perf mmap: Introduce perf_mmap__read_event() (7bb45972) · Commits · 戴 / test

Except for 'perf record', the other perf tools read events one by one from the ring buffer using perf_mmap__read_forward(). But it only supports non-overwrite mode. Introduce perf_mmap__read_event() to support both non-overwrite and overwrite mode. Usage: perf_mmap__read_init() while(event = perf_mmap__read_event()) { //process the event perf_mmap__consume() } perf_mmap__read_done() It cannot use perf_mmap__read_backward(). Because it always reads the stale buffer which is already processed. Furthermore, the forward and backward concepts have been removed. The perf_mmap__read_backward() will be replaced and discarded later. Signed-off-by:

Kan Liang <kan.liang@intel.com> Acked-by:

Jiri Olsa <jolsa@kernel.org> Cc: Andi Kleen <ak@linux.intel.com> Cc: Jin Yao <yao.jin@linux.intel.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Wang Nan <wangnan0@huawei.com> Link: http://lkml.kernel.org/r/1516310792-208685-9-git-send-email-kan.liang@intel.com Signed-off-by:

Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/util/mmap.c

+39 −0

Original line number	Diff line number	Diff line
		@@ -113,6 +113,45 @@ union perf_event perf_mmap__read_backward(struct perf_mmap map)
		return perf_mmap__read(map, &map->prev, end);
		}

		/*
		* Read event from ring buffer one by one.
		* Return one event for each call.
		*
		* Usage:
		* perf_mmap__read_init()
		* while(event = perf_mmap__read_event()) {
		* //process the event
		* perf_mmap__consume()
		* }
		* perf_mmap__read_done()
		*/
		union perf_event perf_mmap__read_event(struct perf_mmap map,
		bool overwrite,
		u64 *startp, u64 end)
		{
		union perf_event *event;

		/*
		* Check if event was unmapped due to a POLLHUP/POLLERR.
		*/
		if (!refcount_read(&map->refcnt))
		return NULL;

		if (startp == NULL)
		return NULL;

		/* non-overwirte doesn't pause the ringbuffer */
		if (!overwrite)
		end = perf_mmap__read_head(map);

		event = perf_mmap__read(map, startp, end);

		if (!overwrite)
		map->prev = *startp;

		return event;
		}

		void perf_mmap__read_catchup(struct perf_mmap *map)
		{
		u64 head;

tools/perf/util/mmap.h

+4 −0

Original line number	Diff line number	Diff line
		@@ -89,6 +89,10 @@ static inline void perf_mmap__write_tail(struct perf_mmap *md, u64 tail)
		union perf_event perf_mmap__read_forward(struct perf_mmap map);
		union perf_event perf_mmap__read_backward(struct perf_mmap map);

		union perf_event perf_mmap__read_event(struct perf_mmap map,
		bool overwrite,
		u64 *startp, u64 end);

		int perf_mmap__push(struct perf_mmap *md, bool backward,
		void to, int push(void to, void *buf, size_t size));

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