Re: [PATCH v3 1/4] perf pmu: Support more complex PMU event aliasing

From: Arnaldo Carvalho de Melo
Date: Tue Jul 02 2019 - 15:07:31 EST


Em Fri, Jun 28, 2019 at 10:35:49PM +0800, John Garry escreveu:
> The jevent "Unit" field is used for uncore PMU alias definition.
>
> The form uncore_pmu_example_X is supported, where "X" is a wildcard,
> to support multiple instances of the same PMU in a system.
>
> Unfortunately this format not suitable for all uncore PMUs; take the Hisi
> DDRC uncore PMU for example, where the name is in the form
> hisi_scclX_ddrcY.
>
> For for current jevent parsing, we would be required to hardcode an uncore
> alias translation for each possible value of X. This is not scalable.
>
> Instead, add support for "Unit" field in the form "hisi_sccl,ddrc", where
> we can match by hisi_scclX and ddrcY. Tokens in Unit field
> are delimited by ','.
>
> Signed-off-by: John Garry <john.garry@xxxxxxxxxx>
> ---
> tools/perf/util/pmu.c | 46 ++++++++++++++++++++++++++++++++++++++-----
> 1 file changed, 41 insertions(+), 5 deletions(-)
>
> diff --git a/tools/perf/util/pmu.c b/tools/perf/util/pmu.c
> index 7e7299fee550..cfc916819c59 100644
> --- a/tools/perf/util/pmu.c
> +++ b/tools/perf/util/pmu.c
> @@ -700,6 +700,46 @@ struct pmu_events_map *perf_pmu__find_map(struct perf_pmu *pmu)
> return map;
> }
>
> +static bool pmu_uncore_alias_match(const char *pmu_name, const char *name)
> +{
> + char *tmp, *tok, *str;
> + bool res;
> +
> + str = strdup(pmu_name);
> + if (!str)
> + return false;
> +
> + /*
> + * uncore alias may be from different PMU with common prefix
> + */
> + tok = strtok_r(str, ",", &tmp);

In some places, e.g. gcc version 4.1.2:

CC /tmp/build/perf/util/pmu.o
cc1: warnings being treated as errors
util/pmu.c: In function âpmu_lookupâ:
util/pmu.c:706: warning: âtmpâ may be used uninitialized in this function
mv: cannot stat `/tmp/build/perf/util/.pmu.o.tmp': No such file or directory

This silences it, adding.

diff --git a/tools/perf/util/pmu.c b/tools/perf/util/pmu.c
index 913633ae0bf8..55f4de6442e3 100644
--- a/tools/perf/util/pmu.c
+++ b/tools/perf/util/pmu.c
@@ -703,7 +703,7 @@ struct pmu_events_map *perf_pmu__find_map(struct perf_pmu *pmu)

static bool pmu_uncore_alias_match(const char *pmu_name, const char *name)
{
- char *tmp, *tok, *str;
+ char *tmp = NULL, *tok, *str;
bool res;

str = strdup(pmu_name);


> + if (strncmp(pmu_name, tok, strlen(tok))) {
> + res = false;
> + goto out;
> + }
> +
> + /*
> + * Match more complex aliases where the alias name is a comma-delimited
> + * list of tokens, orderly contained in the matching PMU name.
> + *
> + * Example: For alias "socket,pmuname" and PMU "socketX_pmunameY", we
> + * match "socket" in "socketX_pmunameY" and then "pmuname" in
> + * "pmunameY".
> + */
> + for (; tok; name += strlen(tok), tok = strtok_r(NULL, ",", &tmp)) {
> + name = strstr(name, tok);
> + if (!name) {
> + res = false;
> + goto out;
> + }
> + }
> +
> + res = true;
> +out:
> + free(str);
> + return res;
> +}
> +
> /*
> * From the pmu_events_map, find the table of PMU events that corresponds
> * to the current running CPU. Then, add all PMU events from that table
> @@ -730,12 +770,8 @@ static void pmu_add_cpu_aliases(struct list_head *head, struct perf_pmu *pmu)
> break;
> }
>
> - /*
> - * uncore alias may be from different PMU
> - * with common prefix
> - */
> if (pmu_is_uncore(name) &&
> - !strncmp(pname, name, strlen(pname)))
> + pmu_uncore_alias_match(pname, name))
> goto new_alias;
>
> if (strcmp(pname, name))
> --
> 2.17.1

--

- Arnaldo