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<DIV><FONT face=Arial size=2>----- Original Message ----- <BR>>From: "Leonid
Keller"<BR>>> You can use the __rdtsc ...<BR>>We gave up this
way.<BR>> __rdtsc is complained on the Web to be unstable function,
especially in<BR>>multi-processor environment.<BR><BR>I am coding a test
application right now, and faced the same problem.</FONT></DIV>
<DIV><FONT face=Arial size=2>I haven't found a real solution, and I'm interested
in how you will solve this.</FONT></DIV>
<DIV><FONT face=Arial size=2>These are the informations I
found:<BR></DIV></FONT>
<DIV><FONT face=Arial size=2><A
href="http://www.virtualdub.org/blog/pivot/entry.php?id=106">http://www.virtualdub.org/blog/pivot/entry.php?id=106</A><BR><A
href="http://blogs.msdn.com/oldnewthing/archive/2008/09/08/8931563.aspx">http://blogs.msdn.com/oldnewthing/archive/2008/09/08/8931563.aspx</A><BR><A
href="http://support.microsoft.com/kb/172338/en-us">http://support.microsoft.com/kb/172338/en-us</A><BR><A
href="http://support.microsoft.com/kb/938448/en-us">http://support.microsoft.com/kb/938448/en-us</A><BR><A
href="http://support.microsoft.com/kb/274323/en-us">http://support.microsoft.com/kb/274323/en-us</A><BR></FONT></DIV>
<DIV><FONT face=Arial size=2>I'm still using QueryPerformanceCounter right
now, but I don't really know how much trust to put in
it.<BR></FONT><FONT face=Arial size=2><BR>>If it is that simple why didn't
Microsoft use it in<BR>>QueryPerformanceCounter implementation ?
:(<BR>><BR>>Let's formulate our problem:<BR>>We have to measure a very
fast process and the time T of the<BR>>time stamping itself influence the
results.<BR>><BR>>Possible solutions:<BR>>1. Exclude T from the result
by some artificial trick. (as in the<BR>>discussed patch)<BR>>2. Measure T
before the loop and subtract after.<BR>>3. Make stampings once in N loops
decreasing N times it's influence.<BR>>4. ?<BR>><BR>>What would you
prefere ?<BR>></FONT></DIV></BODY></HTML>