In testing we can see many common performance problems .the main aspects causing performance degradation are speed, response time, loading time and poor scalability. Below are the main performance issues we can observe in our daily testing.
High CPU utilization :You can figure out this issue very common.you can see by adding the counters process time and % Processor Time.you can see which process is causing high CPU for the application.
Memory Leak(high memory utilization):a memory leak is loss of available memory when a program fails to return memory that it has obtained for temporary use. As a result, the available memory for that application drains out completely and the programs can no longer function. For a program that is frequently opened or that runs continuously, even a very small memory leak can eventually cause the program to terminate. A memory leak is the result of a programming bug, so it is very important to test it during development phase.
Network utilization:
Bandwidth utilization is a well-known, but not a well-understood network statistic. There are a couple factors to take into account when monitoring bandwidth utilization.
The first factor is understanding the difference between a bandwidth utilization statistic from a single segment and an aggregate of segments. Administrators often want to know, or are asked the question, "What is the bandwidth utilization of our network?" The problem is that even on the most basic of networks, this is almost an impossible statistic to determine.
This is because that even on a flat network, there are typically multiple segments, sites, and links that cannot realistically be totaled. For example, if you have 10 segments that you have gathered bandwidth utilization information on for a number of weeks, averaging that data will result in a meaningless number that does not reflect any real statistic. For instance, if nine of the segments have an average utilization of 10 percent, and one segment reaches 95 percent utilization, then "Network Utilization" would be 18.5 percent. This number is of no value because it hides the problem of the single site and increases the utilization of other sites. However, if each segment is monitored separately, the administrator will be able to stay on top of the network, identifying and resolving issues before they even become a problem. Proactive utilization management can save any company significant time and money.
Operating System limitations
Disk usage: It is also one of the common issue factor
High Loading time:Load time is normally the initial time it takes an application to start. This should generally be kept to a minimum. While some applications are impossible to make load in under a minute, Load time should be kept under a few seconds if possible.
Speed is the important attributes of an application. A slow running application will lose potential users. Performance testing is done to make sure an app runs fast enough to keep a user’s attention and interest.
High Response time:Response time is the time it takes from when a user inputs data into the application until the application outputs a response to that input. Generally this should be very quick. Again if a user has to wait too long, the user may not wait that much time.he can give up with the high response time.
Poor scalability :A software product suffers from poor scalability when it cannot handle the expected number of users or when it does not accommodate a wide enough range of users. Load testing should be done to be certain the application can handle the anticipated number of users.
High CPU utilization :You can figure out this issue very common.you can see by adding the counters process time and % Processor Time.you can see which process is causing high CPU for the application.
Memory Leak(high memory utilization):a memory leak is loss of available memory when a program fails to return memory that it has obtained for temporary use. As a result, the available memory for that application drains out completely and the programs can no longer function. For a program that is frequently opened or that runs continuously, even a very small memory leak can eventually cause the program to terminate. A memory leak is the result of a programming bug, so it is very important to test it during development phase.
Network utilization:
Bandwidth utilization is a well-known, but not a well-understood network statistic. There are a couple factors to take into account when monitoring bandwidth utilization.
The first factor is understanding the difference between a bandwidth utilization statistic from a single segment and an aggregate of segments. Administrators often want to know, or are asked the question, "What is the bandwidth utilization of our network?" The problem is that even on the most basic of networks, this is almost an impossible statistic to determine.
This is because that even on a flat network, there are typically multiple segments, sites, and links that cannot realistically be totaled. For example, if you have 10 segments that you have gathered bandwidth utilization information on for a number of weeks, averaging that data will result in a meaningless number that does not reflect any real statistic. For instance, if nine of the segments have an average utilization of 10 percent, and one segment reaches 95 percent utilization, then "Network Utilization" would be 18.5 percent. This number is of no value because it hides the problem of the single site and increases the utilization of other sites. However, if each segment is monitored separately, the administrator will be able to stay on top of the network, identifying and resolving issues before they even become a problem. Proactive utilization management can save any company significant time and money.
