diff options
| author | Arnaldo Carvalho de Melo <acme@kernel.org> | 2016-06-20 10:47:18 +0000 |
|---|---|---|
| committer | Arnaldo Carvalho de Melo <acme@redhat.com> | 2016-06-21 13:18:35 -0300 |
| commit | 7da36e94e7fad768ca8640b61ed1f49b284e1dc5 (patch) | |
| tree | bb469c4e412e72259e460da85533b7595f9ca5d4 /tools | |
| parent | 0aab21363ffa66d6e7340bc50cc5bfae865fd1a6 (diff) | |
perf evsel: Fix write_backwards fallback
Commit b90dc17a5d14 "perf evsel: Add overwrite attribute and check
write_backward" misunderstood the 'order' should be obeyed in
__perf_evsel__open.
But the way this was done for attr.write_backwards was buggy, as we need
to check features in the inverse order of their introduction to the
kernel, so that a newer tool checks first the newest perf_event_attr
fields, detecting that the older kernel doesn't have support for them.
Also, we can avoid calling sys_perf_event_open() if we have already
detected the missing of write_backward.
Cc: He Kuang <hekuang@huawei.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Zefan Li <lizefan@huawei.com>
Cc: pi3orama@163.com
Fixes: b90dc17a5d14 ("perf evsel: Add overwrite attribute and check write_backward")
Link: http://lkml.kernel.org/r/1466419645-75551-2-git-send-email-wangnan0@huawei.com
Link: http://lkml.kernel.org/r/20160616214724.GI13337@kernel.org
Signed-off-by: Wang Nan <wangnan0@huawei.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Diffstat (limited to 'tools')
| -rw-r--r-- | tools/perf/util/evsel.c | 23 |
1 files changed, 10 insertions, 13 deletions
diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c index 9b2e3e624efe..1d8f2bbd38a7 100644 --- a/tools/perf/util/evsel.c +++ b/tools/perf/util/evsel.c @@ -1389,8 +1389,11 @@ fallback_missing_features: if (perf_missing_features.lbr_flags) evsel->attr.branch_sample_type &= ~(PERF_SAMPLE_BRANCH_NO_FLAGS | PERF_SAMPLE_BRANCH_NO_CYCLES); - if (perf_missing_features.write_backward) + if (perf_missing_features.write_backward) { + if (evsel->overwrite) + return -EINVAL; evsel->attr.write_backward = false; + } retry_sample_id: if (perf_missing_features.sample_id_all) evsel->attr.sample_id_all = 0; @@ -1453,12 +1456,6 @@ retry_open: err = -EINVAL; goto out_close; } - - if (evsel->overwrite && - perf_missing_features.write_backward) { - err = -EINVAL; - goto out_close; - } } } @@ -1496,7 +1493,10 @@ try_fallback: * Must probe features in the order they were added to the * perf_event_attr interface. */ - if (!perf_missing_features.clockid_wrong && evsel->attr.use_clockid) { + if (!perf_missing_features.write_backward && evsel->attr.write_backward) { + perf_missing_features.write_backward = true; + goto fallback_missing_features; + } else if (!perf_missing_features.clockid_wrong && evsel->attr.use_clockid) { perf_missing_features.clockid_wrong = true; goto fallback_missing_features; } else if (!perf_missing_features.clockid && evsel->attr.use_clockid) { @@ -1521,12 +1521,7 @@ try_fallback: PERF_SAMPLE_BRANCH_NO_FLAGS))) { perf_missing_features.lbr_flags = true; goto fallback_missing_features; - } else if (!perf_missing_features.write_backward && - evsel->attr.write_backward) { - perf_missing_features.write_backward = true; - goto fallback_missing_features; } - out_close: do { while (--thread >= 0) { @@ -2409,6 +2404,8 @@ int perf_evsel__open_strerror(struct perf_evsel *evsel, struct target *target, "We found oprofile daemon running, please stop it and try again."); break; case EINVAL: + if (evsel->overwrite && perf_missing_features.write_backward) + return scnprintf(msg, size, "Reading from overwrite event is not supported by this kernel."); if (perf_missing_features.clockid) return scnprintf(msg, size, "clockid feature not supported."); if (perf_missing_features.clockid_wrong) |