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perf top: Add overwrite fall back 

Switch to non-overwrite mode if kernel doesnot support overwrite
ringbuffer.

It's only effect when overwrite mode is supported.  No change to current
behavior.

Signed-off-by: Kan Liang <kan.liang@intel.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Jin Yao <yao.jin@linux.intel.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/r/1516310792-208685-14-git-send-email-kan.liang@intel.com
[ Use perf_missing_features.write_backward instead of the non merged is_write_backward_fail() ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
hifive-unleashed-5.1
Kan Liang 2018-01-18 13:26:28 -08:00 committed by Arnaldo Carvalho de Melo
parent 9a831b3a32
commit 204721d7ea
1 changed files with 36 additions and 0 deletions
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36
tools/perf/builtin-top.c
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@ -943,6 +943,27 @@ static int perf_top__overwrite_check(struct perf_top *top)
return 0;
}
static int perf_top_overwrite_fallback(struct perf_top *top,
struct perf_evsel *evsel)
{
struct record_opts *opts = &top->record_opts;
struct perf_evlist *evlist = top->evlist;
struct perf_evsel *counter;
if (!opts->overwrite)
return 0;
/* only fall back when first event fails */
if (evsel != perf_evlist__first(evlist))
return 0;
evlist__for_each_entry(evlist, counter)
counter->attr.write_backward = false;
opts->overwrite = false;
ui__warning("fall back to non-overwrite mode\n");
return 1;
}
static int perf_top__start_counters(struct perf_top *top)
{
char msg[BUFSIZ];
@ -967,6 +988,21 @@ static int perf_top__start_counters(struct perf_top *top)
try_again:
if (perf_evsel__open(counter, top->evlist->cpus,
top->evlist->threads) < 0) {
/*
* Specially handle overwrite fall back.
* Because perf top is the only tool which has
* overwrite mode by default, support
* both overwrite and non-overwrite mode, and
* require consistent mode for all events.
*
* May move it to generic code with more tools
* have similar attribute.
*/
if (perf_missing_features.write_backward &&
perf_top_overwrite_fallback(top, counter))
goto try_again;
if (perf_evsel__fallback(counter, errno, msg, sizeof(msg))) {
if (verbose > 0)
ui__warning("%s\n", msg);