Operating System limitations
Memory and Address Space Limits
The following table specifies the limits on memory and address space for supported releases of Windows. Unless otherwise noted, the limits in this table apply to all supported releases.
| Memory type | Limit in on X86 | Limit in 64-bit Windows |
|---|---|---|
User-mode virtual address space for each 32-bit process
|
2 GB
Up to 3 GB withIMAGE_FILE_LARGE_ADDRESS_AWARE and 4GT
|
2 GB withIMAGE_FILE_LARGE_ADDRESS_AWAREcleared (default)
4 GB withIMAGE_FILE_LARGE_ADDRESS_AWAREset
|
User-mode virtual address space for each 64-bit process
|
Not applicable
|
With IMAGE_FILE_LARGE_ADDRESS_AWAREset (default):
x64: 8 TB
Intel Itanium-based systems: 7 TB
Windows 8.1 and Windows Server 2012 R2: 128 TB
2 GB withIMAGE_FILE_LARGE_ADDRESS_AWAREcleared
|
Kernel-mode virtual address space
|
2 GB
From 1 GB to a maximum of 2 GB with 4GT
|
8 TB
Windows 8.1 and Windows Server 2012 R2: 128 TB
|
Paged pool
|
384 GB or system commit limit, whichever is smaller.
Windows 8.1 and Windows Server 2012 R2: 15.5 TB or system commit limit, whichever is smaller.
Windows Server 2008 R2, Windows 7, Windows Server 2008, and Windows Vista: Limited by available kernel-mode virtual address space. Starting with Windows Vista with Service Pack 1 (SP1), the paged pool can also be limited by the PagedPoolLimit registry key value.
Windows Home Server and Windows Server 2003: 530 MB
Windows XP: 490 MB
|
384 GB or system commit limit, whichever is smaller
Windows 8.1 and Windows Server 2012 R2: 15.5 TB or system commit limit, whichever is smaller.
Windows Server 2008 R2, Windows 7, Windows Server 2008, and Windows Vista: 128 GB or system commit limit, whichever is smaller
Windows Server 2003 and Windows XP: Up to 128 GB depending on configuration and RAM.
|
Nonpaged pool
|
75% of RAM or 2 GB, whichever is smaller.
Windows 8.1 and Windows Server 2012 R2: RAM or 16 TB, whichever is smaller (address space is limited to 2 x RAM).
Windows Vista: Limited only by kernel mode virtual address space and physical memory. Starting with Windows Vista with SP1, the nonpaged pool can also be limited by the NonPagedPoolLimit registry key value.
Windows Home Server, Windows Server 2003, and Windows XP: 256 MB, or 128 MB with 4GT.
|
RAM or 128 GB, whichever is smaller (address space is limited to 2 x RAM)
Windows 8.1 and Windows Server 2012 R2: RAM or 16 TB, whichever is smaller (address space is limited to 2 x RAM).
Windows Server 2008 R2, Windows 7, and Windows Server 2008: 75% of RAM up to a maximum of 128 GB
Windows Vista: 40% of RAM up to a maximum of 128 GB.
Windows Server 2003 and Windows XP: Up to 128 GB depending on configuration and RAM.
|
System cache virtual address space (physical size limited only by physical memory)
|
Limited by available kernel-mode virtual address space or the SystemCacheLimit registry key value.
Windows 8.1 and Windows Server 2012 R2: 16 TB.
Windows Vista: Limited only by kernel mode virtual address space. Starting with Windows Vista with SP1, system cache virtual address space can also be limited by the SystemCacheLimit registry key value.
Windows Home Server, Windows Server 2003, and Windows XP: 860 MB with LargeSystemCache registry key set and without 4GT; up to 448 MB with 4GT.
|
Always 1 TB regardless of physical RAM
Windows 8.1 and Windows Server 2012 R2: 16 TB.
