Re: [PATCH v9 3/5] perf utils: use pmu->is_uncore to detect PMU UNCORE devices

Jin, Yao
2017-12-05T02:12:19Z

Hi Kulkarni, Arnaldo,

This patch has been merged in perf/core branch today.

But I see a regression issue when I run the 'perf stat'.

With bisect checking, I locate to this patch.

commit ad8737a08973f5dca632bdd63cf2abc99670e540
Author: Ganapatrao Kulkarni <ganapatrao.kulkarni@cavium.com>
Date: Tue Oct 17 00:02:20 2017 +0530

perf pmu: Use pmu->is_uncore to detect UNCORE devices

For example (on Intel skylake desktop),

1. The correct output should be (without this patch):

root@skl:/tmp# perf stat --per-thread -p 1754 -M CPI,IPC
^C
Performance counter stats for process id '1754':

vmstat-1754 1,882,798 inst_retired.any
# 0.8 CPI
vmstat-1754 1,589,720 cycles
vmstat-1754 1,882,798 inst_retired.any
# 1.2 IPC
vmstat-1754 1,589,720 cpu_clk_unhalted.thread

2.647443167 seconds time elapsed

2. With this patch, the output will be:

root@skl:/tmp# perf stat --per-thread -p 1754 -M CPI,IPC
^C
Performance counter stats for process id '1754':

vmstat-1754 1,945,589 inst_retired.any
vmstat-1754 <not supported> inst_retired.any
vmstat-1754 1,609,892 cycles
vmstat-1754 1,945,589 inst_retired.any
vmstat-1754 <not supported> inst_retired.any
vmstat-1754 1,609,892 cpu_clk_unhalted.thread
vmstat-1754 <not supported> cpu_clk_unhalted.thread

3.051274166 seconds time elapsed

Could you please help to take a look?

Thanks
Jin Yao

On 10/17/2017 2:32 AM, Ganapatrao Kulkarni wrote:
> PMU CORE devices are identified using sysfs filename cpu, however
> on some platforms(like arm/arm64), PMU CORE sysfs name is not cpu.
> Hence cpu cannot be used to differentiate PMU CORE/UNCORE devices.
>
> commit:
> 66ec1191 ("perf pmu: Unbreak perf record for arm/arm64 with events with explicit PMU")
>
> has introduced pmu->is_uncore, which is set to PMU UNCORE devices only.
> Adding changes to use pmu->is_uncore to identify UNCORE devices.
>
> Acked-by: Will Deacon <will.deacon@arm.com>
> Tested-by: Shaokun Zhang <zhangshaokun@hisilicon.com>
> Signed-off-by: Ganapatrao Kulkarni <ganapatrao.kulkarni@cavium.com>
> ---
> tools/perf/util/pmu.c | 11 +++++++----
> 1 file changed, 7 insertions(+), 4 deletions(-)
>
> diff --git a/tools/perf/util/pmu.c b/tools/perf/util/pmu.c
> index 8b17db5..9110718 100644
> --- a/tools/perf/util/pmu.c
> +++ b/tools/perf/util/pmu.c
> @@ -603,7 +603,6 @@ static void pmu_add_cpu_aliases(struct list_head *head, struct perf_pmu *pmu)
> */
> i = 0;
> while (1) {
> - const char *pname;
>
> pe = &map->table[i++];
> if (!pe->name) {
> @@ -612,9 +611,13 @@ static void pmu_add_cpu_aliases(struct list_head *head, struct perf_pmu *pmu)
> break;
> }
>
> - pname = pe->pmu ? pe->pmu : "cpu";
> - if (strncmp(pname, name, strlen(pname)))
> - continue;
> + if (pmu->is_uncore) {
> + /* check for uncore devices */
> + if (pe->pmu == NULL)
> + continue;
> + if (strncmp(pe->pmu, name, strlen(pe->pmu)))
> + continue;
> + }
>
> /* need type casts to override 'const' */
> __perf_pmu__new_alias(head, NULL, (char *)pe->name,
>