Re: Getting Peak Commit from NtQuerySystemInformation

Hi Thomas,

On 3/3/2010 3:14 AM, Thomas Heller wrote:
> Mike Driscoll schrieb:
>    
>> Hi,
>>
>> I was tasked with finding a way to query our workstations for their Peak
>> Commit Charge. According to the sysinternals forum:
>>
>> "The only way I'm aware of that one can get this detail is from the
>> uMmPeakCommitLimit member of the SYSTEM_PERFORMANCE_INFORMATION
>> structure one passes to NtQuerySystemInformation when calling it with
>> the SystemPerformanceInformation type." (see
>> http://forum.sysinternals.com/forum_posts.asp?TID=15540&PID=75852)
>>
>> I started with this question on the PyWin32 mailing list, but it turns
>> out that they don't expose the functionality inside
>> NtQuerySystemInformation so that's why I came here. Unfortunately, I'm a
>> complete newb when it comes to ctypes. While I did find that this worked
>> "ctypes.windll.ntdll.NtQuerySystemInformation", I don't know how to go
>> on and actually query the object. Can someone give me a clue?
>>
>> I'm running Python 2.5 on Windows XP. Thanks!
>>      
> Not really tested, but seems to work:
>
> <snip>
> from ctypes import *
>
> SystemBasicInformation = 0
> SystemPerformanceInformation = 2
>
> class SYSTEM_BASIC_INFORMATION(Structure):
>      _fields_ = [("Reserved1", c_long * 10),
>                  ("NumberOfProcessors", c_byte),
>                  ("bUnknown2", c_byte),
>                  ("bUnknown3", c_short)
>                  ]
>
> class SYSTEM_PERFORMANCE_INFORMATION(Structure):
>      _fields_ = [("IdleTime", c_int64),
>                  ("ReadTransferCount", c_int64),
>                  ("WriteTransferCount", c_int64),
>                  ("OtherTransferCount", c_int64),
>                  ("ReadOperationCount", c_ulong),
>                  ("WriteOperationCount", c_ulong),
>                  ("OtherOperationCount", c_ulong),
>                  ("AvailablePages", c_ulong),
>                  ("TotalCommittedPages", c_ulong),
>                  ("TotalCommitLimit", c_ulong),
>                  ("PeakCommitment", c_ulong),
>                  ("PageFaults", c_ulong),
>                  ("WriteCopyFaults", c_ulong),
>                  ("TransitionFaults", c_ulong),
>                  ("Reserved1", c_ulong),
>                  ("DemandZeroFaults", c_ulong),
>                  ("PagesRead", c_ulong),
>                  ("PageReadIos", c_ulong),
>                  ("Reserved2", c_ulong * 2),
>                  ("PagefilePagesWritten", c_ulong),
>                  ("PagefilePageWriteIos", c_ulong),
>                  ("MappedFilePagesWritten", c_ulong),
>                  ("MappedFilePageWriteIos", c_ulong),
>                  ("PagedPoolUsage", c_ulong),
>                  ("NonPagedPoolUsage", c_ulong),
>                  ("PagedPoolAllocs", c_ulong),
>                  ("PagedPoolFrees", c_ulong),
>                  ("NonPagedPoolAllocs", c_ulong),
>                  ("NonPagedPoolFrees", c_ulong),
>                  ("TotalFreeSystemPtes", c_ulong),
>                  ("SystemCodePage", c_ulong),
>                  ("TotalSystemDriverPages", c_ulong),
>                  ("TotalSystemCodePages", c_ulong),
>                  ("SmallNonPagedLookasideListAllocateHits", c_ulong),
>                  ("SmallPagedLookasideListAllocateHits", c_ulong),
>                  ("Reserved3", c_ulong),
>                  ("MmSystemCachePage", c_ulong),
>                  ("PagedPoolPage", c_ulong),
>                  ("SystemDriverPage", c_ulong),
>                  ("FastReadNoWait", c_ulong),
>                  ("FastReadWait", c_ulong),
>                  ("FastReadResourceMiss", c_ulong),
>                  ("FastReadNotPossible", c_ulong),
>                  ("FastMdlReadNoWait", c_ulong),
>                  ("FastMdlReadWait", c_ulong),
>                  ("FastMdlReadResourceMiss", c_ulong),
>                  ("FastMdlReadNotPossible", c_ulong),
>                  ("MapDataNoWait", c_ulong),
>                  ("MapDataWait", c_ulong),
>                  ("MapDataNoWaitMiss", c_ulong),
>                  ("MapDataWaitMiss", c_ulong),
>                  ("PinMappedDataCount", c_ulong),
>                  ("PinReadNoWait", c_ulong),
>                  ("PinReadWait", c_ulong),
>                  ("PinReadNoWaitMiss", c_ulong),
>                  ("PinReadWaitMiss", c_ulong),
>                  ("CopyReadNoWait", c_ulong),
>                  ("CopyReadWait", c_ulong),
>                  ("CopyReadNoWaitMiss", c_ulong),
>                  ("CopyReadWaitMiss", c_ulong),
>                  ("MdlReadNoWait", c_ulong),
>                  ("MdlReadWait", c_ulong),
>                  ("MdlReadNoWaitMiss", c_ulong),
>                  ("MdlReadWaitMiss", c_ulong),
>                  ("ReadAheadIos", c_ulong),
>                  ("LazyWriteIos", c_ulong),
>                  ("LazyWritePages", c_ulong),
>                  ("DataFlushes", c_ulong),
>                  ("DataPages", c_ulong),
>                  ("ContextSwitches", c_ulong),
>                  ("FirstLevelTbFills", c_ulong),
>                  ("SecondLevelTbFills", c_ulong),
>                  ("SystemCalls", c_ulong)]
>
> sbi = SYSTEM_BASIC_INFORMATION()
> retlen = c_ulong()
>
> res = windll.ntdll.NtQuerySystemInformation(SystemBasicInformation,
>                                              byref(sbi),
>                                              sizeof(sbi),
>                                              byref(retlen))
> print res, retlen
> print sbi.NumberOfProcessors
>
>
> spi = SYSTEM_PERFORMANCE_INFORMATION()
> retlen = c_ulong()
>
> res = windll.ntdll.NtQuerySystemInformation(SystemPerformanceInformation,
>                                              byref(spi),
>                                              sizeof(spi),
>                                              byref(retlen))
> print res, retlen
> print spi.PeakCommitment
>
> </snip>
>
>    

When I run this on my machine, it gives me 368456 as the result, whereas 
Task Manager give me 1473824. Stupid question, but do I need to convert 
the long to a kilobyte or something?  I tried, but that was way off, so 
I must be doing something wrong. Thank you for your help!

- Mike

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