Windows Server 2003 and Windows XP: Up to 1 TB depending on configuration and RAM.
|
Physical Memory Limits: Windows 8
The following table specifies the limits on physical memory for Windows 8.
| Version | Limit on X86 | Limit on X64 |
|---|---|---|
| Windows 8 Enterprise |
4 GB
|
512 GB
|
| Windows 8 Professional |
4 GB
|
512 GB
|
| Windows 8 |
4 GB
|
128 GB
|
Physical Memory Limits: Windows Server 2012
The following table specifies the limits on physical memory for Windows Server 2012. Windows Server 2012 is available only in X64 editions.
| Version | Limit on X64 |
|---|---|
| Windows Server 2012 Datacenter |
4 TB
|
| Windows Server 2012 Standard |
4 TB
|
| Windows Server 2012 Essentials |
64 GB
|
| Windows Server 2012 Foundation |
32 GB
|
| Windows Storage Server 2012 Workgroup |
32 GB
|
| Windows Storage Server 2012 Standard |
4 TB
|
| Hyper-V Server 2012 |
4 TB
|
Physical Memory Limits: Windows 7
The following table specifies the limits on physical memory for Windows 7.
| Version | Limit on X86 | Limit on X64 |
|---|---|---|
| Windows 7 Ultimate |
4 GB
|
192 GB
|
| Windows 7 Enterprise |
4 GB
|
192 GB
|
| Windows 7 Professional |
4 GB
|
192 GB
|
| Windows 7 Home Premium |
4 GB
|
16 GB
|
| Windows 7 Home Basic |
4 GB
|
8 GB
|
| Windows 7 Starter |
2 GB
|
N/A
|
Physical Memory Limits: Windows Server 2008 R2
The following table specifies the limits on physical memory for Windows Server 2008 R2. Windows Server 2008 R2 is available only in 64-bit editions.
| Version | Limit on X64 | Limit on IA64 |
|---|---|---|
| Windows Server 2008 R2 Datacenter |
2 TB
| |
| Windows Server 2008 R2 Enterprise |
2 TB
| |
| Windows Server 2008 R2 for Itanium-Based Systems |
2 TB
| |
| Windows Server 2008 R2 Foundation |
8 GB
| |
| Windows Server 2008 R2 Standard |
32 GB
| |
| Windows HPC Server 2008 R2 |
128 GB
| |
| Windows Web Server 2008 R2 |
32 GB
|
Physical Memory Limits: Windows Server 2008
The following table specifies the limits on physical memory for Windows Server 2008. Limits greater than 4 GB for 32-bit Windows assume that PAE is enabled.
| Version | Limit on X86 | Limit on X64 | Limit on IA64 |
|---|---|---|---|
| Windows Server 2008 Datacenter |
64 GB
|
1 TB
| |
| Windows Server 2008 Enterprise |
64 GB
|
1 TB
| |
| Windows Server 2008 HPC Edition |
128 GB
| ||
| Windows Server 2008 Standard |
4 GB
|
32 GB
| |
| Windows Server 2008 for Itanium-Based Systems |
2 TB
| ||
| Windows Small Business Server 2008 |
4 GB
|
32 GB
| |
| Windows Web Server 2008 |
4 GB
|
32 GB
|
Physical Memory Limits: Windows Vista
The following table specifies the limits on physical memory for Windows Vista.
| Version | Limit on X86 | Limit on X64 |
|---|---|---|
| Windows Vista Ultimate |
4 GB
|
128 GB
|
| Windows Vista Enterprise |
4 GB
|
128 GB
|
| Windows Vista Business |
4 GB
|
128 GB
|
| Windows Vista Home Premium |
4 GB
|
16 GB
|
| Windows Vista Home Basic |
4 GB
|
8 GB
|
| Windows Vista Starter |
1 GB
|
Physical Memory Limits: Windows Home Server
Windows Home Server is available only in a 32-bit edition. The physical memory limit is 4 GB.
