Re: [PATCH] perf: Add a new sort order: SORT_INCLUSIVE (v4)
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On 3/24/12 7:14 PM, Frederic Weisbecker wrote:
The other problem in branch stacks/LBR is that they're sampled branches. Just because I got a sample with: a -> b b -> c doesn't necessarily mean that the callchain was a -> b -> c.Not sure what you mean. If you have a -> b, b -> c in single LBR sample it means you got a -> b -> c.
I was going by Stephane's commit message here: http://article.gmane.org/gmane.linux.kernel/1236999 > Statistical sampling of taken branch should not be confused > for branch tracing. Not all branches are necessarily capturedStephane, could you please explain if the 16 filtered branches in LBR are guaranteed to be from a given callchain to the leaf function? My understanding is that it's not.
callchain1: a -> b -> d -> e (sample a->b) callchain2: a -> c -> b -> f (sample b->f) on PMU interrupt can we end up with: b -> f <- top of stack a -> b ... even though a -> b -> f can never happen in the actual program flow? -Arun -- To unsubscribe from this list: send the line "unsubscribe linux-perf-users" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html