examples: add cache effectiveness stats to gencache.stp

Signed-off-by: Ralph Boehme <[email protected]> Reviewed-by: Stefan Metzmacher <[email protected]> Autobuild-User(master): Ralph Böhme <[email protected]> Autobuild-Date(master): Fri Aug 11 14:19:24 CEST 2017 on sn-devel-144
Roo4L · Aug 11, 2017 · b2f2ce0 · b2f2ce0
1 parent 62925cf
commit b2f2ce0
Showing 1 changed file with 23 additions and 0 deletions.
diff --git a/examples/systemtap/gencache.stp b/examples/systemtap/gencache.stp
@@ -18,6 +18,7 @@
 #
 
 global running, intervals
+global cache_misses, cache_hits, neg_cache_hits
 
 probe begin {
 	printf("Collecting data, press ctrl-C to stop... ")
@@ -37,6 +38,18 @@ probe process(@1).library("*").function("gencache_parse").return {
 
 	duration = end - begin
 	intervals["gencache_parse"] <<< duration
+
+	if ($return == 0) {
+		cache_misses++
+	} else {
+		cache_hits++
+	}
+}
+
+probe process(@1).library("*").function("gencache_get_data_blob_parser") {
+	if ($timeout == 0) {
+		neg_cache_hits++
+	}
 }
 
 probe process(@1).library("*").function("gencache_get_data_blob") {
@@ -106,6 +119,16 @@ probe process(@1).library("*").function("gencache_stabilize").return {
 probe end {
 	printf("\n\n")
 
+	printf("Summary of cache access stats\n")
+	printf("=============================\n\n")
+	printf("%-10s %-10s %-10s\n",
+	       "Hits", "Misses", "Negative-Hits");
+	printf("--------------------------------------\n")
+	printf("%-10d %-10d %-10d\n",
+	       cache_hits, cache_misses, neg_cache_hits);
+
+	printf("\n")
+
 	foreach ([name] in intervals) {
 		printf("%-30s count: %d sum: %d us (min: %d us avg: %d us max: %d us)\n",
 		       name,