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Groups > linux.kernel > #1400568

[PATCH 08/17] perf record: Don't poll on overwrite channel

From Wang Nan <wangnan0@huawei.com>
Newsgroups linux.kernel
Subject [PATCH 08/17] perf record: Don't poll on overwrite channel
Date 2016-05-13 10:00 +0200
Message-ID <rygaS-7tc-29@gated-at.bofh.it> (permalink)
References <rygaR-7tc-1@gated-at.bofh.it>
Organization linux.* mail to news gateway

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There's no need to receive events from overwritable ring buffer. Instead,
perf should make them run background until something happen. This patch
makes normal events from overwrite ring buffer ignored.

Signed-off-by: Wang Nan <wangnan0@huawei.com>
Signed-off-by: He Kuang <hekuang@huawei.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Zefan Li <lizefan@huawei.com>
Cc: pi3orama@163.com
---
 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 abce588..f0b0457 100644
--- a/tools/perf/util/evlist.c
+++ b/tools/perf/util/evlist.c
@@ -461,9 +461,9 @@ 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.
@@ -479,7 +479,7 @@ 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)
@@ -1077,6 +1077,18 @@ perf_evlist__channel_complete(struct perf_evlist *evlist)
 	return 0;
 }
 
+static bool
+perf_evlist__should_poll(struct perf_evlist *evlist,
+			 struct perf_evsel *evsel,
+			 int channel)
+{
+	if (evsel->system_wide)
+		return false;
+	if (perf_evlist__channel_check(evlist, channel, RDONLY))
+		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 *outputs)
@@ -1085,6 +1097,7 @@ static int perf_evlist__mmap_per_evsel(struct perf_evlist *evlist, int _idx,
 
 	evlist__for_each(evlist, evsel) {
 		int fd, channel, idx, err;
+		short revent = POLLIN;
 
 		channel = perf_evlist__channel_find(evlist, evsel, false);
 		if (channel < 0) {
@@ -1114,6 +1127,8 @@ static int perf_evlist__mmap_per_evsel(struct perf_evlist *evlist, int _idx,
 			perf_evlist__mmap_get(evlist, idx);
 		}
 
+		if (!perf_evlist__should_poll(evlist, evsel, channel))
+			revent = 0;
 		/*
 		 * The system_wide flag causes a selected event to be opened
 		 * always without a pid.  Consequently it will never get a
@@ -1122,7 +1137,7 @@ 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;
 		}
-- 
1.8.3.4

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Thread

[PATCH 00/17] perf tools: Support overwritable ring buffer Wang Nan <wangnan0@huawei.com> - 2016-05-13 10:00 +0200
  [PATCH 15/17] perf record: Read from backward ring buffer Wang Nan <wangnan0@huawei.com> - 2016-05-13 10:00 +0200
  [PATCH 01/17] perf tools: Extract __perf_evlist__mmap_read() Wang Nan <wangnan0@huawei.com> - 2016-05-13 10:00 +0200
    Re: [PATCH 01/17] perf tools: Extract __perf_evlist__mmap_read() Arnaldo Carvalho de Melo <acme@kernel.org> - 2016-05-13 15:10 +0200
  [PATCH 09/17] perf tools: Detect avalibility of write_backward Wang Nan <wangnan0@huawei.com> - 2016-05-13 10:00 +0200
    Re: [PATCH 09/17] perf tools: Detect avalibility of write_backward Arnaldo Carvalho de Melo <acme@kernel.org> - 2016-05-13 15:10 +0200
      Re: [PATCH 09/17] perf tools: Detect avalibility of write_backward "Wangnan (F)" <wangnan0@huawei.com> - 2016-05-20 17:40 +0200
        Re: [PATCH 09/17] perf tools: Detect avalibility of write_backward Arnaldo Carvalho de Melo <acme@kernel.org> - 2016-05-20 17:40 +0200
  [PATCH 05/17] perf record: Prevent reading invalid data in record__mmap_read Wang Nan <wangnan0@huawei.com> - 2016-05-13 10:00 +0200
  [PATCH 17/17] perf tools: Don't warn about out of order event if write_backward is used Wang Nan <wangnan0@huawei.com> - 2016-05-13 10:00 +0200
  [PATCH 11/17] perf tools: Set write_backward attribut bit for overwrite events Wang Nan <wangnan0@huawei.com> - 2016-05-13 10:00 +0200
  [PATCH 04/17] perf tools: Operate multiple channels Wang Nan <wangnan0@huawei.com> - 2016-05-13 10:00 +0200
  [PATCH 08/17] perf record: Don't poll on overwrite channel Wang Nan <wangnan0@huawei.com> - 2016-05-13 10:00 +0200
    Re: [PATCH 08/17] perf record: Don't poll on overwrite channel Arnaldo Carvalho de Melo <acme@kernel.org> - 2016-05-13 15:20 +0200
      Re: [PATCH 08/17] perf record: Don't poll on overwrite channel "Wangnan (F)" <wangnan0@huawei.com> - 2016-05-16 05:20 +0200
  [PATCH 16/17] perf record: Toggle overwrite ring buffer for reading Wang Nan <wangnan0@huawei.com> - 2016-05-13 10:00 +0200
  [PATCH 10/17] perf tools: Enable overwrite settings Wang Nan <wangnan0@huawei.com> - 2016-05-13 10:00 +0200
    Re: [PATCH 10/17] perf tools: Enable overwrite settings Arnaldo Carvalho de Melo <acme@kernel.org> - 2016-05-16 15:40 +0200
  [PATCH 07/17] perf record: Don't read from and poll overwrite channel Wang Nan <wangnan0@huawei.com> - 2016-05-13 10:00 +0200
  [PATCH 12/17] perf tools: Record fd into perf_mmap Wang Nan <wangnan0@huawei.com> - 2016-05-13 10:00 +0200
  [PATCH 13/17] perf tools: Add API to pause a channel Wang Nan <wangnan0@huawei.com> - 2016-05-13 10:00 +0200
  [PATCH 14/17] perf record: Rename variable to make code clear Wang Nan <wangnan0@huawei.com> - 2016-05-13 10:10 +0200
  [PATCH 02/17] perf tools: Add evlist channel helpers Wang Nan <wangnan0@huawei.com> - 2016-05-13 10:10 +0200
    Re: [PATCH 02/17] perf tools: Add evlist channel helpers Arnaldo Carvalho de Melo <acme@kernel.org> - 2016-05-13 15:10 +0200
      Re: [PATCH 02/17] perf tools: Add evlist channel helpers "Wangnan (F)" <wangnan0@huawei.com> - 2016-05-18 05:40 +0200
        Re: [PATCH 02/17] perf tools: Add evlist channel helpers Arnaldo Carvalho de Melo <arnaldo.melo@gmail.com> - 2016-05-18 15:30 +0200
  [PATCH 03/17] perf tools: Automatically add new channel according to evlist Wang Nan <wangnan0@huawei.com> - 2016-05-13 10:20 +0200
  [PATCH 06/17] perf tools: Squash overwrite setting into channel Wang Nan <wangnan0@huawei.com> - 2016-05-13 10:20 +0200

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