Messages in this thread Patch in this message | | | From | Wang Nan <> | Subject | [PATCH 2/4] perf tools: Extract __perf_evlist__mmap_read() | Date | Thu, 7 Apr 2016 09:42:58 +0000 |
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Extract event reader to __perf_evlist__mmap_read(). Future commit will feed it with manually computed 'head' and 'old' pointers.
Signed-off-by: Wang Nan <wangnan0@huawei.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Zefan Li <lizefan@huawei.com> Cc: pi3orama@163.com --- tools/perf/util/evlist.c | 40 +++++++++++++++++++++++++--------------- 1 file changed, 25 insertions(+), 15 deletions(-)
diff --git a/tools/perf/util/evlist.c b/tools/perf/util/evlist.c index 692fd05..119bf27 100644 --- a/tools/perf/util/evlist.c +++ b/tools/perf/util/evlist.c @@ -679,24 +679,15 @@ static struct perf_evsel *perf_evlist__event2evsel(struct perf_evlist *evlist, return NULL; } -union perf_event *perf_evlist__mmap_read(struct perf_evlist *evlist, int idx) +static union perf_event * +__perf_evlist__mmap_read(struct perf_mmap *md, bool overwrite, u64 head, + u64 old, u64 *prev) { - struct perf_mmap *md = &evlist->mmap[idx]; - u64 head; - u64 old = md->prev; - int diff; unsigned char *data = md->base + page_size; union perf_event *event = NULL; + int diff = head - old; - /* - * Check if event was unmapped due to a POLLHUP/POLLERR. - */ - if (!atomic_read(&md->refcnt)) - return NULL; - - head = perf_mmap__read_head(md); - diff = head - old; - if (evlist->overwrite) { + if (overwrite) { /* * If we're further behind than half the buffer, there's a chance * the writer will bite our tail and mess up the samples under us. @@ -751,11 +742,30 @@ union perf_event *perf_evlist__mmap_read(struct perf_evlist *evlist, int idx) } broken_event: - md->prev = old; + if (prev) + *prev = old; return event; } +union perf_event *perf_evlist__mmap_read(struct perf_evlist *evlist, int idx) +{ + struct perf_mmap *md = &evlist->mmap[idx]; + u64 head; + u64 old = md->prev; + + /* + * Check if event was unmapped due to a POLLHUP/POLLERR. + */ + if (!atomic_read(&md->refcnt)) + return NULL; + + head = perf_mmap__read_head(md); + + return __perf_evlist__mmap_read(md, evlist->overwrite, head, + old, &md->prev); +} + static bool perf_mmap__empty(struct perf_mmap *md) { return perf_mmap__read_head(md) == md->prev && !md->auxtrace_mmap.base; -- 1.8.3.4
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