From 0479b8b9cf4377df5d2c81506ce93326c31eff40 Mon Sep 17 00:00:00 2001 From: David Ahern Date: Tue, 5 Feb 2013 14:12:42 -0700 Subject: 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 Cc: Frederic Weisbecker Cc: Ingo Molnar Cc: Jiri Olsa Cc: Namhyung Kim Cc: Peter Zijlstra Link: http://lkml.kernel.org/r/1360098762-61827-1-git-send-email-dsahern@gmail.com Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/perf.h | 26 -------------------------- 1 file changed, 26 deletions(-) (limited to 'tools/perf/perf.h') diff --git a/tools/perf/perf.h b/tools/perf/perf.h index 8f3bf38..c2206c8 100644 --- a/tools/perf/perf.h +++ b/tools/perf/perf.h @@ -103,32 +103,6 @@ #include "util/types.h" #include -struct perf_mmap { - void *base; - int mask; - unsigned int prev; -}; - -static inline unsigned int perf_mmap__read_head(struct perf_mmap *mm) -{ - struct perf_event_mmap_page *pc = mm->base; - int head = pc->data_head; - rmb(); - return head; -} - -static inline void perf_mmap__write_tail(struct perf_mmap *md, - unsigned long tail) -{ - struct perf_event_mmap_page *pc = md->base; - - /* - * ensure all reads are done before we write the tail out. - */ - /* mb(); */ - pc->data_tail = tail; -} - /* * prctl(PR_TASK_PERF_EVENTS_DISABLE) will (cheaply) disable all * counters in the current task. -- cgit v1.1