From ca6a9a05391960be5e8161a59a9854b32325d901 Mon Sep 17 00:00:00 2001 From: Wang Nan Date: Sun, 3 Dec 2017 02:00:40 +0000 Subject: perf mmap: Remove overwrite from arguments list of perf_mmap__push 'overwrite' argument is always 'false'. Remove it from arguments list of perf_mmap__push(). Signed-off-by: Wang Nan Acked-by: Namhyung Kim Cc: Jiri Olsa Cc: Kan Liang Link: http://lkml.kernel.org/r/20171203020044.81680-5-wangnan0@huawei.com Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/util/mmap.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) (limited to 'tools/perf/util/mmap.c') diff --git a/tools/perf/util/mmap.c b/tools/perf/util/mmap.c index 9fe5f9c7d577..703ed41a9269 100644 --- a/tools/perf/util/mmap.c +++ b/tools/perf/util/mmap.c @@ -299,7 +299,7 @@ static int rb_find_range(void *data, int mask, u64 head, u64 old, return backward_rb_find_range(data, mask, head, start, end); } -int perf_mmap__push(struct perf_mmap *md, bool overwrite, bool backward, +int perf_mmap__push(struct perf_mmap *md, bool backward, void *to, int push(void *to, void *buf, size_t size)) { u64 head = perf_mmap__read_head(md); @@ -321,7 +321,7 @@ int perf_mmap__push(struct perf_mmap *md, bool overwrite, bool backward, WARN_ONCE(1, "failed to keep up with mmap data. (warn only once)\n"); md->prev = head; - perf_mmap__consume(md, overwrite || backward); + perf_mmap__consume(md, backward); return 0; } @@ -346,7 +346,7 @@ int perf_mmap__push(struct perf_mmap *md, bool overwrite, bool backward, } md->prev = head; - perf_mmap__consume(md, overwrite || backward); + perf_mmap__consume(md, backward); out: return rc; } -- cgit v1.2.3 From 8eb7a1fe31612fd3e8ae8042dd2ebaf7575504cb Mon Sep 17 00:00:00 2001 From: Wang Nan Date: Sun, 3 Dec 2017 02:00:41 +0000 Subject: perf mmap: Remove overwrite and check_messup from mmap read All perf_mmap__read_forward() read from read-write ring buffer, so no need check_messup. Reading from backward ring buffer doesn't require check_messup because it never mess up. Cleanup arguments lists. Signed-off-by: Wang Nan Acked-by: Namhyung Kim Cc: Jiri Olsa Cc: Kan Liang Link: http://lkml.kernel.org/r/20171203020044.81680-6-wangnan0@huawei.com Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/util/mmap.c | 28 ++++------------------------ 1 file changed, 4 insertions(+), 24 deletions(-) (limited to 'tools/perf/util/mmap.c') diff --git a/tools/perf/util/mmap.c b/tools/perf/util/mmap.c index 703ed41a9269..3f262e707a41 100644 --- a/tools/perf/util/mmap.c +++ b/tools/perf/util/mmap.c @@ -21,33 +21,13 @@ size_t perf_mmap__mmap_len(struct perf_mmap *map) } /* When check_messup is true, 'end' must points to a good entry */ -static union perf_event *perf_mmap__read(struct perf_mmap *map, bool check_messup, +static union perf_event *perf_mmap__read(struct perf_mmap *map, u64 start, u64 end, u64 *prev) { unsigned char *data = map->base + page_size; union perf_event *event = NULL; int diff = end - start; - if (check_messup) { - /* - * 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. - * - * If we somehow ended up ahead of the 'end', we got messed up. - * - * In either case, truncate and restart at 'end'. - */ - if (diff > map->mask / 2 || diff < 0) { - fprintf(stderr, "WARNING: failed to keep up with mmap data.