Messages in this thread | | | Date | Wed, 28 Mar 2012 08:47:15 +0200 | Subject | Re: [RFC][PATCH 00/32] Nohz cpusets v2 (adaptive tickless kernel) | From | Gilad Ben-Yossef <> |
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On Tue, Mar 27, 2012 at 6:22 PM, Christoph Lameter <cl@linux.com> wrote: > On Tue, 27 Mar 2012, Gilad Ben-Yossef wrote: > >> +static void vmstat_update(struct work_struct *w) >> +{ >> + int cpu, this_cpu = smp_processor_id(); >> + int sleepy_cpu_counter = 0; >> + static spinlock_t lock; >> + >> + if(spin_trylock(&lock)) { > > Trylock would cause cache bouncing between vmstat runs on various > processors. The reason that vmstat_update exists is to avoid these cache > bounces. Please no exclusive cacheline acquisiton by all cpus by default. >
Right, I didn't think of that.
> The best method would be to assign a sacrifical lamb cpu and check if we > are running on that cpu. That way taking a lock can be avoided.
Cool, I'll do it.
Thanks
Gilad
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-- Gilad Ben-Yossef Chief Coffee Drinker gilad@benyossef.com Israel Cell: +972-52-8260388 US Cell: +1-973-8260388 http://benyossef.com
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