Performance Counters for ASP.NET

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ASP.NET supports two groups of performance counters: system and application. The former are exposed in PerfMon in the ASP.NET System performance counter object; the latter are exposed in the ASP.NET Applications performance object.

Note

There's a significant difference between the State Server Sessions counters found in the ASP.NET System performance object and the Sessions counters found in the ASP.NET Applications performance object. The former apply only on the server computer on which the state server is running. The latter apply only to user sessions that occur in process.

Table C-11 lists the ASP.NET system performance counters. These aggregate information for all ASP.NET applications on a Web server computer, or they apply generally to a system of ASP.NET servers running the same applications. These can include Web farms and Web gardens.

Table C-11. ASP.NET System Performance Counters

Counter	Description
Application Restarts	The number of times that an application has been restarted during the Web server's lifetime. Application restarts are incremented with each Application_OnEnd event. This value will be reset every time the Internet Information Services (IIS) host is restarted.
Application Running	The number of applications running on the server computer.
Requests Disconnected	The number of requests disconnected due to a communication failure.
Requests Queued	The number of requests waiting for service from the queue.
Requests Rejected	The total number of requests not executed because of insufficient server resources to process them. This counter represents the number of requests that return a 503 HTTP status code, indicating that the server is too busy.
Request Wait Time	The number of milliseconds that the most recent request waited for processing in the queue.
State Server Sessions Abandoned	The number of user sessions that have been explicitly abandoned. These are sessions that are ended by specific user actions, such as closing the browser or navigating to another site. This counter is available only on the computer where the state server service ( aspnet_state ) is running.
State Server Sessions Active	The number of currently active user sessions. This counter is available only on the computer where the state server service ( aspnet_state ) is running.
State Server Sessions Timed Out	The number of user sessions that have become inactive through user inaction. This counter is available only on the machine where the state server service ( aspnet_state ) is running.
State Server Sessions Total	The number of sessions created during the lifetime of the process. This counter is the cumulative value of State Server Sessions Active , State Server Sessions Abandoned , and State Server Sessions Timed Out . This counter is available only on the computer where the state server service ( aspnet_state ) is running.
Worker Process Restarts	The number of times a worker process has been restarted on the server computer.
Worker Process Running	The number of worker processes running on the server computer.

ASP.NET Applications

ASP.NET supports the application performance counters listed in Table C-12, which you can use to monitor the performance of a single instance of an ASP.NET application. A unique instance appears for these counters, named __Total__ , which aggregates counters for all applications on a Web server (similar to the global counters above). The __Total__ instance is always available. The counters will display zero when no applications are present on the server.

