.5
Millisecond
5
2.5
0
Key Object MeasurementHighest latencyWin7-VSI-Opt
RollupLatest
UnitsMillisecond
Latest0
Maximum8
Minimum0
Average0.467
Figure 6: Windows 7 Optimized Disk Latency
T E C H N I C A L W H I T E PA P E R | 1 2
WINDOWS 10 OPTIMIZATION TEST RESULTS
6000
4:20 PM4:15 PM
Performance Chart Legend
4:25 PM 4:30 PM 4:35 PM 4:40 PM 4:45 PM 4:50 PM 4:55 PM 5:00 PM 5:05 PM 5:10 PM
4500
MH
z
Percent
3000
1500
0
100
75
50
25
0
Key Object MeasurementUsage in MHzUsage in MHzUsage in MHzUsage
Win10-VSI10Win10-VSI
RollupAverageAverageAverageAverage
UnitsMHzMHzMHzPercent
Latest546267268
8.93
Maximum563128132719
92.05
Minimum963355
1.57
Average1026.589484.161490.11716.784
Time
Figure 7: Windows 10 Non-Optimized CPU Utilization
4000000
4:20 PM
Performance Chart Legend
4:25 PM 4:30 PM 4:35 PM 4:40 PM 4:45 PM 4:50 PM 4:55 PM 5:00 PM 5:05 PM 5:10 PM 5:15 PM
3000000
Kilobytes
2000000
1000000
0
Key Object MeasurementGrantedActiveConsumedBalloon
Win10-VSIWin10-VSIWin10-VSIWin10-VSI
RollupAverageAverageAverageAverage
UnitsKilobytesKilobytesKilobytesKilobytes
Latest398744012163483987436
0
Maximum398744039007003987436
0
Minimum1834980880800
18349800
Average3419297.81439343.43419274.6
0
TimeTime
Figure 8: Windows 10 Non-Optimized Memory Utilization
T E C H N I C A L W H I T E PA P E R | 1 3
WINDOWS 10 OPTIMIZATION TEST RESULTS
6
4:20 PMTime
Performance Chart Legend
4:25 PM 4:30 PM 4:35 PM 4:40 PM 4:45 PM 4:50 PM 4:55 PM 5:00 PM 5:05 PM 5:10 PM 5:15 PM
4.5
Millisecond
3
1.5
0
Key Object MeasurementHighest latencyWin10-VSI
RollupLatest
UnitsMillisecond
Latest0
Maximum5
Minimum0
Average0.739
Figure 9: Windows 10 Non-Optimized Disk Latency
4000
5:20 PM
Performance Chart Legend
5:25 PM 5:30 PM 5:35 PM 5:40 PM 5:45 PM 5:50 PM 5:55 PM 6:00 PM 6:05 PM 6:10 PM 6:15 PM
3000
MH
z
Percent
2000
1000
0
100
75
50
25
0
Key Object MeasurementUsage in MHzUsage in MHzUsage in MHzUsage
Win10-VSI-Opt01Win10-VSI-Opt
RollupAverageAverageAverageAverage
UnitsMHzMHzMHzPercent
Latest5932992769.7
Maximum359817161761
58.82
Minimum6100
1.01
Average677.439328.402317.57511.076
Time
Figure 10: Windows 10 Optimized CPU Utilization
T E C H N I C A L W H I T E PA P E R | 1 4
WINDOWS 10 OPTIMIZATION TEST RESULTS
4000000
5:20 PM
Performance Chart Legend
5:25 PM 5:30 PM 5:35 PM 5:40 PM 5:45 PM 5:50 PM 5:55 PM 6:00 PM 6:05 PM 6:10 PM 6:15 PM
3000000
Kilobytes
2000000
1000000
0
Key Object MeasurementGrantedActiveConsumedBalloon
Win10-VSI-OptWin10-VSI-OptWin10-VSI-OptWin10-VSI-Opt
RollupAverageAverageAverageAverage
UnitsKilobytesKilobytesKilobytesKilobytes
Latest306790410485763067804
0
Maximum348979239007003489792
0
Minimum1200044
3355441200044
0
Average2745141.71346369.72745068.8
0
Time
Figure 11: Windows 10 Optimized Memory Utilization
6
5:20 PM
Performance Chart Legend
Time5:25 PM 5:30 PM 5:35 PM 5:40 PM 5:45 PM 5:50 PM 5:55 PM 6:00 PM 6:05 PM 6:10 PM 6:15 PM
4.5
Millisecond
3
1.5
0
Key Object MeasurementHighest latencyWin10-VSI-Opt
RollupLatest
UnitsMillisecond
Latest2
Maximum4
Minimum0
Average0.339
Figure 12: Windows 10 Optimized Disk Latency
T E C H N I C A L W H I T E PA P E R | 1 5
WINDOWS 10 OPTIMIZATION TEST RESULTS
ConclusionWindows 10 virtual desktops showed a considerable improvement in performance—around 30 percent—when optimized with the OSOT Fling. Non-optimized Windows 10 desktops showed a similar performance improvement compared to optimized Window 7 desktops, so the contrast between Windows 7, whether optimized or not, and Windows 10 optimized with OSOT is truly dramatic. The OSOT Fling also reduced the amount of memory and storage I/O used by each desktop. A reduction of this magnitude can improve resource utilization—or resource recovery—by enabling each host to support a larger number of virtual desktops. We did not calculate or predict the cost or resource savings because these must vary for each implementation, but a performance improvement in the reported range should be reason enough to use the OSOT Fling.
