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SubjectRe: [PATCH v2 2/2] perf tools: Fix pattern matching for same substring in different pmu type
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On 6/30/2021 8:09 AM, Jin Yao wrote:
> 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>'.
>
> For pattern "uncore_imc*", "uncore_imc_0" is parsed ok,
> but "uncore_imc_free_running_0" is failed.
>
> Fixes: b2b9d3a3f021 ("perf pmu: Support wildcards on pmu name in dynamic pmu events")
> Signed-off-by: Jin Yao <yao.jin@linux.intel.com>
> ---
> tools/perf/util/pmu.c | 28 +++++++++++++++++++++++++++-
> 1 file changed, 27 insertions(+), 1 deletion(-)
>
> diff --git a/tools/perf/util/pmu.c b/tools/perf/util/pmu.c
> index 96f5ff9b5440..9ee123d77e6d 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>
> @@ -741,6 +742,28 @@ struct pmu_events_map *__weak pmu_events_map__find(void)
> return perf_pmu__find_map(NULL);
> }
>
> +static bool perf_pmu__valid_suffix(char *tok, char *pmu_name)
> +{
> + char *p;
> +
> + /*
> + * The pmu_name has substring tok. If the format of

The uncore PMU may have two names, e.g., uncore_cha_Y or
uncore_type_X_Y. User can use either name. I don't think we can assume
that the pmu_name has substring tok. I think we should add a check as below.


@@ -746,6 +746,8 @@ static bool perf_pmu__valid_suffix(char *tok, char
*pmu_name)
{
char *p;

+ if (strncmp(pmu_name, tok, strlen(tok)))
+ return false;
/*
* The pmu_name has substring tok. If the format of
* pmu_name is tok or tok_digit, return true.

> + * 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;
> +}
> +
> bool pmu_uncore_alias_match(const char *pmu_name, const char *name)
> {
> char *tmp = NULL, *tok, *str;
> @@ -769,7 +792,7 @@ 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;
> }
> @@ -1886,5 +1909,8 @@ int perf_pmu__pattern_match(struct perf_pmu *pmu, char *pattern, char *tok)
> if (fnmatch(pattern, name, 0))
> return -1;
>
> + if (!perf_pmu__valid_suffix(tok, name))
> + return -1;
> +

They are still two functions. I'm wondering if we can merge the two
functions to one function, e.g., perf_pmu_match()?

So my patch just need to simply do
if (!perf_pmu_match(tok, name) && !perf_pmu_match(tok,
pmu->alias_name)) return -1;

Thanks,
Kan
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