Re: [PATCH v3 11/27] perf pmu: Support 'cycles' and 'branches' inside hybrid PMU

Jiri Olsa
2021-04-09T13:48:31Z

On Mon, Mar 29, 2021 at 03:00:30PM +0800, Jin Yao wrote:
> On hybrid platform, user may want to enable the hardware event
> only on one PMU. So following syntax is supported:
>
> cpu_core/<hardware event>/
> cpu_atom/<hardware event>/
>
> # perf stat -e cpu_core/cpu-cycles/ -a -- sleep 1
>
> Performance counter stats for 'system wide':
>
> 6,049,336 cpu_core/cpu-cycles/
>
> 1.003577042 seconds time elapsed
>
> It enables the event 'cpu-cycles' only on cpu_core pmu.
>
> But for 'cycles' and 'branches', the syntax doesn't work.

because the alias is not there.. but there's:
cpu/cpu-cycles/
cpu/branch-instructions/

doing the same thing.. what's wrong with that?

I have a feeling we discussed this in the previous
version.. did I give up? ;-)

SNIP

> diff --git a/tools/perf/util/pmu.c b/tools/perf/util/pmu.c
> index beff29981101..72e5ae5e868e 100644
> --- a/tools/perf/util/pmu.c
> +++ b/tools/perf/util/pmu.c
> @@ -916,6 +916,35 @@ static int pmu_max_precise(const char *name)
> return max_precise;
> }
>
> +static void perf_pmu__add_hybrid_aliases(struct list_head *head)
> +{
> + static struct pmu_event pme_hybrid_fixup[] = {
> + {
> + .name = "cycles",
> + .event = "event=0x3c",
> + },
> + {
> + .name = "branches",
> + .event = "event=0xc4",
> + },
> + {
> + .name = 0,
> + .event = 0,
> + },

if you really need to access these 2 events with special name,
why not add it through the json.. let's not have yet another
place that defines aliases ... also this should be model specific
no?

jirka