Table C-12. ASP.NET Performance Counters

Counter	Description
Anonymous Requests	The cumulative number of requests using anonymous authentication. This number is reset when IIS is restarted (either through an IIS reset or a rebooting of the machine).
Anonymous Requests/Sec	The number of requests per second using anonymous authentication.
Cache Total Entries	The total number of entries in the cache. This counter includes both internal use of the cache by the ASP.NET page framework and external use of the cache through exposed APIs.
Cache Total Hits	The total number of hits from the cache. This counter includes both internal use of the cache by the ASP.NET page framework and external use of the cache through exposed APIs.
Cache Total Misses	The number of failed cache requests per application. This counter includes both internal use of the cache by ASP.NET and external use of the cache through exposed APIs.
Cache Total Hit Ratio	The ratio of hits to misses for the cache. This counter includes both internal use of the cache by ASP.NET and external use of the cache through exposed APIs.
Cache Total Turnover Rate	The number of additions and removals to the total cache per second. It is useful in helping determine how effectively the cache is being used. If the turnover is large, then the cache is not being used efficiently .
Cache API Entries	The total number of entries in the application cache.
Cache API Hits	The total number of hits from the cache when it is accessed through only the external cache APIs. This counter does not track any use of the cache internally by ASP.NET.
Cache API Misses	The total number of failed requests to the cache when accessed through the external cache APIs. This counter does not track any use of the cache internally by ASP.NET.
Cache API Hit Ratio	The cache hit to miss ratio when accessed through the external Cache APIs. This counter does not track any use of the cache internally by ASP.NET.
Cache API Turnover Rate	The number of additions and removals to the cache per second, when used through the external APIs (excluding internal use by the ASP.NET page framework). It is useful in helping determine how effectively the cache is being used. If the turnover is large, then the cache is not being used effectively.
Compilations Total	The total number of compilations that have taken place during the lifetime of the current Web server process. This occurs when a file with an .aspx, .asmx, .ascx, or .ashx extension, or a code-behind source file, is dynamically compiled on the server. Note that this number will initially climb to a peak value as requests are made to all parts of an application. Once a compilation occurs, however, the resulting binary is saved to disk, where it is reused until its source file changes. This means that, even in the event of a process restart, the counter can remain at zero (inactive) until the application is modified or redeployed.
Debugging Requests	The number of requests that occur while debugging was enabled.
Errors During Preprocessing	The number of errors that occurred during parsing. Excludes compilation and run time errors.
Errors During Compilation	The number of errors that occur during dynamic compilation. Excludes parser and run time errors.
Errors During Execution	The total number of errors that occur during the execution of an HTTP request. Excludes parser and compilation errors.
Errors Unhandled During ­Execution	The total number of unhandled errors that occur during the execution of HTTP requests. Note that an unhandled error is any uncaught run ­time exception that escapes user code on the page and enters the ASP.NET internal error-handling logic. Exceptions to this rule occur when: Custom errors are enabled, an error page is defined, or both. The Page_Error event is defined in user code and the error is either cleared (using the HttpServerUtility.ClearError Method method) or a redirect is performed.
Errors Unhandled During ­Execution/Sec	The number of unhandled exceptions per second that occur during the execution of HTTP requests.
Errors Total	The total number of errors that occur during the execution of HTTP requests. Includes any parser, compilation, or run time errors. This counter is the sum of the Errors During Compilation , Preprocessing , and Request Execution counters.
Errors Total/Sec	The number of errors per second that occur during the execution of HTTP requests. Includes any parser, compilation, or run time error.
Output Cache Entries	The total number of entries in the output cache.
Output Cache Hits	The total number of requests serviced from the output cache.
Output Cache Misses	The number of failed output-cache requests per application.
Output Cache Hit Ratio	The percentage of total requests serviced from the output cache.
Output Cache Turnover Rate	The number of additions and removals to the output cache per second. This is useful in helping determine how effectively the cache is being used. If the turnover is large, then the cache is not being used effectively.
Pipeline Instance Count	The number of active pipeline instances.
Request Bytes In Total	The total size , in bytes, of all requests.
Request Bytes Out Total	The total size, in bytes, of responses sent to a client. This does not include standard HTTP response headers.
Requests Executing	The number of requests currently executing.
Requests Failed	The total number of failed requests, including requests that timed out, requests that were not authorized (401), or requests not found (404 or 414). Note: the equivalent ASP counter would also increment on requests rejected, which cannot be done (because the rejection is done by IIS and not the process model).
Requests Not Found	The number of requests that failed because resources were not found (status code 404, 414).
Requests Not Authorized	The number of requests that failed due to no authorization (status code 401).
Requests Succeeded	The number of requests that executed successfully (status code 200).
Requests Timed Out	The number of requests that timed out.
Requests Total	The total number of requests since the service was started.
Requests/Sec	The number of requests executed per second.
Sessions Active	The number of sessions currently active. This is supported only with in-memory session state.
Sessions Abandoned	The number of sessions that have been explicitly abandoned. This is supported only with in-memory session state.
Sessions Timed Out	The number of sessions that timed out. This is supported only with in-memory session state.
Sessions Total	The number of sessions timed out. This is supported only with in-memory session state.
Transactions Aborted	The number of transactions aborted.
Transactions Committed	The number of transactions committed.
Transactions Pending	The number of transactions in progress.
Transactions Total	The total number of transactions since the service was started.
Transactions/Sec	The number of transactions started per second.

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