On Wed, 2007-08-15 at 15:46 -0700, john stultz wrote: > Andrew requested this fixup awhile back, and I just now got to it > (apologies for being slow). > > 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 <[EMAIL PROTECTED]>
Doh, I missed this as well Acked-by: Thomas Gleixner <[EMAIL PROTECTED],de> > > Index: 2.6-rt/kernel/time/tick-sched.c > =================================================================== > --- 2.6-rt.orig/kernel/time/tick-sched.c > +++ 2.6-rt/kernel/time/tick-sched.c > @@ -586,7 +586,7 @@ 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); - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
