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| author | Dmitry Adamushko <dmitry.adamushko@gmail.com> | 2008-02-17 22:34:07 +0100 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2008-04-19 19:44:57 +0200 |
| commit | 19fb518c2a0c5d88ed22bba7083b7e7bc2a9c231 (patch) | |
| tree | 4233d31e9124110fe73aa83cb3ec4c390924d448 /kernel | |
| parent | 50df5d6aea6694ca481b8005900401e8c95c2603 (diff) | |
| download | lwn-19fb518c2a0c5d88ed22bba7083b7e7bc2a9c231.tar.gz lwn-19fb518c2a0c5d88ed22bba7083b7e7bc2a9c231.zip | |
latencytop: optimize LT_BACKTRACEDEPTH loops a bit
There is no need to loop any longer when 'same == 0'.
Signed-off-by: Dmitry Adamushko <dmitry.adamushko@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/latencytop.c | 27 |
1 files changed, 17 insertions, 10 deletions
diff --git a/kernel/latencytop.c b/kernel/latencytop.c index b4e3c85abe74..7c74dab0d21b 100644 --- a/kernel/latencytop.c +++ b/kernel/latencytop.c @@ -64,8 +64,8 @@ account_global_scheduler_latency(struct task_struct *tsk, struct latency_record return; for (i = 0; i < MAXLR; i++) { - int q; - int same = 1; + int q, same = 1; + /* Nothing stored: */ if (!latency_record[i].backtrace[0]) { if (firstnonnull > i) @@ -73,12 +73,15 @@ account_global_scheduler_latency(struct task_struct *tsk, struct latency_record continue; } for (q = 0 ; q < LT_BACKTRACEDEPTH ; q++) { - if (latency_record[i].backtrace[q] != - lat->backtrace[q]) + unsigned long record = lat->backtrace[q]; + + if (latency_record[i].backtrace[q] != record) { same = 0; - if (same && lat->backtrace[q] == 0) break; - if (same && lat->backtrace[q] == ULONG_MAX) + } + + /* 0 and ULONG_MAX entries mean end of backtrace: */ + if (record == 0 || record == ULONG_MAX) break; } if (same) { @@ -143,14 +146,18 @@ account_scheduler_latency(struct task_struct *tsk, int usecs, int inter) for (i = 0; i < LT_SAVECOUNT ; i++) { struct latency_record *mylat; int same = 1; + mylat = &tsk->latency_record[i]; for (q = 0 ; q < LT_BACKTRACEDEPTH ; q++) { - if (mylat->backtrace[q] != - lat.backtrace[q]) + unsigned long record = lat.backtrace[q]; + + if (mylat->backtrace[q] != record) { same = 0; - if (same && lat.backtrace[q] == 0) break; - if (same && lat.backtrace[q] == ULONG_MAX) + } + + /* 0 and ULONG_MAX entries mean end of backtrace: */ + if (record == 0 || record == ULONG_MAX) break; } if (same) { |