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Message-ID: <62399b9c-d5ef-4c56-4592-d2cf1af503d6@amd.com>
Date: Thu, 1 Dec 2022 14:43:26 +0530
From: Ravi Bangoria <ravi.bangoria@....com>
To: "Liang, Kan" <kan.liang@...ux.intel.com>
Cc: acme@...nel.org, irogers@...gle.com, jolsa@...hat.com,
namhyung@...nel.org, peterz@...radead.org, mark.rutland@....com,
adrian.hunter@...el.com, alexander.shishkin@...ux.intel.com,
carsten.haitzler@....com, leo.yan@...aro.org, maddy@...ux.ibm.com,
kjain@...ux.ibm.com, atrajeev@...ux.vnet.ibm.com,
tmricht@...ux.ibm.com, linux-perf-users@...r.kernel.org,
linux-kernel@...r.kernel.org, sandipan.das@....com,
ananth.narayan@....com, santosh.shukla@....com,
Ravi Bangoria <ravi.bangoria@....com>
Subject: Re: [PATCH v2 2/2] perf test: Add event group test
Hi Kan,
Thanks for the review.
>> +static int setup_uncore_event(void)
>> +{
>> + struct perf_pmu *pmu;
>> +
>> + if (list_empty(&pmus))
>> + perf_pmu__scan(NULL);
>> +
>> + perf_pmus__for_each_pmu(pmu) {
>> + if (pmu->is_uncore) {
>
> Always using the first uncore PMU may trigger false alarm on some Intel
> platforms. For example, Intel has free running uncore PMUs (e.g.,
> uncore_imc_free_running_0), which only supports special event encoding
> 0xff. The config 0 must fails.
> You may want to add the below check to ignore the free running uncore PMUs.
> if (strstr(pmu->name, "free_running"))
> continue;
>
>
> Also, some uncore PMUs only support two counters. But the test assumes
> that the number of counters > 2. You may want to limit the size of the
> group for 2 for a pure uncore group.
That seems hacky. Instead of ignoring, would it be possible to provide
a list of testable pmus? Example with random values:
/* Uncore pmus that support more than 3 counters */
static struct uncore_pmus {
char *name;
unsigned long config;
} uncore_pmus[] = {
{ "amd_l3", 0x0 },
{ "amd_df", 0x0 },
{ "uncore_imc_xxx", 0xff }, /* Intel */
{ "intel_xxx_pmu2", 0xff }, /* Intel */
{ "abc_pmu1", 0x0 }, /* Arm */
{ "hv_24x7", 0xa }, /* PowerPC */
{ ... },
};
perf_pmus__for_each_pmu(pmu) {
if (pmu present in uncore_pmus[])
type[2] = pmu->type;
config[2] = pmu->config;
}
Ofcourse, this should work for all architectures. Arm, PowerPC, s390 folks?
Thanks,
Ravi
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