From 028d455b12719a48b1c4b51ce07a074135726f8f Mon Sep 17 00:00:00 2001 From: David Ahern Date: Tue, 8 May 2012 09:28:57 -0600 Subject: [PATCH] perf record: Fix fallback to cpu-clock on ppc 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 Cc: Peter Zijlstra Link: http://lkml.kernel.org/r/1336490937-57106-1-git-send-email-dsahern@gmail.com Signed-off-by: Arnaldo Carvalho de Melo --- 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 42e24149c791..1a9098c697b4 100644 --- a/tools/perf/builtin-record.c +++ b/tools/perf/builtin-record.c @@ -242,9 +242,13 @@ static void perf_record__open(struct perf_record *rec) /* * 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)