linux-kernel - Re: [PATCH v2 1/5] perf pmu: Fix uncore PMU alias list for ARM64

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Message-ID: <275d1699-23a3-f06b-3fad-750784318cc1@huawei.com>
Date:   Fri, 14 Jun 2019 16:04:26 +0100
From:   John Garry <john.garry@...wei.com>
To:     Arnaldo Carvalho de Melo <arnaldo.melo@...il.com>
CC:     <peterz@...radead.org>, <mingo@...hat.com>,
        <alexander.shishkin@...ux.intel.com>, <jolsa@...hat.com>,
        <namhyung@...nel.org>, <tmricht@...ux.ibm.com>,
        <brueckner@...ux.ibm.com>, <kan.liang@...ux.intel.com>,
        <ben@...adent.org.uk>, <mathieu.poirier@...aro.org>,
        <mark.rutland@....com>, <will.deacon@....com>,
        <linux-kernel@...r.kernel.org>, <linuxarm@...wei.com>,
        <linux-arm-kernel@...ts.infradead.org>,
        <zhangshaokun@...ilicon.com>
Subject: Re: [PATCH v2 1/5] perf pmu: Fix uncore PMU alias list for ARM64

On 14/06/2019 15:46, Arnaldo Carvalho de Melo wrote:
> Em Fri, Jun 14, 2019 at 10:07:59PM +0800, John Garry escreveu:
>> In commit 292c34c10249 ("perf pmu: Fix core PMU alias list for X86
>> platform"), we fixed the issue of CPU events being aliased to uncore
>> events.
>>
>> Fix this same issue for ARM64, since the said commit left the (broken)
>> behaviour untouched for ARM64.
>
> So I added:
>
> Cc: stable@...r.kernel.org
> Fixes: 292c34c10249 ("perf pmu: Fix core PMU alias list for X86 platform")
>
> So that the stable trees get this fix and add it to the versions where
> it should have been together with the x86 fix, ok?

Hi Arnaldo,

I have a slight hesitation about this qualifying for the stable.

It's fixing uncore pmu aliasing for arm64. But this series is also the 
first to introduce any actual arm64 uncore pmu aliases.

Thanks,
John

>
> - Arnaldo
>
>> Signed-off-by: John Garry <john.garry@...wei.com>
>> ---
>>  tools/perf/util/pmu.c | 28 ++++++++++++----------------
>>  1 file changed, 12 insertions(+), 16 deletions(-)
>>
>> diff --git a/tools/perf/util/pmu.c b/tools/perf/util/pmu.c
>> index f2eff272279b..7e7299fee550 100644
>> --- a/tools/perf/util/pmu.c
>> +++ b/tools/perf/util/pmu.c
>> @@ -709,9 +709,7 @@ static void pmu_add_cpu_aliases(struct list_head *head, struct perf_pmu *pmu)
>>  {
>>  	int i;
>>  	struct pmu_events_map *map;
>> -	struct pmu_event *pe;
>>  	const char *name = pmu->name;
>> -	const char *pname;
>>
>>  	map = perf_pmu__find_map(pmu);
>>  	if (!map)
>> @@ -722,28 +720,26 @@ static void pmu_add_cpu_aliases(struct list_head *head, struct perf_pmu *pmu)
>>  	 */
>>  	i = 0;
>>  	while (1) {
>> +		const char *cpu_name = is_arm_pmu_core(name) ? name : "cpu";
>> +		struct pmu_event *pe = &map->table[i++];
>> +		const char *pname = pe->pmu ? pe->pmu : cpu_name;
>>
>> -		pe = &map->table[i++];
>>  		if (!pe->name) {
>>  			if (pe->metric_group || pe->metric_name)
>>  				continue;
>>  			break;
>>  		}
>>
>> -		if (!is_arm_pmu_core(name)) {
>> -			pname = pe->pmu ? pe->pmu : "cpu";
>> -
>> -			/*
>> -			 * uncore alias may be from different PMU
>> -			 * with common prefix
>> -			 */
>> -			if (pmu_is_uncore(name) &&
>> -			    !strncmp(pname, name, strlen(pname)))
>> -				goto new_alias;
>> +		/*
>> +		 * uncore alias may be from different PMU
>> +		 * with common prefix
>> +		 */
>> +		if (pmu_is_uncore(name) &&
>> +		    !strncmp(pname, name, strlen(pname)))
>> +			goto new_alias;
>>
>> -			if (strcmp(pname, name))
>> -				continue;
>> -		}
>> +		if (strcmp(pname, name))
>> +			continue;
>>
>>  new_alias:
>>  		pr_err("%s new_alias name=%s pe->name=%s\n", __func__, name, pe->name);
>> --
>> 2.17.1
>