Merge branch 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull perf updates from Ingo Molnar:
 "Kernel side changes:

   - Clean up the x86 instruction decoder (Masami Hiramatsu)

   - Add new uprobes optimization for PUSH instructions on x86 (Yonghong
     Song)

   - Add MSR_IA32_THERM_STATUS to the MSR events (Stephane Eranian)

   - Fix misc bugs, update documentation, plus various cleanups (Jiri
     Olsa)

  There's a large number of tooling side improvements:

   - Intel-PT/BTS improvements (Adrian Hunter)

   - Numerous 'perf trace' improvements (Arnaldo Carvalho de Melo)

   - Introduce an errno code to string facility (Hendrik Brueckner)

   - Various build system improvements (Jiri Olsa)

   - Add support for CoreSight trace decoding by making the perf tools
     use the external openCSD (Mathieu Poirier, Tor Jeremiassen)

   - Add ARM Statistical Profiling Extensions (SPE) support (Kim
     Phillips)

   - libtraceevent updates (Steven Rostedt)

   - Intel vendor event JSON updates (Andi Kleen)

   - Introduce 'perf report --mmaps' and 'perf report --tasks' to show
     info present in 'perf.data' (Jiri Olsa, Arnaldo Carvalho de Melo)

   - Add infrastructure to record first and last sample time to the
     perf.data file header, so that when processing all samples in a
     'perf record' session, such as when doing build-id processing, or
     when specifically requesting that that info be recorded, use that
     in 'perf report --time', that also got support for percent slices
     in addition to absolute ones.

     I.e. now it is possible to ask for the samples in the 10%-20% time
     slice of a perf.data file (Jin Yao)

   - Allow system wide 'perf stat --per-thread', sorting the result (Jin
     Yao)

     E.g.:

      [root@jouet ~]# perf stat --per-thread --metrics IPC
      ^C
       Performance counter stats for 'system wide':

                  make-22229  23,012,094,032  inst_retired.any   #  0.8 IPC
                   cc1-22419     692,027,497  inst_retired.any   #  0.8 IPC
                   gcc-22418     328,231,855  inst_retired.any   #  0.9 IPC
                   cc1-22509     220,853,647  inst_retired.any   #  0.8 IPC
                   gcc-22486     199,874,810  inst_retired.any   #  1.0 IPC
                    as-22466     177,896,365  inst_retired.any   #  0.9 IPC
                   cc1-22465     150,732,374  inst_retired.any   #  0.8 IPC
                   gcc-22508     112,555,593  inst_retired.any   #  0.9 IPC
                   cc1-22487     108,964,079  inst_retired.any   #  0.7 IPC
       qemu-system-x86-2697       21,330,550  inst_retired.any   #  0.3 IPC
       systemd-journal-551        20,642,951  inst_retired.any   #  0.4 IPC
       docker-containe-17651       9,552,892  inst_retired.any   #  0.5 IPC
       dockerd-current-9809        7,528,586  inst_retired.any   #  0.5 IPC
                  make-22153  12,504,194,380  inst_retired.any   #  0.8 IPC
               python2-22429  12,081,290,954  inst_retired.any   #  0.8 IPC
      <SNIP>
               python2-22429  15,026,328,103  cpu_clk_unhalted.thread
                   cc1-22419     826,660,193  cpu_clk_unhalted.thread
                   gcc-22418     365,321,295  cpu_clk_unhalted.thread
                   cc1-22509     279,169,362  cpu_clk_unhalted.thread
                   gcc-22486     210,156,950  cpu_clk_unhalted.thread
      <SNIP>

           5.638075538 seconds time elapsed

     [root@jouet ~]#

   - Improve shell auto-completion of perf events (Jin Yao)

   - 'perf probe' improvements (Masami Hiramatsu)

   - Improve PMU infrastructure to support amp64's ThunderX2
     implementation defined core events (Ganapatrao Kulkarni)

   - Various annotation related improvements and fixes (Thomas Richter)

   - Clarify usage of 'overwrite' and 'backward' in the evlist/mmap
     code, removing the 'overwrite' parameter from several functions as
     it was always used it as 'false' (Wang Nan)

   - Fix/improve 'perf record' reverse recording support (Wang Nan)

   - Improve command line options documentation (Sihyeon Jang)

   - Optimize sample parsing for ordering events, where we don't need to
     parse all the PERF_SAMPLE_ bits, just the ones leading to the
     timestamp needed to reorder events (Jiri Olsa)

   - Generalize the annotation code to support other source information
     besides objdump/DWARF obtained ones, starting with python scripts,
     that will is slated to be merged soon (Jiri Olsa)

   - ... and a lot more that I failed to list, see the shortlog and
     changelog for details"

* 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (262 commits)
  perf trace beauty flock: Move to separate object file
  perf evlist: Remove fcntl.h from evlist.h
  perf trace beauty futex: Beautify FUTEX_BITSET_MATCH_ANY
  perf trace: Do not print from time delta for interrupted syscall lines
  perf trace: Add --print-sample
  perf bpf: Remove misplaced __maybe_unused attribute
  MAINTAINERS: Adding entry for CoreSight trace decoding
  perf tools: Add mechanic to synthesise CoreSight trace packets
  perf tools: Add full support for CoreSight trace decoding
  pert tools: Add queue management functionality
  perf tools: Add functionality to communicate with the openCSD decoder
  perf tools: Add support for decoding CoreSight trace data
  perf tools: Add decoder mechanic to support dumping trace data
  perf tools: Add processing of coresight metadata
  perf tools: Add initial entry point for decoder CoreSight traces
  perf tools: Integrating the CoreSight decoding library
  perf vendor events intel: Update IvyTown files to V20
  perf vendor events intel: Update IvyBridge files to V20
  perf vendor events intel: Update BroadwellDE events to V7
  perf vendor events intel: Update SkylakeX events to V1.06
  ...

1 files changed, 25 insertions, 48 deletions

diff --git a/tools/perf/util/mmap.c b/tools/perf/util/mmap.c
index 9fe5f9c7d577..05076e683938 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)
@@ -254,18 +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;
@@ -275,7 +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;
 		}
@@ -287,19 +267,7 @@ 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 overwrite, 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);
@@ -310,19 +278,28 @@ int perf_mmap__push(struct perf_mmap *md, bool overwrite, bool backward,
 	void *buf;
 	int rc = 0;
 
-	if (rb_find_range(data, md->mask, head, old, &start, &end, backward))
-		return -1;
+	start = overwrite ? head : old;
+	end = overwrite ? 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 (!overwrite) {
+			WARN_ONCE(1, "failed to keep up with mmap data. (warn only once)\n");
 
-		md->prev = head;
-		perf_mmap__consume(md, overwrite || backward);
-		return 0;
+			md->prev = head;
+			perf_mmap__consume(md, overwrite);
+			return 0;
+		}
+
+		/*
+		 * Backward ring buffer is full. We still have a chance to read
+		 * most of data from it.
+		 */
+		if (overwrite_rb_find_range(data, md->mask, head, &start, &end))
+			return -1;
 	}
 
 	if ((start & md->mask) + size != (end & md->mask)) {
@@ -346,7 +323,7 @@ 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, overwrite);
 out:
 	return rc;
 }