Subject: Re: Using splsched()
To: Eduardo E. Horvath <>
From: Jonathan Stone <jonathan@DSG.Stanford.EDU>
List: tech-kern
Date: 11/13/1997 16:14:33
>Has there been any consideration of sampling some sort of high resolution
>timer at trap/context switch time instead of using a high resolution timer
>interrupt for statistics gathering?  It could elimitate the splstatclock()
>problems at the same time as improving overall timing accuracy.

1) Not all systems have such a timer.    (sparcs do, but...)

2) that might work for process accouting and maybe user PC-sampling
   (tho there are applications that synch to the sheduling clock, where
   where you really want a different clock, if possible).

   But  I don't understand how you would get *kernel* profiling
   data via this technique.  Without that, how would we tune kernels?
   (some ports do tune the MD kernel code).