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Rework realtime priority support:

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- Move the realtime priority range up above kernel sleep priorities and
  just below interrupt thread priorities.
- Contract the interrupt and kernel sleep priority ranges a bit so that
  the timesharing priority band can be increased.  The new timeshare range
  is now slightly larger than the old realtime + timeshare ranges.
- Change the ULE scheduler to no longer use realtime priorities for
  interactive threads.  Instead, the larger timeshare range is now split
  into separate subranges for interactive and non-interactive ("batch")
  threads.  The end result is that interactive threads and non-interactive
  threads still use the same priority ranges as before, but realtime
  threads now have a separate, dedicated priority range.
- Do not modify the priority of non-timeshare threads in sched_sleep()
  or via cv_broadcastpri().  Realtime and idle priority threads will
  no longer have their priorities affected by sleeping in the kernel.

Reviewed by:	jeff
This commit is contained in:
John Baldwin 2011-01-14 17:06:54 +00:00
parent 640c77e126
commit 2dc29adb9f
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=217410
4 changed files with 26 additions and 17 deletions
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2
sys/kern/sched_4bsd.c
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@ -908,7 +908,7 @@ sched_sleep(struct thread *td, int pri)
THREAD_LOCK_ASSERT(td, MA_OWNED);
td->td_slptick = ticks;
td->td_sched->ts_slptime = 0;
if (pri)
if (pri != 0 && PRI_BASE(td->td_pri_class) == PRI_TIMESHARE)
sched_prio(td, pri);
if (TD_IS_SUSPENDED(td) || pri >= PSOCK)
td->td_flags |= TDF_CANSWAP;

16
sys/kern/sched_ule.c
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@ -118,11 +118,17 @@ static struct td_sched td_sched0;
/*
* Priority ranges used for interactive and non-interactive timeshare
* threads. Interactive threads use realtime priorities.
* threads. The timeshare priorities are split up into four ranges.
* The first range handles interactive threads. The last three ranges
* (NHALF, x, and NHALF) handle non-interactive threads with the outer
* ranges supporting nice values.
*/
#define PRI_MIN_INTERACT PRI_MIN_REALTIME
#define PRI_MAX_INTERACT PRI_MAX_REALTIME
#define PRI_MIN_BATCH PRI_MIN_TIMESHARE
#define PRI_TIMESHARE_RANGE (PRI_MAX_TIMESHARE - PRI_MIN_TIMESHARE + 1)
#define PRI_INTERACT_RANGE ((PRI_TIMESHARE_RANGE - SCHED_PRI_NRESV) / 2)
#define PRI_MIN_INTERACT PRI_MIN_TIMESHARE
#define PRI_MAX_INTERACT (PRI_MIN_TIMESHARE + PRI_INTERACT_RANGE - 1)
#define PRI_MIN_BATCH (PRI_MIN_TIMESHARE + PRI_INTERACT_RANGE)
#define PRI_MAX_BATCH PRI_MAX_TIMESHARE
/*
@ -1893,6 +1899,8 @@ sched_sleep(struct thread *td, int prio)
td->td_slptick = ticks;
if (TD_IS_SUSPENDED(td) || prio >= PSOCK)
td->td_flags |= TDF_CANSWAP;
if (PRI_BASE(td->td_pri_class) != PRI_TIMESHARE)
return;
if (static_boost == 1 && prio)
sched_prio(td, prio);
else if (static_boost && td->td_priority > static_boost)

3
sys/kern/subr_sleepqueue.c
View File

@ -745,7 +745,8 @@ sleepq_resume_thread(struct sleepqueue *sq, struct thread *td, int pri)
/* Adjust priority if requested. */
MPASS(pri == 0 || (pri >= PRI_MIN && pri <= PRI_MAX));
if (pri != 0 && td->td_priority > pri)
if (pri != 0 && td->td_priority > pri &&
PRI_BASE(td->td_pri_class) == PRI_TIMESHARE)
sched_prio(td, pri);
/*

22
sys/sys/priority.h
View File

@ -67,10 +67,10 @@
* Priorities range from 0 to 255, but differences of less then 4 (RQ_PPQ)
* are insignificant. Ranges are as follows:
*
* Interrupt threads: 0 - 63
* Top half kernel threads: 64 - 127
* Realtime user threads: 128 - 159
* Time sharing user threads: 160 - 223
* Interrupt threads: 0 - 47
* Realtime user threads: 48 - 79
* Top half kernel threads: 80 - 119
* Time sharing user threads: 120 - 223
* Idle user threads: 224 - 255
*
* XXX If/When the specific interrupt thread and top half thread ranges
@ -81,7 +81,7 @@
#define PRI_MAX (255) /* Lowest priority. */
#define PRI_MIN_ITHD (PRI_MIN)
#define PRI_MAX_ITHD (PRI_MIN_KERN - 1)
#define PRI_MAX_ITHD (PRI_MIN_REALTIME - 1)
#define PI_REALTIME (PRI_MIN_ITHD + 0)
#define PI_AV (PRI_MIN_ITHD + 4)
@ -92,8 +92,11 @@
#define PI_SOFT (PRI_MIN_ITHD + 24)
#define PI_SWI(x) (PI_SOFT + (x) * RQ_PPQ)
#define PRI_MIN_KERN (64)
#define PRI_MAX_KERN (PRI_MIN_REALTIME - 1)
#define PRI_MIN_REALTIME (48)
#define PRI_MAX_REALTIME (PRI_MIN_KERN - 1)
#define PRI_MIN_KERN (80)
#define PRI_MAX_KERN (PRI_MIN_TIMESHARE - 1)
#define PSWP (PRI_MIN_KERN + 0)
#define PVM (PRI_MIN_KERN + 4)
@ -106,10 +109,7 @@
#define PLOCK (PRI_MIN_KERN + 32)
#define PPAUSE (PRI_MIN_KERN + 36)
#define PRI_MIN_REALTIME (128)
#define PRI_MAX_REALTIME (PRI_MIN_TIMESHARE - 1)
#define PRI_MIN_TIMESHARE (160)
#define PRI_MIN_TIMESHARE (120)
#define PRI_MAX_TIMESHARE (PRI_MIN_IDLE - 1)
#define PUSER (PRI_MIN_TIMESHARE)