perf streams: Compare two streams

Stream is the branch history which is aggregated by the branch records
from perf samples. Now we support the callchain as stream.

If the callchain entries of one stream are fully matched with the
callchain entries of another stream, we think two streams are matched.

For example,

   cycles: 1, hits: 26.80%                 cycles: 1, hits: 27.30%
   -----------------------                 -----------------------
             main div.c:39                           main div.c:39
             main div.c:44                           main div.c:44

Above two streams are matched (we don't consider the case that source
code is changed).

The matching logic is, compare the chain string first. If it's not
matched, fallback to dso address comparison.

Signed-off-by: Jin Yao <yao.jin@linux.intel.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Link: https://lore.kernel.org/r/20201009022845.13141-4-yao.jin@linux.intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

1 files changed, 4 insertions, 0 deletions

diff --git a/tools/perf/util/callchain.h b/tools/perf/util/callchain.h
index fe36a9e5ccd1..ad27fc8c7948 100644
--- a/tools/perf/util/callchain.h
+++ b/tools/perf/util/callchain.h
@@ -298,4 +298,8 @@ int callchain_branch_counts(struct callchain_root *root,
 			    u64 *abort_count, u64 *cycles_count);
 
 void callchain_param_setup(u64 sample_type);
+
+bool callchain_cnode_matched(struct callchain_node *base_cnode,
+			     struct callchain_node *pair_cnode);
+
 #endif	/* __PERF_CALLCHAIN_H */