Messages in this thread Patch in this message | | | Date | Wed, 25 May 2022 14:31:29 -0300 | From | Marcelo Tosatti <> | Subject | Re: [PATCH v2] cpuidle: haltpoll: Add trace points for guest_halt_poll_ns grow/shrink |
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On Mon, May 23, 2022 at 11:53:32PM +0000, Eiichi Tsukata wrote: > Add trace points as are implemented in KVM host halt polling. > This helps tune guest halt polling params. > > Signed-off-by: Eiichi Tsukata <eiichi.tsukata@nutanix.com> > --- > drivers/cpuidle/governors/haltpoll.c | 15 ++++++++----- > include/trace/events/power.h | 33 ++++++++++++++++++++++++++++ > 2 files changed, 43 insertions(+), 5 deletions(-) > > diff --git a/drivers/cpuidle/governors/haltpoll.c b/drivers/cpuidle/governors/haltpoll.c > index cb2a96eafc02..a5b6ad32956c 100644 > --- a/drivers/cpuidle/governors/haltpoll.c > +++ b/drivers/cpuidle/governors/haltpoll.c > @@ -19,6 +19,7 @@ > #include <linux/sched.h> > #include <linux/module.h> > #include <linux/kvm_para.h> > +#include <trace/events/power.h> > > static unsigned int guest_halt_poll_ns __read_mostly = 200000; > module_param(guest_halt_poll_ns, uint, 0644); > @@ -77,13 +78,16 @@ static int haltpoll_select(struct cpuidle_driver *drv, > > static void adjust_poll_limit(struct cpuidle_device *dev, u64 block_ns) > { > - unsigned int val; > + unsigned int val, old; > > - /* Grow cpu_halt_poll_us if > - * cpu_halt_poll_us < block_ns < guest_halt_poll_us > + val = dev->poll_limit_ns; > + old = val; > + > + /* Grow poll_limit_ns if > + * poll_limit_ns < block_ns < guest_halt_poll_ns > */ > if (block_ns > dev->poll_limit_ns && block_ns <= guest_halt_poll_ns) { > - val = dev->poll_limit_ns * guest_halt_poll_grow; > + val *= guest_halt_poll_grow; > > if (val < guest_halt_poll_grow_start) > val = guest_halt_poll_grow_start; > @@ -91,16 +95,17 @@ static void adjust_poll_limit(struct cpuidle_device *dev, u64 block_ns) > val = guest_halt_poll_ns; >
Can do it before the assignment:
trace_guest_halt_poll_ns_grow(val, dev->poll_limit_ns);
> dev->poll_limit_ns = val; > + trace_guest_halt_poll_ns_grow(smp_processor_id(), val, old); > } else if (block_ns > guest_halt_poll_ns && > guest_halt_poll_allow_shrink) { > unsigned int shrink = guest_halt_poll_shrink; > > - val = dev->poll_limit_ns; > if (shrink == 0) > val = 0; > else > val /= shrink; > dev->poll_limit_ns = val; > + trace_guest_halt_poll_ns_shrink(smp_processor_id(), val, old); > } > } > > diff --git a/include/trace/events/power.h b/include/trace/events/power.h > index af5018aa9517..db065af9c3c0 100644 > --- a/include/trace/events/power.h > +++ b/include/trace/events/power.h > @@ -500,6 +500,39 @@ DEFINE_EVENT(dev_pm_qos_request, dev_pm_qos_remove_request, > > TP_ARGS(name, type, new_value) > ); > + > +TRACE_EVENT(guest_halt_poll_ns, > + > + TP_PROTO(bool grow, unsigned int cpu_id, > + unsigned int new, unsigned int old), > + > + TP_ARGS(grow, cpu_id, new, old), > + > + TP_STRUCT__entry( > + __field(bool, grow) > + __field(unsigned int, cpu_id) > + __field(unsigned int, new) > + __field(unsigned int, old) > + ), > + > + TP_fast_assign( > + __entry->grow = grow; > + __entry->cpu_id = cpu_id; > + __entry->new = new; > + __entry->old = old; > + ), > + > + TP_printk("cpu %u: halt_poll_ns %u (%s %u)", > + __entry->cpu_id, > + __entry->new, > + __entry->grow ? "grow" : "shrink", > + __entry->old) > +); > + > +#define trace_guest_halt_poll_ns_grow(cpu_id, new, old) \ > + trace_guest_halt_poll_ns(true, cpu_id, new, old) > +#define trace_guest_halt_poll_ns_shrink(cpu_id, new, old) \ > + trace_guest_halt_poll_ns(false, cpu_id, new, old) > #endif /* _TRACE_POWER_H */ > > /* This part must be outside protection */ > -- > 2.36.1 > >
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