Friday, 2 March 2012

Performance memory counters

Performance memory counters
Page Faults/sec
Shows the average number of pages faulted per second, which is equal to the number of page fault operations because only one page is faulted in each fault operation. This counter includes both hard faults (those that require disk access) and soft faults (where the faulted page is found elsewhere in physical memory). Most processors can handle large numbers of soft faults without significant consequence. However, hard faults can cause delays because they require disk access..
Page Reads/sec
Shows the rate, in incidents per second, at which the disk was read to resolve hard page faults. This counter shows numbers of read operations, without regard to the number of pages retrieved in each operation. Hard page faults occur when a process references a page in virtual memory that must be retrieved from disk because it is not in its working set or elsewhere in physical memory. This counter is a primary indicator for the kinds of faults that cause system-wide delays. It includes read operations to satisfy faults in the file system cache (usually requested by applications) and in noncached mapped memory files. Compare the value of Page Reads/sec to the value of Pages Input/sec to find an average of how many pages were read during each read operation.
Page Writes/sec
Shows the rate, in incidents per second, at which pages were written to disk to free up space in physical memory. Pages are written to disk only if they are changed while in physical memory, so they are likely to hold data, not code. This counter shows write operations, without regard to the number of pages written in each operation.
Pages Input/sec
Shows the rate, in incidents per second, at which pages were read from disk to resolve hard page faults. Hard page faults occur when a process refers to a page in virtual memory that must be retrieved from disk because it is not in its working set or elsewhere in physical memory. When a page is faulted, the system tries to read multiple contiguous pages into memory to maximize the benefit of the read operation. Compare Pages Input/sec to Page Reads/sec to find the average number of pages read into memory during each read operation
Pages Output/sec
Shows the rate, in incidents per second, at which pages were written to disk to free up space in physical memory. A high rate of pages output might indicate a memory shortage. The Windows Server 2003 family writes more pages back to disk to free up space when physical memory is in short supply. This counter shows numbers of pages, and can be compared to other counts of pages without conversion.
Pages/sec
Shows the rate, in incidents per second, at which pages were read from or written to disk to resolve hard page faults. This counter is a primary indicator for the kinds of faults that cause system-wide delays. It is the sum of Pages Input/sec and Pages Output/sec. It is counted in numbers of pages, so it can be directly compared to other counts of pages such as Page Faults/sec. It includes pages retrieved to satisfy faults in the file system cache (usually requested by applications) and noncached mapped memory files.

  



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