From: Arnaldo Carvalho de Melo <a...@redhat.com> evsel->overwrite indicator means an event should be put into overwritable ring buffer. In current implementation, it equals to evsel->attr.write_backward. To reduce compliexity, remove evsel->overwrite, use evsel->attr.write_backward instead.
In addition, in __perf_evsel__open(), if kernel doesn't support write_backward and user explicitly set it in evsel, don't fallback like other missing feature, since it is meaningless to fall back to a forward ring buffer in this case: we are unable to stably read from an forward overwritable ring buffer. Signed-off-by: Arnaldo Carvalho de Melo <a...@redhat.com> Signed-off-by: Wang Nan <wangn...@huawei.com> Cc: He Kuang <heku...@huawei.com> Cc: Jiri Olsa <jo...@kernel.org> Cc: Masami Hiramatsu <mhira...@kernel.org> Cc: Namhyung Kim <namhy...@kernel.org> Cc: Zefan Li <lize...@huawei.com> Cc: Nilay Vaish <nilayva...@gmail.com> Cc: pi3or...@163.com --- tools/perf/tests/backward-ring-buffer.c | 1 + tools/perf/util/evlist.c | 4 ++-- tools/perf/util/evsel.c | 12 +++++------- tools/perf/util/evsel.h | 1 - 4 files changed, 8 insertions(+), 10 deletions(-) diff --git a/tools/perf/tests/backward-ring-buffer.c b/tools/perf/tests/backward-ring-buffer.c index e70313f..1750ef2 100644 --- a/tools/perf/tests/backward-ring-buffer.c +++ b/tools/perf/tests/backward-ring-buffer.c @@ -101,6 +101,7 @@ int test__backward_ring_buffer(int subtest __maybe_unused) return TEST_FAIL; } + evlist->backward = true; err = perf_evlist__create_maps(evlist, &opts.target); if (err < 0) { pr_debug("Not enough memory to create thread/cpu maps\n"); diff --git a/tools/perf/util/evlist.c b/tools/perf/util/evlist.c index 1135077..7228596 100644 --- a/tools/perf/util/evlist.c +++ b/tools/perf/util/evlist.c @@ -1003,7 +1003,7 @@ static bool perf_evlist__should_poll(struct perf_evlist *evlist __maybe_unused, struct perf_evsel *evsel) { - if (evsel->overwrite) + if (evsel->attr.write_backward) return false; return true; } @@ -1018,7 +1018,7 @@ static int perf_evlist__mmap_per_evsel(struct perf_evlist *evlist, int idx, evlist__for_each_entry(evlist, evsel) { int fd; - if (evsel->overwrite != (evlist->overwrite && evlist->backward)) + if (!!evsel->attr.write_backward != (evlist->overwrite && evlist->backward)) continue; if (evsel->system_wide && thread) diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c index 0fea724..3abe519 100644 --- a/tools/perf/util/evsel.c +++ b/tools/perf/util/evsel.c @@ -1359,6 +1359,9 @@ static int __perf_evsel__open(struct perf_evsel *evsel, struct cpu_map *cpus, int pid = -1, err; enum { NO_CHANGE, SET_TO_MAX, INCREASED_MAX } set_rlimit = NO_CHANGE; + if (perf_missing_features.write_backward && evsel->attr.write_backward) + return -EINVAL; + if (evsel->system_wide) nthreads = 1; else @@ -1389,11 +1392,6 @@ 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 (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; @@ -1495,7 +1493,7 @@ try_fallback: */ if (!perf_missing_features.write_backward && evsel->attr.write_backward) { perf_missing_features.write_backward = true; - goto fallback_missing_features; + goto out_close; } else if (!perf_missing_features.clockid_wrong && evsel->attr.use_clockid) { perf_missing_features.clockid_wrong = true; goto fallback_missing_features; @@ -2404,7 +2402,7 @@ 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) + if (evsel->attr.write_backward && 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."); diff --git a/tools/perf/util/evsel.h b/tools/perf/util/evsel.h index 86fed7a..a31ee2d 100644 --- a/tools/perf/util/evsel.h +++ b/tools/perf/util/evsel.h @@ -114,7 +114,6 @@ struct perf_evsel { bool tracking; bool per_pkg; bool precise_max; - bool overwrite; /* parse modifier helper */ int exclude_GH; int nr_members; -- 1.8.3.4