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- Shift the tick count by 10 and back around sched_pctcpu_update()

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calculations.  Keep this changes local to the function so the tick count
   is in its natural form otherwise.  Previously 1000 was added each time
   a tick fired and we divided by 1000 when it was reported.  This is done
   to reduce rounding errors.
This commit is contained in:
Jeff Roberson 2003-03-03 05:29:09 +00:00
parent 9f7b7e45d1
commit 65c8760dbf
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=111793
1 changed files with 8 additions and 2 deletions
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10
sys/kern/sched_ule.c
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@ -418,8 +418,14 @@ sched_pctcpu_update(struct kse *ke)
/*
* Adjust counters and watermark for pctcpu calc.
*/
/*
* Shift the tick count out so that the divide doesn't round away
* our results.
*/
ke->ke_ticks <<= 10;
ke->ke_ticks = (ke->ke_ticks / (ke->ke_ltick - ke->ke_ftick)) *
SCHED_CPU_TICKS;
ke->ke_ticks >>= 10;
ke->ke_ltick = ticks;
ke->ke_ftick = ke->ke_ltick - SCHED_CPU_TICKS;
}
@ -665,7 +671,7 @@ sched_clock(struct thread *td)
KASSERT((td != NULL), ("schedclock: null thread pointer"));
/* Adjust ticks for pctcpu */
ke->ke_ticks += 10000;
ke->ke_ticks++;
ke->ke_ltick = ticks;
/* Go up to one second beyond our max and then trim back down */
if (ke->ke_ftick + SCHED_CPU_TICKS + hz < ke->ke_ltick)
@ -865,7 +871,7 @@ sched_pctcpu(struct kse *ke)
sched_pctcpu_update(ke);
/* How many rtick per second ? */
rtick = ke->ke_ticks / (SCHED_CPU_TIME * 10000);
rtick = ke->ke_ticks / SCHED_CPU_TIME;
pctcpu = (FSCALE * ((FSCALE * rtick)/realstathz)) >> FSHIFT;
}