Re: Re: [PATCH 6/7] drivers/perf: hisi_pcie: Merge find_related_event() and get_event_idx()

[hejunhao]

Hi, Jonathan


On 2024/2/8 20:39, Jonathan Cameron wrote:
> On Sun, 4 Feb 2024 15:45:26 +0800
> Yicong Yang <yangyicong@xxxxxxxxxx> wrote:
>
> > From: Junhao He <hejunhao3@xxxxxxxxxx>
> >
> > The function xxx_find_related_event() scan all working events to find
> > related events. During this process, we also can find the idle counters.
> > If not found related events, return the first idle counter to simplify
> > the code.
> >
> > Signed-off-by: Junhao He <hejunhao3@xxxxxxxxxx>
> > Signed-off-by: Yicong Yang <yangyicong@xxxxxxxxxxxxx>
> A suggestion inline to avoid the magic HISI_PCIE_MAX_COUNTER value
> being used outside of the function.

Thanks for the comments, will fix in next version.

> > ---
> >   drivers/perf/hisilicon/hisi_pcie_pmu.c | 55 ++++++++++----------------
> >   1 file changed, 21 insertions(+), 34 deletions(-)
> >
> > diff --git a/drivers/perf/hisilicon/hisi_pcie_pmu.c b/drivers/perf/hisilicon/hisi_pcie_pmu.c
> > index 1b45aeb82859..2edde66675e7 100644
> > --- a/drivers/perf/hisilicon/hisi_pcie_pmu.c
> > +++ b/drivers/perf/hisilicon/hisi_pcie_pmu.c
> > @@ -397,16 +397,24 @@ static u64 hisi_pcie_pmu_read_counter(struct perf_event *event)
> >   	return hisi_pcie_pmu_readq(pcie_pmu, event->hw.event_base, idx);
> >   }
> >   
> > -static int hisi_pcie_pmu_find_related_event(struct hisi_pcie_pmu *pcie_pmu,
> > -					    struct perf_event *event)
> > +/*
> > + * Check all work events, if a relevant event is found then we return it
> > + * first, otherwise return the first idle counter (need to reset).
> > + */
> > +static int hisi_pcie_pmu_get_event_idx(struct hisi_pcie_pmu *pcie_pmu,
> > +					struct perf_event *event)
> >   {
> > +	int first_idle = HISI_PCIE_MAX_COUNTERS;
> 	int first_idle = -EAGAIN;

Yes, I will do that.

> >   	struct perf_event *sibling;
> >   	int idx;
> >   
> >   	for (idx = 0; idx < HISI_PCIE_MAX_COUNTERS; idx++) {
> >   		sibling = pcie_pmu->hw_events[idx];
> > -		if (!sibling)
> > +		if (!sibling) {
> > +			if (first_idle == HISI_PCIE_MAX_COUNTERS)
> if (first_idle == -EAGAIN)

Ok, will fix it.

> > +				first_idle = idx;
> >   			continue;
> > +		}
> >   
> >   		/* Related events must be used in group */
> >   		if (hisi_pcie_pmu_cmp_event(sibling, event) &&
> > @@ -414,19 +422,7 @@ static int hisi_pcie_pmu_find_related_event(struct hisi_pcie_pmu *pcie_pmu,
> >   			return idx;
> >   	}
> >   
> > -	return idx;
> > -}
> > -
> > -static int hisi_pcie_pmu_get_event_idx(struct hisi_pcie_pmu *pcie_pmu)
> > -{
> > -	int idx;
> > -
> > -	for (idx = 0; idx < HISI_PCIE_MAX_COUNTERS; idx++) {
> > -		if (!pcie_pmu->hw_events[idx])
> > -			return idx;
> > -	}
> > -
> > -	return -EINVAL;
> > +	return first_idle;
> Then this will return -EAGAIN;

Okay

> >   }
> >   
> >   static void hisi_pcie_pmu_event_update(struct perf_event *event)
> > @@ -552,27 +548,18 @@ static int hisi_pcie_pmu_add(struct perf_event *event, int flags)
> >   
> >   	hwc->state = PERF_HES_STOPPED | PERF_HES_UPTODATE;
> >   
> > -	/* Check all working events to find a related event. */
> > -	idx = hisi_pcie_pmu_find_related_event(pcie_pmu, event);
> > -	if (idx < 0)
> > -		return idx;
> > -
> > -	/* Current event shares an enabled counter with the related event */
> > -	if (idx < HISI_PCIE_MAX_COUNTERS) {
> > -		hwc->idx = idx;
> > -		goto start_count;
> > -	}
> > -
> > -	idx = hisi_pcie_pmu_get_event_idx(pcie_pmu);
> > -	if (idx < 0)
> > -		return idx;
> > +	idx = hisi_pcie_pmu_get_event_idx(pcie_pmu, event);
> > +	if (idx == HISI_PCIE_MAX_COUNTERS)
> > +		return -EAGAIN;
> Perhaps simpler to handle first_idle == HISI_PCIE_MAX_COUNTERS as
> an error return in hisi_pcie_pmu_get_event_idx - see above.
>
>   	if (idx < 0)
> 		return idx;

Sure.

> >   
> >   	hwc->idx = idx;
> > -	pcie_pmu->hw_events[idx] = event;
> > -	/* Reset Counter to avoid previous statistic interference. */
> > -	hisi_pcie_pmu_reset_counter(pcie_pmu, idx);
> >   
> > -start_count:
> > +	/* No enabled counter found with related event, reset it */
> > +	if (!pcie_pmu->hw_events[idx]) {
> > +		hisi_pcie_pmu_reset_counter(pcie_pmu, idx);
> > +		pcie_pmu->hw_events[idx] = event;
> > +	}
> > +
> >   	if (flags & PERF_EF_START)
> >   		hisi_pcie_pmu_start(event, PERF_EF_RELOAD);
> >