Commit-ID: 2305c82fb35dd2c8c9533303bb1693f1636c66e4
Gitweb: http://git.kernel.org/tip/2305c82fb35dd2c8c9533303bb1693f1636c66e4
Author: David Ahern <dsahern@xxxxxxxxx>
AuthorDate: Thu, 13 Sep 2012 14:59:15 -0600
Committer: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
CommitDate: Wed, 24 Oct 2012 14:20:11 -0200
perf tools: Give user better message if precise is not supported
Platforms (e.g., VM's) without support for precise mode get a confusing
error message. e.g.,
$ perf record -e cycles:p -a -- sleep 1
Error: sys_perf_event_open() syscall returned with 95 (Operation not
supported). /bin/dmesg may provide additional information.
No hardware sampling interrupt available. No APIC? If so then you can
boot the kernel with the "lapic" boot parameter to force-enable it.
sleep: Terminated
which is not clear that precise mode might be the root problem. With this
patch:
$ perf record -e cycles:p -fo /tmp/perf.data -- sleep 1
Error:
'precise' request may not be supported. Try removing 'p' modifier
sleep: Terminated
v2: softened message to 'may not be' supported per Robert's suggestion
Signed-off-by: David Ahern <dsahern@xxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Robert Richter <robert.richter@xxxxxxx>
Link: http://lkml.kernel.org/r/1347569955-54626-4-git-send-email-dsahern@xxxxxxxxx
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
---
tools/perf/builtin-record.c | 5 +++++
tools/perf/builtin-top.c | 4 ++++
2 files changed, 9 insertions(+), 0 deletions(-)
diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
index 73b5d7f..53c9892 100644
--- a/tools/perf/builtin-record.c
+++ b/tools/perf/builtin-record.c
@@ -317,6 +317,11 @@ try_again:
perf_evsel__name(pos));
rc = -err;
goto out;
+ } else if ((err == EOPNOTSUPP) && (attr->precise_ip)) {
+ ui__error("\'precise\' request may not be supported. "
+ "Try removing 'p' modifier\n");
+ rc = -err;
+ goto out;
}
printf("\n");
diff --git a/tools/perf/builtin-top.c b/tools/perf/builtin-top.c
index fb9da71..f2ecd49 100644
--- a/tools/perf/builtin-top.c
+++ b/tools/perf/builtin-top.c
@@ -977,6 +977,10 @@ try_again:
ui__error("Too many events are opened.\n"
"Try again after reducing the number of events\n");
goto out_err;
+ } else if ((err == EOPNOTSUPP) && (attr->precise_ip)) {
+ ui__error("\'precise\' request may not be supported. "
+ "Try removing 'p' modifier\n");
+ goto out_err;
}
ui__error("The sys_perf_event_open() syscall "
--
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