On 2016/5/13 21:12, Arnaldo Carvalho de Melo wrote:
Em Fri, May 13, 2016 at 07:56:05AM +0000, Wang Nan escreveu:
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 <[email protected]>
Signed-off-by: He Kuang <[email protected]>
Cc: Arnaldo Carvalho de Melo <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Masami Hiramatsu <[email protected]>
Cc: Namhyung Kim <[email protected]>
Cc: Zefan Li <[email protected]>
Cc: [email protected]
---
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;
So, what is the above doing in this patch? If we should not poll when in
syswide mode, then this should be in a separate patch, unrelated to
'channels'. No?
I think the name 'system_wide' is more or less missleading. It is not means
an event in 'perf record -a', but means "a selected event to be opened
always
without a pid when configured by perf_evsel__config().". See bf8e8f4b8.
Here we use similary logic in existing perf_evlist__mmap_per_evsel. It never
poll system_wide evsel:
/*
* The system_wide flag causes a selected event to be
opened
* always without a pid. Consequently it will never get a
* POLLHUP, but it is used for tracking in combination with
* other events, so it should not need to be polled anyway.
* Therefore don't add it for polling.
*/
if (!evsel->system_wide &&
__perf_evlist__add_pollfd(evlist, fd, idx) < 0) {
perf_evlist__mmap_put(evlist, idx);
return -1;
}
Thank you.
