Messages in this thread | | | Date | Fri, 20 Aug 2021 18:18:14 +0800 | From | Jisheng Zhang <> | Subject | Re: [PATCH v2] timer: Use static_branch_likely() for timers_nohz_active |
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On Tue, 10 Aug 2021 18:00:16 +0200 Thomas Gleixner wrote:
> > > Jisheng,
Hi Thomas,
> > On Thu, Jun 24 2021 at 16:32, Jisheng Zhang wrote: > > > The static key timers_nohz_active is likely to be true, so use > > static_branch_likely() to reflect this fact. > > you still lack any justification for your statement that NOHZ active is > likely.
This patch only affects NO_HZ_COMMON=y code path which is enabled if either NO_HZ_IDLE or NO_HZ_FULL = y. Per my understanding, when the system has oneshot tick device, NOHZ active is likely true. After going through drivers/clocksource/*, I found there are about 86 drivers, 69(occupies 80%) of which support CLOCK_EVT_FEAT_ONESHOT. Then I browsed apic, hpet and xen timer source code in x86 directory, they all support oneshot feature.
I'm not sure whether I misunderstood the code or not.
Thanks
> > It might be likely for your system, but is this true in general? >
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