T E C H N I C A L W H I T E PA P E R | 1 6
WINDOWS 10 OPTIMIZATION TEST RESULTS
About the AuthorChris White is an Architect on the VMware End-User-Computing Technical-Marketing Center of Excellence team. He wishes to thank Gary Sloane, VMware Consulting Editor, for many suggestions and contributions to this paper.
VMware, Inc. 3401 Hillview Avenue Palo Alto CA 94304 USA Tel 877-486-9273 Fax 650-427-5001 www .vmware .comCopyright © 2016 VMware, Inc. All rights reserved. This product is protected by U.S. and international copyright and intellectual property laws. VMware products are covered by one or more patents listed at http://www.vmware.com/go/patents. VMware is a registered trademark or trademark of VMware, Inc. in the United States and/or other jurisdictions. All other marks and names mentioned herein may be trademarks of their respective companies. Item No: 4687-WP-APPVOLUMESREVIEWERSGUIDE-USLET-20160915-WEB 9/16
![[MS-CANVAS2D]: Microsoft Edge / Internet Explorer HTML ...M… · Microsoft Edge / Internet Explorer HTML Canvas 2D Context Standards Support Document Intellectual Property Rights](https://img.pdfslide.us/doc/110x75/5f928ae35806ed7d8407cf1b/ms-canvas2d-microsoft-edge-internet-explorer-html-m-microsoft-edge-.jpg)
![[MS-POINTER]: Microsoft Edge / Internet Explorer Pointer ... · [MS-CSS21E] Microsoft Corporation, "Internet Explorer Extensions to Cascading Style Sheets (CSS) 2.1 and DOM Level](https://img.pdfslide.us/doc/110x75/5f094d727e708231d4262e49/ms-pointer-microsoft-edge-internet-explorer-pointer-ms-css21e-microsoft.jpg)
![[MS-INDEXDB]: Microsoft Edge / Internet Explorer Indexed ... · Windows Internet Explorer 10 Internet Explorer 11 Internet Explorer 11 for Windows 10 Microsoft Edge Each browser version](https://img.pdfslide.us/doc/110x75/5f6247bba7b60d5e1c2cdd91/ms-indexdb-microsoft-edge-internet-explorer-indexed-windows-internet-explorer.jpg)
![[MS-HTML5]: Microsoft Edge / Internet Explorer HTML5 ... · 1 / 173 [MS-HTML5] - v20170314 Microsoft Edge / Internet Explorer HTML5 Standards Support Document Copyright © 2017 Microsoft](https://img.pdfslide.us/doc/110x75/5e9a97a51fd59a08fc61c899/ms-html5-microsoft-edge-internet-explorer-html5-1-173-ms-html5-v20170314.jpg)
![[MS-INDEXDB]: Microsoft Edge / Internet Explorer …interoperability.blob.core.windows.net/web/MS-INDEXDB/...Microsoft Edge / Internet Explorer Indexed Database API Standards Support](https://img.pdfslide.us/doc/110x75/5ab50c057f8b9a6e1c8c72c0/ms-indexdb-microsoft-edge-internet-explorer-edge-internet-explorer-indexed.jpg)
![[MS-HTML5]: Microsoft Edge / Internet Explorer …MS-HTML5].pdfMicrosoft Edge / Internet Explorer HTML5 ... Microsoft Edge / Internet Explorer HTML5 ... Microsoft Edge / Internet Explorer](https://img.pdfslide.us/doc/110x75/5ad35ecf7f8b9aff738de6d3/ms-html5-microsoft-edge-internet-explorer-ms-html5pdfmicrosoft-edge-.jpg)
![[MS-HTML5]: Microsoft Edge / Internet Explorer HTML5 ...interoperability.blob.core.windows.net/web/MS-HTML5/[MS-HTML5].pdf · Microsoft Edge / Internet Explorer HTML5 Standards Support](https://img.pdfslide.us/doc/110x75/5a903bb67f8b9a4a268e1ade/ms-html5-microsoft-edge-internet-explorer-html5-ms-html5pdfmicrosoft.jpg)
