From f3058a1c1932aa1b027856945163144bda6366df Mon Sep 17 00:00:00 2001 From: Wang Nan Date: Tue, 24 May 2016 02:28:59 +0000 Subject: [PATCH] perf evlist: Don't poll and mmap overwritable events There's no need to receive events from overwritable ring buffer. Instead, perf should make them run in background until some external event of interest takes place. This patch makes ignores normal events from overwrite evlists. Overwritable events must be mapped readonly and backward, so if evlist and evsel doesn't match (evsel->overwrite is true but either evlist is read/write or evlist is not backward, and vice versa), skip mapping it. Signed-off-by: Wang Nan Cc: Jiri Olsa Cc: Masami Hiramatsu Cc: Namhyung Kim Cc: Zefan Li Cc: pi3orama@163.com Link: http://lkml.kernel.org/r/1464056944-166978-3-git-send-email-wangnan0@huawei.com Signed-off-by: He Kuang [ Split from a larger patch ] Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/util/evlist.c | 23 +++++++++++++++++++---- 1 file changed, 19 insertions(+), 4 deletions(-) diff --git a/tools/perf/util/evlist.c b/tools/perf/util/evlist.c index e82ba90..50d7b80 100644 --- a/tools/perf/util/evlist.c +++ b/tools/perf/util/evlist.c @@ -462,9 +462,9 @@ int perf_evlist__alloc_pollfd(struct perf_evlist *evlist) return 0; } -static int __perf_evlist__add_pollfd(struct perf_evlist *evlist, int fd, int idx) +static int __perf_evlist__add_pollfd(struct perf_evlist *evlist, int fd, int idx, short revent) { - int pos = fdarray__add(&evlist->pollfd, fd, POLLIN | POLLERR | POLLHUP); + int pos = fdarray__add(&evlist->pollfd, fd, revent | POLLERR | POLLHUP); /* * Save the idx so that when we filter out fds POLLHUP'ed we can * close the associated evlist->mmap[] entry. @@ -480,7 +480,7 @@ static int __perf_evlist__add_pollfd(struct perf_evlist *evlist, int fd, int idx int perf_evlist__add_pollfd(struct perf_evlist *evlist, int fd) { - return __perf_evlist__add_pollfd(evlist, fd, -1); + return __perf_evlist__add_pollfd(evlist, fd, -1, POLLIN); } static void perf_evlist__munmap_filtered(struct fdarray *fda, int fd) @@ -983,15 +983,28 @@ static int __perf_evlist__mmap(struct perf_evlist *evlist, int idx, return 0; } +static bool +perf_evlist__should_poll(struct perf_evlist *evlist __maybe_unused, + struct perf_evsel *evsel) +{ + if (evsel->overwrite) + return false; + return true; +} + static int perf_evlist__mmap_per_evsel(struct perf_evlist *evlist, int idx, struct mmap_params *mp, int cpu, int thread, int *output) { struct perf_evsel *evsel; + int revent; evlist__for_each(evlist, evsel) { int fd; + if (evsel->overwrite != (evlist->overwrite && evlist->backward)) + continue; + if (evsel->system_wide && thread) continue; @@ -1008,6 +1021,8 @@ static int perf_evlist__mmap_per_evsel(struct perf_evlist *evlist, int idx, perf_evlist__mmap_get(evlist, idx); } + revent = perf_evlist__should_poll(evlist, evsel) ? POLLIN : 0; + /* * The system_wide flag causes a selected event to be opened * always without a pid. Consequently it will never get a @@ -1016,7 +1031,7 @@ static int perf_evlist__mmap_per_evsel(struct perf_evlist *evlist, int idx, * Therefore don't add it for polling. */ if (!evsel->system_wide && - __perf_evlist__add_pollfd(evlist, fd, idx) < 0) { + __perf_evlist__add_pollfd(evlist, fd, idx, revent) < 0) { perf_evlist__mmap_put(evlist, idx); return -1; } -- 2.7.4