From: Frederic Weisbecker <[email protected]> commit 5225c45899e872383ca39f5533d28ec63c54b39e upstream.
Each histogram entry has a callchain root that stores the callchain samples. However we forgot to initialize the tracking of children hits of these roots, which then got random values on their creation. The root children hits is multiplied by the minimum percentage of hits provided by the user, and the result becomes the minimum hits expected from children branches. If the random value due to the uninitialization is big enough, then this minimum number of hits can be huge and eventually filter every children branches. The end result was invisible callchains. All we need to fix this is to initialize the children hits of the root. Reported-by: Christoph Hellwig <[email protected]> Signed-off-by: Frederic Weisbecker <[email protected]> Cc: Ingo Molnar <[email protected]> Cc: Peter Zijlstra <[email protected]> Cc: Arnaldo Carvalho de Melo <[email protected]> Cc: Paul Mackerras <[email protected]> Signed-off-by: Paul Gortmaker <[email protected]> --- tools/perf/util/callchain.h | 1 + 1 files changed, 1 insertions(+), 0 deletions(-) diff --git a/tools/perf/util/callchain.h b/tools/perf/util/callchain.h index 1b7a389..1121303 100644 --- a/tools/perf/util/callchain.h +++ b/tools/perf/util/callchain.h @@ -49,6 +49,7 @@ static inline void callchain_init(struct callchain_node *node) INIT_LIST_HEAD(&node->children); INIT_LIST_HEAD(&node->val); + node->children_hit = 0; node->parent = NULL; node->hit = 0; } -- 1.7.3.3 _______________________________________________ stable mailing list [email protected] http://linux.kernel.org/mailman/listinfo/stable
