The patch titled
Use num_possible_cpus() instead of NR_CPUS for timer distribution
has been removed from the -mm tree. Its filename was
use-num_possible_cpus-instead-of-nr_cpus-for-timer.patch
This patch was dropped because it was merged into mainline or a subsystem tree
------------------------------------------------------
Subject: Use num_possible_cpus() instead of NR_CPUS for timer distribution
From: john stultz <johnstul@xxxxxxxxxx>
To avoid lock contention, we distribute the sched_timer calls across the
cpus so they do not trigger at the same instant. However, I used NR_CPUS,
which can cause needless grouping on small smp systems depending on your
kernel config. This patch converts to using num_possible_cpus() so we
spread it as evenly as possible on every machine.
Briefly tested w/ NR_CPUS=255 and verified reduced contention.
Signed-off-by: John Stultz <johnstul@xxxxxxxxxx>
Acked-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
kernel/time/tick-sched.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff -puN kernel/time/tick-sched.c~use-num_possible_cpus-instead-of-nr_cpus-for-timer kernel/time/tick-sched.c
--- a/kernel/time/tick-sched.c~use-num_possible_cpus-instead-of-nr_cpus-for-timer
+++ a/kernel/time/tick-sched.c
@@ -570,7 +570,7 @@ void tick_setup_sched_timer(void)
/* Get the next period (per cpu) */
ts->sched_timer.expires = tick_init_jiffy_update();
offset = ktime_to_ns(tick_period) >> 1;
- do_div(offset, NR_CPUS);
+ do_div(offset, num_possible_cpus());
offset *= smp_processor_id();
ts->sched_timer.expires = ktime_add_ns(ts->sched_timer.expires, offset);
_
Patches currently in -mm which might be from johnstul@xxxxxxxxxx are
origin.patch
git-acpi.patch
hpet-force-enable-on-vt8235-37-chipsets.patch
fix-discrepancy-between-vdso-based-gettimeofday-and-sys_gettimeofday.patch
kernel-time-clocksourcec-use-list_for_each_entry-instead-of-list_for_each.patch
-
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