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Message-ID: <14a70048-ddd0-3297-9ae9-6b76dd0f1000@linux.intel.com>
Date: Mon, 28 Jun 2021 09:52:42 +0800
From: "Jin, Yao" <yao.jin@...ux.intel.com>
To: Jiri Olsa <jolsa@...hat.com>
Cc: acme@...nel.org, jolsa@...nel.org, peterz@...radead.org,
mingo@...hat.com, alexander.shishkin@...ux.intel.com,
Linux-kernel@...r.kernel.org, ak@...ux.intel.com,
kan.liang@...el.com, yao.jin@...el.com
Subject: Re: [PATCH v1] perf tools: Fix pattern matching for same substring
used in different pmu type
Hi Jiri,
On 6/25/2021 6:11 PM, Jiri Olsa wrote:
> On Wed, Jun 23, 2021 at 10:02:01AM +0800, Jin, Yao wrote:
>> Hi Arnaldo, Jiri,
>>
>> Any comments for this bug fix patch?
>>
>> The issue does impact some uncore events and even some metrics.
>
> sry for delay
>
> SNIP
>
>>>> Some different pmu types may have same substring. For example,
>>>> on Icelake server, we have pmu types "uncore_imc" and
>>>> "uncore_imc_free_running". Both pmu types have substring "uncore_imc".
>>>> But the parser would wrongly think they are the same pmu type.
>>>>
>>>> We enable an imc event,
>>>> perf stat -e uncore_imc/event=0xe3/ -a -- sleep 1
>>>>
>>>> Perf actually expands the event to:
>>>> uncore_imc_0/event=0xe3/
>>>> uncore_imc_1/event=0xe3/
>>>> uncore_imc_2/event=0xe3/
>>>> uncore_imc_3/event=0xe3/
>>>> uncore_imc_4/event=0xe3/
>>>> uncore_imc_5/event=0xe3/
>>>> uncore_imc_6/event=0xe3/
>>>> uncore_imc_7/event=0xe3/
>>>> uncore_imc_free_running_0/event=0xe3/
>>>> uncore_imc_free_running_1/event=0xe3/
>>>> uncore_imc_free_running_3/event=0xe3/
>>>> uncore_imc_free_running_4/event=0xe3/
>>>>
>>>> That's because the "uncore_imc_free_running" matches the
>>>> pattern "uncore_imc*".
>>>>
>>>> Now we check that the last characters of pmu name is
>>>> '_<digit>'.
>>>>
>>>> Fixes: b2b9d3a3f021 ("perf pmu: Support wildcards on pmu name in dynamic pmu events")
>>>> Signed-off-by: Jin Yao <yao.jin@...ux.intel.com>
>>>> ---
>>>> tools/perf/util/parse-events.y | 2 ++
>>>> tools/perf/util/pmu.c | 25 ++++++++++++++++++++++++-
>>>> tools/perf/util/pmu.h | 1 +
>>>> 3 files changed, 27 insertions(+), 1 deletion(-)
>>>>
>>>> diff --git a/tools/perf/util/parse-events.y b/tools/perf/util/parse-events.y
>>>> index aba12a4d488e..7a694c7f7f1a 100644
>>>> --- a/tools/perf/util/parse-events.y
>>>> +++ b/tools/perf/util/parse-events.y
>>>> @@ -317,6 +317,8 @@ event_pmu_name opt_pmu_config
>>>> strncmp($1, "uncore_", 7))
>>>> name += 7;
>>>> if (!fnmatch(pattern, name, 0)) {
>>>> + if (!perf_pmu__valid_suffix($1, name))
>>>> + continue;
>
> could this be part of the fnmatch's pattern?
>
Actually I had used the pattern "uncore_imc_[0-9]" before. But for some units, e.g., CHA, they have
more than 10 units. So this simple pattern couldn't satisfy them.
And then I changed the pattern to "uncore_imc_[0-9]+$", which can match the string
"uncore_imc_<integer id>". But unfortunately it didn't work for fnmatch.
I used regex, such as:
asprintf(&pattern, "%s_[0-9]+$", tok);
regcomp(®ex, pattern, REG_EXTENDED);
ret = regexec(®ex, name, 0, NULL, 0);
But the regex approach looks not very simple (a bit heavy), so finally I just keep using fnmatch and
then just check the last character.
>>>> if (parse_events_copy_term_list(orig_terms, &terms))
>>>> CLEANUP_YYABORT;
>>>> if (!parse_events_add_pmu(_parse_state, list, pmu->name, terms, true, false))
>>>> diff --git a/tools/perf/util/pmu.c b/tools/perf/util/pmu.c
>>>> index 88c8ecdc60b0..78af01959830 100644
>>>> --- a/tools/perf/util/pmu.c
>>>> +++ b/tools/perf/util/pmu.c
>>>> @@ -3,6 +3,7 @@
>>>> #include <linux/compiler.h>
>>>> #include <linux/string.h>
>>>> #include <linux/zalloc.h>
>>>> +#include <linux/ctype.h>
>>>> #include <subcmd/pager.h>
>>>> #include <sys/types.h>
>>>> #include <errno.h>
>>>> @@ -768,7 +769,7 @@ bool pmu_uncore_alias_match(const char *pmu_name, const char *name)
>>>> */
>>>> for (; tok; name += strlen(tok), tok = strtok_r(NULL, ",", &tmp)) {
>>>> name = strstr(name, tok);
>>>> - if (!name) {
>>>> + if (!name || !perf_pmu__valid_suffix(tok, (char *)name)) {
>>>> res = false;
>>>> goto out;
>>>> }
>>>> @@ -1872,3 +1873,25 @@ bool perf_pmu__has_hybrid(void)
>>>> return !list_empty(&perf_pmu__hybrid_pmus);
>>>> }
>>>> +
>>>> +bool perf_pmu__valid_suffix(char *tok, char *pmu_name)
>>>> +{
>>>> + char *p;
>>>> +
>>>> + /*
>>>> + * The pmu_name has substring tok. If the format of
>>>> + * pmu_name is <tok> or <tok>_<digit>, return true.
>>>> + */
>>>> + p = pmu_name + strlen(tok);
>>>> + if (*p == 0)
>>>> + return true;
>>>> +
>>>> + if (*p != '_')
>>>> + return false;
>>>> +
>>>> + ++p;
>>>> + if (*p == 0 || !isdigit(*p))
>>>> + return false;
>>>> +
>>>> + return true;
>>>> +}
>
> hum, so we have pattern serch and then another function checking
> if that search was ok..
Yes, that's what this patch does.
I understand that's convenient, because
> it's on 2 different places
Yes, on pmu_uncore_alias_match() and on parse-events.y.
but could we have some generic solution,
> line one function/search that returns/search for valid pmu name?
>
Sorry, I don't understand this idea well. Would you like to further explain?
Or can you accept the regex approach?
> thanks,
> jirka
>
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