Milena Petrovic

Windows Performance Monitor basics

March 12, 2014 by
Windows Performance Monitor is a tool shipped with Windows that can be used to monitor and examine how applications affect computer performance. It can measure real-time server performance and save the measured values into a log file that can be analyzed later. It enables real time system and SQL Server performance monitoring, tracking the performance impact of applications and services, setting threshold for each monitored metric, and generating an alert or performing a specific action when the defined threshold is exceeded

Windows Server 2003 had a utility named System Monitor. Later versions – Windows 7, Windows 8, Windows Server 2008 R2, and Windows Server 2012 have Performance Monitor as a part of Performance Monitor, or Reliability and Performance Monitor parent snap-in. Earlier Windows versions had Performance Monitor Wizard – a utility that was not shipped with Windows, so it had to be downloaded and installed additionally

The Windows Performance Monitor parent snap-in consists of three elements – Monitoring Tools (this is where Performance Monitor is), Data Collector Sets, and Reports. The focus of this article is on Monitoring Tools Performance Monitor, also known as Performance Monitor or PerfMon

Monitoring Tools Performance Monitor (PerfMon)

Performance Monitor provides a wide range of measures that can be monitored. Monitoring the right set of available counters narrows down the problem origin to a specific component or application and enables efficient and quick problem troubleshooting. Some of the performance counters don’t provide enough information when monitored alone. When their values are above the recommended threshold, they don’t clearly indicate performance problems. To be able to determine whether there is a performance problem, other counters should be monitored and their values compared

For example, the Page faults/sec counter shows both hard and soft page faults. Soft page faults don’t affect SQL Server performance, but hard page faults do. That’s why high Page faults/sec values don’t necessarily indicate performance problems. To determine whether that is the case, monitoring another counter that also indicates hard page faults – the Page reads/sec value is recommended. If it is also high, there is most likely a performance problem. To be sure, monitor disk behavior and paging via memory and disk counters, such as Pages Output/sec, Pages Input/sec, Disk Reads/sec, and Avg. Disk Read Bytes/sec

Without monitoring all necessary counters, the information obtained can be insufficient or misleading for determining the system state and making correct decisions

When it comes to selecting the counters, it’s necessary to understand what they represent, what are acceptable values, is there an exact threshold, or is the value determined based on a trend line

Performance Monitor provides graphical presentation of the metrics collected by Data Collector Sets and Event Trace Sessions, both in real time and as historical data

Besides the Windows performance parameters, Performance Monitor provides a range of parameters useful for SQL Server performance monitoring. On a machine where SQL Server is installed, SQL Server related counters are automatically added to Performance Monitor

How Performance Monitor works

Performance Monitor presents built-in Windows and application performance counters in easy-to read graphs. It can show live, real time data as well as data stored in *.blg, *.csv, or *.tsv log files. The latter feature makes is useful for performance analysis and determining performance trends. All data can be presented as line graphs, histogram bars, or reports

The performance counters presented in Performance Monitor can be defined via custom Data Collector Sets

Data Collector Sets contain performance counters, event trace data, and system configuration information. Performance counters measure system state and activity. Performance Monitor periodically requests the current value of performance counters and represents them graphically, or in the reports. Event trace data is gathered from trace files created by the system or application. Configuration information is obtained from the Windows registry

To be able to set monitored metrics and use all Performance Monitor features, a user has to be a member of the local Administrators group. A member of the Users group can only open saved log files in Performance Monitor and set the graph properties. Real time monitoring is not possible for these users

There are two more user groups specific for this utility: Performance Monitor Users and Performance Log Users. The first one allows viewing real time and saved log files in Performance Monitor and setting the graph properties for both. Creating and modifying Data Collector Sets is not allowed. In addition to the features available for the Performance Monitor Users group users, the Performance Log Users group allows creating and modifying Data Collector Sets, except the NT Kernel trace

What information can Performance Monitor gather?

The counters that can be monitored in Performance Monitor are grouped for easier referencing. The available groups depend on the operating system and applications installed on the monitored machine. Available groups are: Memory, Network Interface, Physical Disk, Process, Processor, Server, System, and many more

When it comes to SQL Server, counter groups are named MSSQL$SQL<version>:<counter_name>. For SQL Server 2012, there are more than 30 groups. For example, the MSSQL$SQL2012:Databases counter group contains more than 600 counters that monitor data and log file size, growth, truncation, shrinks, percentage and KB of log file used, various metrics about transactions, log cache, log flush, and many more. The MSSQL$SQL2012:Locks group contains more than 100 counters that monitor lock requests, timeouts, wait time, and more on various resources – database files, index rows, catalog information, table, view, stored procedure or other database object, etc.

While the MSSQL$SQL counters enable detailed and in-depth analysis of the SQL Server performance, the most commonly monitored counters for troubleshooting SQL Server performance issues belong to the Memory, Processor, Physical Disk, and Network Interface groups

Each of these groups contains multiple counters. For example, the Memory group contains more than 30 counters among which the most important are Available Bytes, Page Faults/sec, Page reads/sec, Page Writes/sec, Pages Input/sec, Pages Output/sec, and Pages/sec

Available counters and their instances

Multiple instances are shown for a counter if there are multiple processors on the machine and if tracking the counter per processor makes sense, such as for Processor and Processor Information counters. You can monitor each processor individually, or all instances

Monitoring each processor individually, or all instances

Although active monitoring makes little overhead, to avoid monitoring the overhead along with the system and application performance, use Performance Monitor to monitor a remote machine

In SQL Server performance tuning using Performance Monitor, we give detailed steps for using Windows Performance Monitor

Milena Petrovic