Re: [PATCH] sched: cpuacct: Use bigger percpu counter batch values for stats counters

KOSAKI Motohiro
2010-01-25T23:44:43Z

> On Mon, 18 Jan 2010 15:41:42 +1100
> Anton Blanchard <anton@samba.org> wrote:
>
> > When CONFIG_VIRT_CPU_ACCOUNTING and CONFIG_CGROUP_CPUACCT are enabled we can
> > call cpuacct_update_stats with values much larger than percpu_counter_batch.
> > This means the call to percpu_counter_add will always add to the global count
> > which is protected by a spinlock and we end up with a global spinlock in
> > the scheduler.
>
> When one looks at the end result:

We have about 32 jiffies batch both with or without CONFIG_VIRT_CPU_ACCOUNTING.
Then, The enduser can looks some jiffies after.