svn commit: r217410 - in head/sys: kern sys
John Baldwin
jhb at FreeBSD.org
Fri Jan 14 17:06:54 UTC 2011
Author: jhb
Date: Fri Jan 14 17:06:54 2011
New Revision: 217410
URL: http://svn.freebsd.org/changeset/base/217410
Log:
Rework realtime priority support:
- 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
Modified:
head/sys/kern/sched_4bsd.c
head/sys/kern/sched_ule.c
head/sys/kern/subr_sleepqueue.c
head/sys/sys/priority.h
Modified: head/sys/kern/sched_4bsd.c
==============================================================================
--- head/sys/kern/sched_4bsd.c Fri Jan 14 16:42:13 2011 (r217409)
+++ head/sys/kern/sched_4bsd.c Fri Jan 14 17:06:54 2011 (r217410)
@@ -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;
Modified: head/sys/kern/sched_ule.c
==============================================================================
--- head/sys/kern/sched_ule.c Fri Jan 14 16:42:13 2011 (r217409)
+++ head/sys/kern/sched_ule.c Fri Jan 14 17:06:54 2011 (r217410)
@@ -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.
- */
-#define PRI_MIN_INTERACT PRI_MIN_REALTIME
-#define PRI_MAX_INTERACT PRI_MAX_REALTIME
-#define PRI_MIN_BATCH PRI_MIN_TIMESHARE
+ * 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_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)
Modified: head/sys/kern/subr_sleepqueue.c
==============================================================================
--- head/sys/kern/subr_sleepqueue.c Fri Jan 14 16:42:13 2011 (r217409)
+++ head/sys/kern/subr_sleepqueue.c Fri Jan 14 17:06:54 2011 (r217410)
@@ -745,7 +745,8 @@ sleepq_resume_thread(struct sleepqueue *
/* 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);
/*
Modified: head/sys/sys/priority.h
==============================================================================
--- head/sys/sys/priority.h Fri Jan 14 16:42:13 2011 (r217409)
+++ head/sys/sys/priority.h Fri Jan 14 17:06:54 2011 (r217410)
@@ -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)
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