Messages in this thread Patch in this message |  | | | From | Arnaldo Carvalho de Melo <> | | Subject | [PATCH 11/16] perf record: Fix fallback to cpu-clock on ppc | | Date | Thu, 10 May 2012 14:17:40 -0300 |
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From: David Ahern <dsahern@gmail.com>
perf-record on PPC is not falling back to cpu-clock:
$ perf record -ag -fo /tmp/perf.data -- sleep 1
Error: sys_perf_event_open() syscall returned with 6 (No such device or address). /bin/dmesg may provide additional information.
Fatal: No CONFIG_PERF_EVENTS=y kernel support configured?
The problem is that until 2.6.37 (behavior changed with commit b0a873e) perf on PPC returns ENXIO when hw_perf_event_init() fails. With this patch we get the expected behavior:
$ perf record -ag -fo /tmp/perf.data -v -- sleep 1 Old kernel, cannot exclude guest or host samples. The cycles event is not supported, trying to fall back to cpu-clock-ticks [ perf record: Woken up 1 times to write data ] [ perf record: Captured and wrote 0.151 MB /tmp/perf.data (~6592 samples) ]
Signed-off-by: David Ahern <dsahern@gmail.com> Cc: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/1336490937-57106-1-git-send-email-dsahern@gmail.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com> --- tools/perf/builtin-record.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c index 42e2414..1a9098c 100644 --- a/tools/perf/builtin-record.c +++ b/tools/perf/builtin-record.c @@ -242,9 +242,13 @@ try_again: /* * If it's cycles then fall back to hrtimer * based cpu-clock-tick sw counter, which - * is always available even if no PMU support: + * is always available even if no PMU support. + * + * PPC returns ENXIO until 2.6.37 (behavior changed + * with commit b0a873e). */ - if (err == ENOENT && attr->type == PERF_TYPE_HARDWARE + if ((err == ENOENT || err == ENXIO) + && attr->type == PERF_TYPE_HARDWARE && attr->config == PERF_COUNT_HW_CPU_CYCLES) { if (verbose) -- 1.7.9.2.358.g22243
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