aboutsummaryrefslogtreecommitdiffstats
path: root/tools/perf
diff options
context:
space:
mode:
authorDavid Ahern <dsahern@gmail.com>2013-02-05 16:12:42 -0500
committerArnaldo Carvalho de Melo <acme@redhat.com>2013-02-06 16:09:26 -0500
commit0479b8b9cf4377df5d2c81506ce93326c31eff40 (patch)
treedff61dc7107f5b6563915b02347597489687fc1c /tools/perf
parent5936f54d6ca2857d81188dcdff8c61b8fc482f53 (diff)
perf evlist: Make event_copy local to mmaps
I am getting segfaults *after* the time sorting of perf samples where the event type is off the charts: (gdb) bt \#0 0x0807b1b2 in hists__inc_nr_events (hists=0x80a99c4, type=1163281902) at util/hist.c:1225 \#1 0x08070795 in perf_session_deliver_event (session=0x80a9b90, event=0xf7a6aff8, sample=0xffffc318, tool=0xffffc520, file_offset=0) at util/session.c:884 \#2 0x0806f9b9 in flush_sample_queue (s=0x80a9b90, tool=0xffffc520) at util/session.c:555 \#3 0x0806fc53 in process_finished_round (tool=0xffffc520, event=0x0, session=0x80a9b90) at util/session.c:645 This is bizarre because the event has already been processed once -- before it was added to the samples queue -- and the event was found to be sane at that time. There seem to be 2 causes: 1. perf_evlist__mmap_read updates the read location even though there are outstanding references to events sitting in the mmap buffers via the ordered samples queue. 2. There is a single evlist->event_copy for all evlist entries. event_copy is used to handle an event wrapping at the mmap buffer boundary. This patch addresses the second problem - making event_copy local to each perf_mmap. With this change my highly repeatable use case no longer fails. The first problem is much more complicated and will be the subject of a future patch. Signed-off-by: David Ahern <dsahern@gmail.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/1360098762-61827-1-git-send-email-dsahern@gmail.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Diffstat (limited to 'tools/perf')
-rw-r--r--tools/perf/perf.h26
-rw-r--r--tools/perf/util/evlist.c4
-rw-r--r--tools/perf/util/evlist.h29
3 files changed, 30 insertions, 29 deletions
diff --git a/tools/perf/perf.h b/tools/perf/perf.h
index 8f3bf388e414..c2206c87fc9f 100644
--- a/tools/perf/perf.h
+++ b/tools/perf/perf.h
@@ -103,32 +103,6 @@
103#include "util/types.h" 103#include "util/types.h"
104#include <stdbool.h> 104#include <stdbool.h>
105 105
106struct perf_mmap {
107 void *base;
108 int mask;
109 unsigned int prev;
110};
111
112static inline unsigned int perf_mmap__read_head(struct perf_mmap *mm)
113{
114 struct perf_event_mmap_page *pc = mm->base;
115 int head = pc->data_head;
116 rmb();
117 return head;
118}
119
120static inline void perf_mmap__write_tail(struct perf_mmap *md,
121 unsigned long tail)
122{
123 struct perf_event_mmap_page *pc = md->base;
124
125 /*
126 * ensure all reads are done before we write the tail out.
127 */
128 /* mb(); */
129 pc->data_tail = tail;
130}
131
132/* 106/*
133 * prctl(PR_TASK_PERF_EVENTS_DISABLE) will (cheaply) disable all 107 * prctl(PR_TASK_PERF_EVENTS_DISABLE) will (cheaply) disable all
134 * counters in the current task. 108 * counters in the current task.
diff --git a/tools/perf/util/evlist.c b/tools/perf/util/evlist.c
index ecf123e080bb..bc4ad7977438 100644
--- a/tools/perf/util/evlist.c
+++ b/tools/perf/util/evlist.c
@@ -375,7 +375,7 @@ union perf_event *perf_evlist__mmap_read(struct perf_evlist *evlist, int idx)
375 if ((old & md->mask) + size != ((old + size) & md->mask)) { 375 if ((old & md->mask) + size != ((old + size) & md->mask)) {
376 unsigned int offset = old; 376 unsigned int offset = old;
377 unsigned int len = min(sizeof(*event), size), cpy; 377 unsigned int len = min(sizeof(*event), size), cpy;
378 void *dst = &evlist->event_copy; 378 void *dst = &md->event_copy;
379 379
380 do { 380 do {
381 cpy = min(md->mask + 1 - (offset & md->mask), len); 381 cpy = min(md->mask + 1 - (offset & md->mask), len);
@@ -385,7 +385,7 @@ union perf_event *perf_evlist__mmap_read(struct perf_evlist *evlist, int idx)
385 len -= cpy; 385 len -= cpy;
386 } while (len); 386 } while (len);
387 387
388 event = &evlist->event_copy; 388 event = &md->event_copy;
389 } 389 }
390 390
391 old += size; 391 old += size;
diff --git a/tools/perf/util/evlist.h b/tools/perf/util/evlist.h
index 73579a25a93e..2dd07bd60b4f 100644
--- a/tools/perf/util/evlist.h
+++ b/tools/perf/util/evlist.h
@@ -17,6 +17,13 @@ struct perf_record_opts;
17#define PERF_EVLIST__HLIST_BITS 8 17#define PERF_EVLIST__HLIST_BITS 8
18#define PERF_EVLIST__HLIST_SIZE (1 << PERF_EVLIST__HLIST_BITS) 18#define PERF_EVLIST__HLIST_SIZE (1 << PERF_EVLIST__HLIST_BITS)
19 19
20struct perf_mmap {
21 void *base;
22 int mask;
23 unsigned int prev;
24 union perf_event event_copy;
25};
26
20struct perf_evlist { 27struct perf_evlist {
21 struct list_head entries; 28 struct list_head entries;
22 struct hlist_head heads[PERF_EVLIST__HLIST_SIZE]; 29 struct hlist_head heads[PERF_EVLIST__HLIST_SIZE];
@@ -30,7 +37,6 @@ struct perf_evlist {
30 pid_t pid; 37 pid_t pid;
31 } workload; 38 } workload;
32 bool overwrite; 39 bool overwrite;
33 union perf_event event_copy;
34 struct perf_mmap *mmap; 40 struct perf_mmap *mmap;
35 struct pollfd *pollfd; 41 struct pollfd *pollfd;
36 struct thread_map *threads; 42 struct thread_map *threads;
@@ -136,4 +142,25 @@ static inline struct perf_evsel *perf_evlist__last(struct perf_evlist *evlist)
136} 142}
137 143
138size_t perf_evlist__fprintf(struct perf_evlist *evlist, FILE *fp); 144size_t perf_evlist__fprintf(struct perf_evlist *evlist, FILE *fp);
145
146static inline unsigned int perf_mmap__read_head(struct perf_mmap *mm)
147{
148 struct perf_event_mmap_page *pc = mm->base;
149 int head = pc->data_head;
150 rmb();
151 return head;
152}
153
154static inline void perf_mmap__write_tail(struct perf_mmap *md,
155 unsigned long tail)
156{
157 struct perf_event_mmap_page *pc = md->base;
158
159 /*
160 * ensure all reads are done before we write the tail out.
161 */
162 /* mb(); */
163 pc->data_tail = tail;
164}
165
139#endif /* __PERF_EVLIST_H */ 166#endif /* __PERF_EVLIST_H */