Physical Memory Limits: Windows Server 2003 R2
The following table specifies the limits on physical memory for Windows Server 2003 R2. Limits over 4 GB for 32-bit Windows assume that PAE is enabled.
| Version | Limit on X86 | Limit on X64 |
|---|---|---|
Windows Server 2003 R2 Datacenter Edition
|
64 GB
(16 GB with 4GT)
|
1 TB
|
Windows Server 2003 R2 Enterprise Edition
|
64 GB
(16 GB with 4GT)
|
1 TB
|
Windows Server 2003 R2 Standard Edition
|
4 GB
|
32 GB
|
Physical Memory Limits: Windows Server 2003 with Service Pack 2 (SP2)
The following table specifies the limits on physical memory for Windows Server 2003 with Service Pack 2 (SP2). Limits over 4 GB for 32-bit Windows assume that PAE is enabled.
| Version | Limit on X86 | Limit on X64 | Limit on IA64 |
|---|---|---|---|
Windows Server 2003 with Service Pack 2 (SP2), Datacenter Edition
|
64 GB
(16 GB with 4GT)
|
1 TB
|
2 TB
|
Windows Server 2003 with Service Pack 2 (SP2), Enterprise Edition
|
64 GB
(16 GB with 4GT)
|
1 TB
|
2 TB
|
Windows Server 2003 with Service Pack 2 (SP2), Standard Edition
|
4 GB
|
32 GB
|
Physical Memory Limits: Windows Server 2003 with Service Pack 1 (SP1)
The following table specifies the limits on physical memory for Windows Server 2003 with Service Pack 1 (SP1). Limits over 4 GB for 32-bit Windows assume that PAE is enabled.
| Version | Limit on X86 | Limit on X64 | Limit on IA64 |
|---|---|---|---|
Windows Server 2003 with Service Pack 1 (SP1), Datacenter Edition
|
64 GB
(16 GB with 4GT)
|
X64 1 TB
|
1 TB
|
Windows Server 2003 with Service Pack 1 (SP1), Enterprise Edition
|
64 GB
(16 GB with 4GT)
|
X64 1 TB
|
1 TB
|
Windows Server 2003 with Service Pack 1 (SP1), Standard Edition
|
4 GB
|
32 GB
|
Physical Memory Limits: Windows Server 2003
The following table specifies the limits on physical memory for Windows Server 2003. Limits over 4 GB for 32-bit Windows assume that PAE is enabled.
| Version | Limit on X86 | Limit on IA64 |
|---|---|---|
Windows Server 2003, Datacenter Edition
|
64 GB
(16 GB with 4GT)
|
512 GB
|
Windows Server 2003, Enterprise Edition
|
64 GB
(16 GB with 4GT)
|
512 GB
|
Windows Server 2003, Standard Edition
|
4 GB
| |
Windows Server 2003, Web Edition
|
2 GB
| |
Windows Small Business Server 2003
|
4 GB
| |
Windows Compute Cluster Server 2003
|
32 GB
| |
Windows Storage Server 2003, Enterprise Edition
|
8 GB
| |
Windows Storage Server 2003
|
4 GB
|
Physical Memory Limits: Windows XP
The following table specifies the limits on physical memory for Windows XP.
| Version | Limit on X86 | Limit on X64 | Limit on IA64 |
|---|---|---|---|
| Windows XP |
4 GB
|
128 GB
|
128 GB (not supported)
|
| Windows XP Starter Edition |
512 MB
|
N/A
|
N/A
|
Physical Memory Limits: Windows Embedded
The following table specifies the limits on physical memory for Windows Embedded.
| Version | Limit on X86 | Limit on X64 |
|---|---|---|
Windows XP Embedded
|
4 GB
| |
Windows Embedded Standard 2009
|
4 GB
| |
Windows Embedded Standard 7
|
4 GB
|
192 GB
|
High Loading time:Load time is normally the initial time it takes an application to start. This should generally be kept to a minimum. While some applications are impossible to make load in under a minute, Load time should be kept under a few seconds if possible.
Speed is the important attributes of an application. A slow running application will lose potential users. Performance testing is done to make sure an app runs fast enough to keep a user’s attention and interest.
High Response time:Response time is the time it takes from when a user inputs data into the application until the application outputs a response to that input. Generally this should be very quick. Again if a user has to wait too long, the user may not wait that much time.he can give up with the high response time.
Poor scalability :A software product suffers from poor scalability when it cannot handle the expected number of users or when it does not accommodate a wide enough range of users. Load testing should be done to be certain the application can handle the anticipated number of users.