On Wed, May 28, 2014 at 05:41:08PM +0200, Marco van de Voort wrote: > In our previous episode, Henry Vermaak said: > > On linux, The TSC gets calibrated and the synchronisation is tested, which > > may result in the TSC clock source being marked as unstable and disabled. > > In this case, it will fall back to using other clock sources (HPET is next > > in line on my computer). > > I assume the same system underlies queryperformancecounter and family on > Windows. But that means you need to use OS timing functions, and not ASM.
I assumed that, too. All the clocksource calibration and selection happens at startup, so by the time you call clock_gettime()/QueryPerformanceCounter() it knows whether to query the TSC/HPET/whatever. Blindly making assumptions about TSC stability can get you into trouble. Microsoft advises against this, too: http://msdn.microsoft.com/en-gb/library/windows/desktop/ee417693%28v=vs.85%29.aspx Henry _______________________________________________ fpc-pascal maillist - fpc-pascal@lists.freepascal.org http://lists.freepascal.org/cgi-bin/mailman/listinfo/fpc-pascal
