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authorFrederic Weisbecker <fweisbec@gmail.com>2011-01-14 06:51:58 +0300
committerArnaldo Carvalho de Melo <acme@redhat.com>2011-01-23 00:56:31 +0300
commit1b3a0e9592ebf174af934b3908a2bf6a6fa86169 (patch)
tree22de930ec03920ea7a4d602d9a582f5125595916 /tools/perf/util/hist.h
parentde5fa3a8a05cd60f59622e88cfeb90416760d78e (diff)
downloadlinux-1b3a0e9592ebf174af934b3908a2bf6a6fa86169.tar.xz
perf callchain: Feed callchains into a cursor
The callchains are fed with an array of a fixed size. As a result we iterate over each callchains three times: - 1st to resolve symbols - 2nd to filter out context boundaries - 3rd for the insertion into the tree This also involves some pairs of memory allocation/deallocation everytime we insert a callchain, for the filtered out array of addresses and for the array of symbols that comes along. Instead, feed the callchains through a linked list with persistent allocations. It brings several pros like: - Merge the 1st and 2nd iterations in one. That was possible before but in a way that would involve allocating an array slightly taller than necessary because we don't know in advance the number of context boundaries to filter out. - Much lesser allocations/deallocations. The linked list keeps persistent empty entries for the next usages and is extendable at will. - Makes it easier for multiple sources of callchains to feed a stacktrace together. This is deemed to pave the way for cfi based callchains wherein traditional frame pointer based kernel stacktraces will precede cfi based user ones, producing an overall callchain which size is hardly predictable. This requirement makes the static array obsolete and makes a linked list based iterator a much more flexible fit. Basic testing on a big perf file containing callchains (~ 176 MB) has shown a throughput gain of about 11% with perf report. Cc: Ingo Molnar <mingo@elte.hu> Cc: Paul Mackerras <paulus@samba.org> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <1294977121-5700-2-git-send-email-fweisbec@gmail.com> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Diffstat (limited to 'tools/perf/util/hist.h')
-rw-r--r--tools/perf/util/hist.h2
1 files changed, 2 insertions, 0 deletions
diff --git a/tools/perf/util/hist.h b/tools/perf/util/hist.h
index ee789856a8c9..889559b86492 100644
--- a/tools/perf/util/hist.h
+++ b/tools/perf/util/hist.h
@@ -77,6 +77,8 @@ struct hists {
u64 event_stream;
u32 type;
u16 col_len[HISTC_NR_COLS];
+ /* Best would be to reuse the session callchain cursor */
+ struct callchain_cursor callchain_cursor;
};
struct hist_entry *__hists__add_entry(struct hists *self,