\n"); - - /* - * 'end' points to a known good entry, start there. - */ - start = end; - diff = 0; - } - } - if (diff >= (int)sizeof(event->header)) { size_t size; @@ -89,7 +69,7 @@ broken_event: return event; } -union perf_event *perf_mmap__read_forward(struct perf_mmap *map, bool check_messup) +union perf_event *perf_mmap__read_forward(struct perf_mmap *map) { u64 head; u64 old = map->prev; @@ -102,7 +82,7 @@ union perf_event *perf_mmap__read_forward(struct perf_mmap *map, bool check_mess head = perf_mmap__read_head(map); - return perf_mmap__read(map, check_messup, old, head, &map->prev); + return perf_mmap__read(map, old, head, &map->prev); } union perf_event *perf_mmap__read_backward(struct perf_mmap *map) @@ -138,7 +118,7 @@ union perf_event *perf_mmap__read_backward(struct perf_mmap *map) else end = head + map->mask + 1; - return perf_mmap__read(map, false, start, end, &map->prev); + return perf_mmap__read(map, start, end, &map->prev); } void perf_mmap__read_catchup(struct perf_mmap *map) -- cgit v1.2.3 From 7fb4b407a1242dbc85ea3ed1be065dca8f9a6f5b Mon Sep 17 00:00:00 2001 From: Wang Nan Date: Mon, 4 Dec 2017 16:51:06 +0000 Subject: perf mmap: Don't discard prev in backward mode 'perf record' can switch its output data file. The new output should only store the data after switching. However, in overwrite backward mode, the new output still can have data from before switching. That also brings extra overhead. At the end of mmap_read(), the position of the processed ring buffer is saved in md->prev. Next mmap_read should be end in md->prev if it is not overwriten. That avoids processing duplicate data. However, md->prev is discarded. So next the mmap_read() has to process whole valid ring buffer, which probably includes old processed data. Avoid calling backward_rb_find_range() when md->prev is still available. Signed-off-by: Wang Nan Tested-by: Kan Liang Acked-by: Namhyung Kim Cc: Jiri Olsa Cc: Mengting Zhang Link: http://lkml.kernel.org/r/20171204165107.95327-3-wangnan0@huawei.com Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/util/mmap.c | 33 +++++++++++++++------------------ 1 file changed, 15 insertions(+), 18 deletions(-) (limited to 'tools/perf/util/mmap.c') diff --git a/tools/perf/util/mmap.c b/tools/perf/util/mmap.c index 3f262e707a41..5f8cb1583e53 100644 --- a/tools/perf/util/mmap.c +++ b/tools/perf/util/mmap.c @@ -267,18 +267,6 @@ static int backward_rb_find_range(void *buf, int mask, u64 head, u64 *start, u64 return -1; } -static int rb_find_range(void *data, int mask, u64 head, u64 old, - u64 *start, u64 *end, bool backward) -{ - if (!backward) { - *start = old; - *end = head; - return 0; - } - - return backward_rb_find_range(data, mask, head, start, end); -} - int perf_mmap__push(struct perf_mmap *md, bool backward, void *to, int push(void *to, void *buf, size_t size)) { @@ -290,19 +278,28 @@ int perf_mmap__push(struct perf_mmap *md, bool backward, void *buf; int rc = 0; - if (rb_find_range(data, md->mask, head, old, &start, &end, backward)) - return -1; + start = backward ? head : old; + end = backward ? old : head; if (start == end) return 0; size = end - start; if (size > (unsigned long)(md->mask) + 1) { - WARN_ONCE(1, "failed to keep up with mmap data. (warn only once)\n"); + if (!backward) { + WARN_ONCE(1, "failed to keep up with mmap data. (warn only once)\n"); - md->prev = head; - perf_mmap__consume(md, backward); - return 0; + md->prev = head; + perf_mmap__consume(md, backward); + return 0; + } + + /* + * Backward ring buffer is full. We still have a chance to read + * most of data from it. + */ + if (backward_rb_find_range(data, md->mask, head, &start, &end)) + return -1; } if ((start & md->mask) + size != (end & md->mask)) { -- cgit v1.2.3 From 0b72d69a542873ee098867deeb37d27ad4629c64 Mon Sep 17 00:00:00 2001 From: Wang Nan Date: Mon, 4 Dec 2017 16:51:07 +0000 Subject: perf tools: Rename 'backward' to 'overwrite' in evlist, mmap and record Remove the backward/forward concept to make it uniform with user interface (the '--overwrite' option). Signed-off-by: Wang Nan Acked-by: Namhyung Kim Cc: Jiri Olsa Cc: Kan Liang Cc: Mengting Zhang Link: http://lkml.kernel.org/r/20171204165107.95327-4-wangnan0@huawei.com Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/util/mmap.c | 22 +++++++++++----------- 1 file changed, 11 insertions(+), 11 deletions(-) (limited to 'tools/perf/util/mmap.c') diff --git a/tools/perf/util/mmap.c b/tools/perf/util/mmap.c index 5f8cb1583e53..05076e683938 100644 --- a/tools/perf/util/mmap.c +++ b/tools/perf/util/mmap.c @@ -234,18 +234,18 @@ int perf_mmap__mmap(struct perf_mmap *map, struct mmap_params *mp, int fd) return 0; } -static int backward_rb_find_range(void *buf, int mask, u64 head, u64 *start, u64 *end) +static int overwrite_rb_find_range(void *buf, int mask, u64 head, u64 *start, u64 *end) { struct perf_event_header *pheader; u64 evt_head = head; int size = mask + 1; - pr_debug2("backward_rb_find_range: buf=%p, head=%"PRIx64"\n", buf, head); + pr_debug2("overwrite_rb_find_range: buf=%p, head=%"PRIx64"\n", buf, head); pheader = (struct perf_event_header *)(buf + (head & mask)); *start = head; while (true) { if (evt_head - head >= (unsigned int)size) { - pr_debug("Finished reading backward ring buffer: rewind\n"); + pr_debug("Finished reading overwrite ring buffer: rewind\n"); if (evt_head - head > (unsigned int)size) evt_head -= pheader->size; *end = evt_head; @@ -255,7 +255,7 @@ static int backward_rb_find_range(void *buf, int mask, u64 head, u64 *start, u64 pheader = (struct perf_event_header *)(buf + (evt_head & mask)); if (pheader->size == 0) { - pr_debug("Finished reading backward ring buffer: get start\n"); + pr_debug("Finished reading overwrite ring buffer: get start\n"); *end = evt_head; return 0; } @@ -267,7 +267,7 @@ static int backward_rb_find_range(void *buf, int mask, u64 head, u64 *start, u64 return -1; } -int perf_mmap__push(struct perf_mmap *md, bool backward, +int perf_mmap__push(struct perf_mmap *md, bool overwrite, void *to, int push(void *to, void *buf, size_t size)) { u64 head = perf_mmap__read_head(md); @@ -278,19 +278,19 @@ int perf_mmap__push(struct perf_mmap *md, bool backward, void *buf; int rc = 0; - start = backward ? head : old; - end = backward ? old : head; + start = overwrite ? head : old; + end = overwrite ? old : head; if (start == end) return 0; size = end - start; if (size > (unsigned long)(md->mask) + 1) { - if (!backward) { + if (!overwrite) { WARN_ONCE(1, "failed to keep up with mmap data. (warn only once)\n"); md->prev = head; - perf_mmap__consume(md, backward); + perf_mmap__consume(md, overwrite); return 0; } @@ -298,7 +298,7 @@ int perf_mmap__push(struct perf_mmap *md, bool backward, * Backward ring buffer is full. We still have a chance to read * most of data from it. */ - if (backward_rb_find_range(data, md->mask, head, &start, &end)) + if (overwrite_rb_find_range(data, md->mask, head, &start, &end)) return -1; } @@ -323,7 +323,7 @@ int perf_mmap__push(struct perf_mmap *md, bool backward, } md->prev = head; - perf_mmap__consume(md, backward); + perf_mmap__consume(md, overwrite); out: return rc; } -- cgit v1.2.3