[PATCH 2/5] perf pmu: Support more complex PMU event aliasing

[John Garry]

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 the 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 | 45 ++++++++++++++++++++++++++++++++++++++-----
 1 file changed, 40 insertions(+), 5 deletions(-)

diff --git a/tools/perf/util/pmu.c b/tools/perf/util/pmu.c
index 036047f56efa..f00cae750086 100644
--- a/tools/perf/util/pmu.c
+++ b/tools/perf/util/pmu.c
@@ -700,6 +700,44 @@ 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)
+{
+	/*
+	 * uncore alias may be from different PMU
+	 * with common prefix
+	 */
+	if (!strncmp(pmu_name, name, strlen(pmu_name)))
+		return true;
+
+	/* match strings with delimiter, ',' */
+	while (1) {
+		const char *delimiter;
+		char token[256] = {};
+		const char *found_token;
+		int token_len;
+
+		delimiter = strchr(pmu_name, ',');
+		if (delimiter) {
+			token_len = delimiter - pmu_name;
+		} else {
+			token_len = strlen(pmu_name);
+		}
+
+		memcpy(token, pmu_name, token_len);
+
+		found_token = strstr(name, token);
+		if (!found_token)
+			return false;
+
+		/* No more delimiters, so we must be a match */
+		if (!delimiter)
+			return true;
+
+		pmu_name += token_len + 1;
+		name = found_token + token_len;
+	}
+}
+
 /*
  * 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 +768,9 @@ 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