perf auxtrace: Add a hashtable for caching

Decoding AUX area data may involve walking object code.  Rather than
repetitively decoding the same instructions, a cache can be used to
cache the results.

This patch implements a fairly generic hashtable with a 32-bit key that
could be used for other purposes as well.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/r/1428594864-29309-15-git-send-email-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

1 files changed, 14 insertions, 0 deletions

diff --git a/tools/perf/util/auxtrace.h b/tools/perf/util/auxtrace.h
index ba78d825bf73..53b60a64a693 100644
--- a/tools/perf/util/auxtrace.h
+++ b/tools/perf/util/auxtrace.h
@@ -333,6 +333,20 @@ int auxtrace_heap__add(struct auxtrace_heap *heap, unsigned int queue_nr,
 void auxtrace_heap__pop(struct auxtrace_heap *heap);
 void auxtrace_heap__free(struct auxtrace_heap *heap);
 
+struct auxtrace_cache_entry {
+        struct hlist_node hash;
+        u32 key;
+};
+
+struct auxtrace_cache *auxtrace_cache__new(unsigned int bits, size_t entry_size,
+                                           unsigned int limit_percent);
+void auxtrace_cache__free(struct auxtrace_cache *auxtrace_cache);
+void *auxtrace_cache__alloc_entry(struct auxtrace_cache *c);
+void auxtrace_cache__free_entry(struct auxtrace_cache *c, void *entry);
+int auxtrace_cache__add(struct auxtrace_cache *c, u32 key,
+                        struct auxtrace_cache_entry *entry);
+void *auxtrace_cache__lookup(struct auxtrace_cache *c, u32 key);
+
 struct auxtrace_record *auxtrace_record__init(struct perf_evlist *evlist,
                                               int *err);