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authorThomas Richter <tmricht@linux.ibm.com>2019-04-23 12:53:03 +0200
committerArnaldo Carvalho de Melo <acme@redhat.com>2019-05-02 16:00:20 -0400
commit167e418fa0871c083e2c74508d73012abb01e6f7 (patch)
tree126d376a72d1bbe371bcb6a81b7202d76f0ee880
parentbf561d3c13423fc54daa19b5d49dc15fafdb7acc (diff)
perf report: Report OOM in status line in the GTK UI
An -ENOMEM error is not reported in the GTK GUI. Instead this error message pops up on the screen: [root@m35lp76 perf]# ./perf report -i perf.data.error68-1 Processing events... [974K/3M] Error:failed to process sample 0xf4198 [0x8]: failed to process type: 68 However when I use the same perf.data file with --stdio it works: [root@m35lp76 perf]# ./perf report -i perf.data.error68-1 --stdio \ | head -12 # Total Lost Samples: 0 # # Samples: 76K of event 'cycles' # Event count (approx.): 99056160000 # # Overhead Command Shared Object Symbol # ........ ............... ................. ......... # 8.81% find [kernel.kallsyms] [k] ftrace_likely_update 8.74% swapper [kernel.kallsyms] [k] ftrace_likely_update 8.34% sshd [kernel.kallsyms] [k] ftrace_likely_update 2.19% kworker/u512:1- [kernel.kallsyms] [k] ftrace_likely_update The sample precentage is a bit low..... The GUI always fails in the FINISHED_ROUND event (68) and does not indicate the reason why. When happened is the following. Perf report calls a lot of functions and down deep when a FINISHED_ROUND event is processed, these functions are called: perf_session__process_event() + perf_session__process_user_event() + process_finished_round() + ordered_events__flush() + __ordered_events__flush() + do_flush() + ordered_events__deliver_event() + perf_session__deliver_event() + machine__deliver_event() + perf_evlist__deliver_event() + process_sample_event() + hist_entry_iter_add() --> only called in GUI case!!! + hist_iter__report__callback() + symbol__inc_addr_sample() Now this functions runs out of memory and returns -ENOMEM. This is reported all the way up until function perf_session__process_event() returns to its caller, where -ENOMEM is changed to -EINVAL and processing stops: if ((skip = perf_session__process_event(session, event, head)) < 0) { pr_err("%#" PRIx64 " [%#x]: failed to process type: %d\n", head, event->header.size, event->header.type); err = -EINVAL; goto out_err; } This occurred in the FINISHED_ROUND event when it has to process some 10000 entries and ran out of memory. This patch indicates the root cause and displays it in the status line of ther perf report GUI. Output before (on GUI status line): 0xf4198 [0x8]: failed to process type: 68 Output after: 0xf4198 [0x8]: failed to process type: 68 [not enough memory] Committer notes: the 'skip' variable needs to be initialized to -EINVAL, so that when the size is less than sizeof(struct perf_event_attr) we avoid this valid compiler warning: util/session.c: In function ‘perf_session__process_events’: util/session.c:1936:7: error: ‘skip’ may be used uninitialized in this function [-Werror=maybe-uninitialized] err = skip; ~~~~^~~~~~ util/session.c:1874:6: note: ‘skip’ was declared here s64 skip; ^~~~ cc1: all warnings being treated as errors Signed-off-by: Thomas Richter <tmricht@linux.ibm.com> Reviewed-by: Hendrik Brueckner <brueckner@linux.ibm.com> Reviewed-by: Jiri Olsa <jolsa@redhat.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Link: http://lkml.kernel.org/r/20190423105303.61683-1-tmricht@linux.ibm.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
-rw-r--r--tools/perf/util/session.c8
1 files changed, 5 insertions, 3 deletions
diff --git a/tools/perf/util/session.c b/tools/perf/util/session.c
index b17f1c9bc965..bad5f87ae001 100644
--- a/tools/perf/util/session.c
+++ b/tools/perf/util/session.c
@@ -1928,12 +1928,14 @@ more:
size = event->header.size;
+ skip = -EINVAL;
+
if (size < sizeof(struct perf_event_header) ||
(skip = rd->process(session, event, file_pos)) < 0) {
- pr_err("%#" PRIx64 " [%#x]: failed to process type: %d\n",
+ pr_err("%#" PRIx64 " [%#x]: failed to process type: %d [%s]\n",
file_offset + head, event->header.size,
- event->header.type);
- err = -EINVAL;
+ event->header.type, strerror(-skip));
+ err = skip;
goto out;
}