Monitoring CPU Usage in C#

Encoding EAN13 in C# Monitoring CPU Usage

A quick and easy way to see how much CPU is being utilized in the system is via the Windows Task Manager. Task Manager provides a graphical view of the percentage of CPU being used by all the processors in the system. The CPU and memory performance views are selected by clicking on the Performance tab in Windows Task Manager. The CPU and memory view of Task Manager is shown in Figure 6-3. Note

CPU and memory are somewhat unique in that they both have a finite value. Both CPU and memory can reach 100 percent utilization. When CPU reaches 100 percent utilization, tasks queue up waiting for the CPU to become

available. When memory reaches 100 percent utilization, other memory is paged out. However, both cause performance problems.

In Figure 6-3, you can see the CPU utilization in the top left box with the CPU history (for each CPU, core, or hyperthread CPU) to the right. Below that is the Page File utilization with its history to the right. Underneath are additional data for the following:

Physical Memory This is the actual RAM in the system and includes total, how much is available and how much is used for system cache. Commit Charge How much memory has been allocated to the operating system and to programs. This includes the total, peak, and how much the memory is limited (RAM plus paging file). Kernel Memory The memory used by the operating system kernel is shown as a total and how much is paged and nonpaged memory.

Figure 6-3

In addition, CPU utilization can be measured from the processor performance object within perfmon. Perfmon is the Windows Performance Monitor and is invoked from the Start menu by selecting Administrative Tools, then Performance. Perfmon is made up of objects, such as Processor, Processes, Physical Disk, etc., and counters such as the ones listed here. The actual CPU utilization is measured via the following counters:

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Percent processor time The total percentage of time that the CPU is active based on the total capacity of the CPU Percent user time The total CPU utilization for user programs; represents work done on behalf of user programs Percent privileged time The CPU utilization for the Windows operating system; includes the operating system functions as well as device drivers (except for interrupt processing) Percent interrupt time The percentage of CPU time spent servicing interrupts Percent idle time The percentage of time that the CPU isn t doing anything Note

When selecting counters, you can always click the Explain button. This will provide a description of what that counter information is providing.

Windows CPU counters are shown in Figure 6-4.

Figure 6-4

Perfmon is a powerful and useful tool that can be used to help with system and SQL Server tuning, sizing, and capacity planning. In addition, you can get a limited amount of CPU information from SQL Server itself. The @@CPU_BUSY function within SQL Server provides information on how much CPU time SQL Server itself has used. This is a cumulative counter in ticks. Multiply by @@timeticks to get the number of milliseconds. By setting up timers and finding the number of milliseconds of CPU time and the elapsed time you can get a good indication of how much CPU percentage is being used. To get the milliseconds of CPU time used, use this syntax:

SELECT @@CPU_BUSY * @@timeticks;

You can use @@CPU_BUSY, @@IO_BUSY in order to save SQL Server performance data to a table in a database. In this way, you can save long term performance data.

Perfmon data can be saved directly into a SQL Server database. This information can be extremely valuable since it can be saved for a long period of time. While a day s worth of CPU data from perfmon might be mildly useful for future planning, a year s worth is very useful, as shown in Figure 6-5.

90 80 70 60 % CPU Utilization 50 40 30 20 10 0 10/16/2000 10/23/2000 10/30/2000 11/13/2000 11/20/2000 11/27/2000 12/11/2000 12/18/2000 7/10/2000 7/17/2000 7/24/2000 7/31/2000 8/14/2000 8/21/2000 8/28/2000 9/11/2000 9/18/2000 9/25/2000 10/2/2000 10/9/2000 11/6/2000 12/4/2000 7/3/2000 8/7/2000 9/4/2000