Re: [PATCH v8 4/8] perf arm: Refactor event list iteration in auxtrace_record__init()

From: "liuqi (BA)" <liuqi115@huawei.com>
To: Jonathan Cameron <Jonathan.Cameron@Huawei.com>,
	Yicong Yang <yangyicong@hisilicon.com>
Cc: <gregkh@linuxfoundation.org>,
	<alexander.shishkin@linux.intel.com>, <leo.yan@linaro.org>,
	<james.clark@arm.com>, <will@kernel.org>, <robin.murphy@arm.com>,
	<acme@kernel.org>, <john.garry@huawei.com>, <helgaas@kernel.org>,
	<lorenzo.pieralisi@arm.com>, <mathieu.poirier@linaro.org>,
	<suzuki.poulose@arm.com>, <mark.rutland@arm.com>,
	<joro@8bytes.org>, <shameerali.kolothum.thodi@huawei.com>,
	<peterz@infradead.org>, <mingo@redhat.com>,
	<linux-kernel@vger.kernel.org>,
	<linux-arm-kernel@lists.infradead.org>,
	<linux-pci@vger.kernel.org>, <linux-perf-users@vger.kernel.org>,
	<iommu@lists.linux-foundation.org>, <prime.zeng@huawei.com>,
	<zhangshaokun@hisilicon.com>, <linuxarm@huawei.com>
Subject: Re: [PATCH v8 4/8] perf arm: Refactor event list iteration in auxtrace_record__init()
Date: Tue, 17 May 2022 09:35:00 +0800	[thread overview]
Message-ID: <791a4e66-2e55-c97f-cc05-16032d576121@huawei.com> (raw)
In-Reply-To: <20220516151722.0000693a@Huawei.com>


Hi Jonathan,
On 2022/5/16 22:17, Jonathan Cameron wrote:
> On Mon, 16 May 2022 20:52:19 +0800
> Yicong Yang <yangyicong@hisilicon.com> wrote:
> 
>> From: Qi Liu <liuqi115@huawei.com>
>>
>> Use find_pmu_for_event() to simplify logic in auxtrace_record__init().
> Possibly reword as
> 
> "Add find_pmu_for_event() and use to simplify logic in
> auxtrace_record_init(). find_pmu_for_event() will be
> reused in subsequent patches."
> 
thanks, I'll modify the commit message next version.

Thanks,
Qi
>>
>> Signed-off-by: Qi Liu <liuqi115@huawei.com>
>> Signed-off-by: Yicong Yang <yangyicong@hisilicon.com>
> FWIW as this isn't an area I know much about. It seems
> like a good cleanup and functionally equivalent.
> 
> Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
>> ---
>>   tools/perf/arch/arm/util/auxtrace.c | 53 ++++++++++++++++++-----------
>>   1 file changed, 34 insertions(+), 19 deletions(-)
>>
>> diff --git a/tools/perf/arch/arm/util/auxtrace.c b/tools/perf/arch/arm/util/auxtrace.c
>> index 5fc6a2a3dbc5..384c7cfda0fd 100644
>> --- a/tools/perf/arch/arm/util/auxtrace.c
>> +++ b/tools/perf/arch/arm/util/auxtrace.c
>> @@ -50,16 +50,32 @@ static struct perf_pmu **find_all_arm_spe_pmus(int *nr_spes, int *err)
>>   	return arm_spe_pmus;
>>   }
>>   
>> +static struct perf_pmu *find_pmu_for_event(struct perf_pmu **pmus,
>> +					   int pmu_nr, struct evsel *evsel)
>> +{
>> +	int i;
>> +
>> +	if (!pmus)
>> +		return NULL;
>> +
>> +	for (i = 0; i < pmu_nr; i++) {
>> +		if (evsel->core.attr.type == pmus[i]->type)
>> +			return pmus[i];
>> +	}
>> +
>> +	return NULL;
>> +}
>> +
>>   struct auxtrace_record
>>   *auxtrace_record__init(struct evlist *evlist, int *err)
>>   {
>> -	struct perf_pmu	*cs_etm_pmu;
>> +	struct perf_pmu	*cs_etm_pmu = NULL;
>> +	struct perf_pmu **arm_spe_pmus = NULL;
>>   	struct evsel *evsel;
>> -	bool found_etm = false;
>> +	struct perf_pmu *found_etm = NULL;
>>   	struct perf_pmu *found_spe = NULL;
>> -	struct perf_pmu **arm_spe_pmus = NULL;
>> +	int auxtrace_event_cnt = 0;
>>   	int nr_spes = 0;
>> -	int i = 0;
>>   
>>   	if (!evlist)
>>   		return NULL;
>> @@ -68,24 +84,23 @@ struct auxtrace_record
>>   	arm_spe_pmus = find_all_arm_spe_pmus(&nr_spes, err);
>>   
>>   	evlist__for_each_entry(evlist, evsel) {
>> -		if (cs_etm_pmu &&
>> -		    evsel->core.attr.type == cs_etm_pmu->type)
>> -			found_etm = true;
>> -
>> -		if (!nr_spes || found_spe)
>> -			continue;
>> -
>> -		for (i = 0; i < nr_spes; i++) {
>> -			if (evsel->core.attr.type == arm_spe_pmus[i]->type) {
>> -				found_spe = arm_spe_pmus[i];
>> -				break;
>> -			}
>> -		}
>> +		if (cs_etm_pmu && !found_etm)
>> +			found_etm = find_pmu_for_event(&cs_etm_pmu, 1, evsel);
>> +
>> +		if (arm_spe_pmus && !found_spe)
>> +			found_spe = find_pmu_for_event(arm_spe_pmus, nr_spes, evsel);
>>   	}
>> +
>>   	free(arm_spe_pmus);
>>   
>> -	if (found_etm && found_spe) {
>> -		pr_err("Concurrent ARM Coresight ETM and SPE operation not currently supported\n");
>> +	if (found_etm)
>> +		auxtrace_event_cnt++;
>> +
>> +	if (found_spe)
>> +		auxtrace_event_cnt++;
>> +
>> +	if (auxtrace_event_cnt > 1) {
>> +		pr_err("Concurrent AUX trace operation not currently supported\n");
>>   		*err = -EOPNOTSUPP;
>>   		return NULL;
>>   	}
> 
> .
>