From: "Jin, Yao" <yao.jin@linux.intel.com>
To: John Garry <john.garry@huawei.com>,
Arnaldo Carvalho de Melo <acme@kernel.org>,
Jiri Olsa <jolsa@kernel.org>,
Kan Liang <kan.liang@linux.intel.com>
Cc: "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"linux-perf-users@vger.kernel.org"
<linux-perf-users@vger.kernel.org>,
Zhangshaokun <zhangshaokun@hisilicon.com>,
"liuqi (BA)" <liuqi115@huawei.com>,
Andi Kleen <ak@linux.intel.com>, "Jin, Yao" <yao.jin@intel.com>
Subject: Re: [bug report] Patch "perf tools: Fix pattern matching for same substring in different pmu type" broken
Date: Tue, 20 Jul 2021 13:56:49 +0800 [thread overview]
Message-ID: <1522c39e-5658-d030-2e1e-f6e5d849d29b@linux.intel.com> (raw)
In-Reply-To: <44e25825-5f23-c641-9f1c-72268d895f75@huawei.com>
Hi John, Hi Arnaldo,
On 7/19/2021 10:13 PM, John Garry wrote:
> Hi guys,
>
> The named patch has broken PMU alias matching on my arm64 system.
>
> Specifically it is broken for when multiple tokens are used in the alias. For example, alias
> "hisi_sccl,l3c" would previously match for PMU "hisi_sccl3_l3c7", but that no longer works.
>
> In my example, in looking at the code, the callchain pmu_uncore_alias_match("hisi_sccl,l3c",
> "hisi_sccl3_l3c7") -> per_pmu__valid_suffix("hisi_sccl3_l3c7", "hisi_sccl") fails in the following
> check:
>
> static bool perf_pmu__valid_suffix(char *pmu_name, char *tok)
> {
> char *p;
> ...
> p = pmu_name + strlen(tok);
> ...
> if (*p != '_') //here
> return false;
> }
>
> This check assumes the first token must be followed by a '_', but it is possibly a numeric.
>
It looks that the PMU alias format on arm64 has big difference than the format on x86. My new idea
is we create a x86 specific perf_pmu__valid_suffix, and for other arch, the weak function always
returns true. That will not change original behavior.
What do you think?
> Please let me know how this should work. Previously it would match on the tokens, ignoring numerics
> and '_'.
>
> As an aside, I'll look at why our testcases don't cover this scenario and look to add a test if
> necessary.
>
> Thanks,
> john
>
> Ps, please cc linux-perf-users@vger.kernel.org as in the MAINTAINERS file in future, as not all
> subscribe to the open kernel list (and so cannot easily reply directly).
>
Sorry about that! I will remember that, cc linux-perf-users@vger.kernel.org in next patch.
Thanks
Jin Yao
prev parent reply other threads:[~2021-07-20 5:56 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-07-19 14:13 [bug report] Patch "perf tools: Fix pattern matching for same substring in different pmu type" broken John Garry
2021-07-19 20:01 ` Arnaldo Carvalho de Melo
2021-07-20 5:56 ` Jin, Yao [this message]
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