[tip:perf/core] perf pmu: Support more complex PMU event aliasing

[tip-bot for John Garry]

Commit-ID:  730670b1d108c4a8aa1924762738ca38593ee44c
Gitweb:     https://git.kernel.org/tip/730670b1d108c4a8aa1924762738ca38593ee44c
Author:     John Garry <john.garry@xxxxxxxxxx>
AuthorDate: Fri, 28 Jun 2019 22:35:49 +0800
Committer:  Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
CommitDate: Tue, 2 Jul 2019 16:07:36 -0300

perf pmu: Support more complex PMU event aliasing

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>
Acked-by: Jiri Olsa <jolsa@xxxxxxxxxx>
Cc: Alexander Shishkin <alexander.shishkin@xxxxxxxxxxxxxxx>
Cc: Andi Kleen <ak@xxxxxxxxxxxxxxx>
Cc: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
Cc: Hendrik Brueckner <brueckner@xxxxxxxxxxxxx>
Cc: Kan Liang <kan.liang@xxxxxxxxxxxxxxx>
Cc: Mark Rutland <mark.rutland@xxxxxxx>
Cc: Mathieu Poirier <mathieu.poirier@xxxxxxxxxx>
Cc: Namhyung Kim <namhyung@xxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Shaokun Zhang <zhangshaokun@xxxxxxxxxxxxx>
Cc: Thomas Richter <tmricht@xxxxxxxxxxxxx>
Cc: Will Deacon <will.deacon@xxxxxxx>
Cc: linux-arm-kernel@xxxxxxxxxxxxxxxxxxx
Cc: linuxarm@xxxxxxxxxx
Link: http://lkml.kernel.org/r/1561732552-143038-2-git-send-email-john.garry@xxxxxxxxxx
[ Shut up older gcc complianing about the last arg to strtok_r() being uninitialized, set that tmp to NULL ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@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 8139a1f3ed39..55f4de6442e3 100644
--- a/tools/perf/util/pmu.c
+++ b/tools/perf/util/pmu.c
@@ -701,6 +701,46 @@ 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 = NULL, *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);
+	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
@@ -731,12 +771,8 @@ 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))