From 5622c07b4741e0afd7607bce6e850b76eeb23210 Mon Sep 17 00:00:00 2001 From: Stephane Eranian Date: Fri, 27 Apr 2012 14:45:38 +0200 Subject: perf stat: Fix case where guest/host monitoring is not supported by kernel By default, perf stat sets exclude_guest = 1. But when you run perf on a kernel which does not support host/guest filtering, then you get an error saying the event in unsupported. This comes from the fact that when the perf_event_attr struct passed by the user is larger than the one known to the kernel there is safety check which ensures that all unknown bits are zero. But here, exclude_guest is 1 (part of the unknown bits) and thus the perf_event_open() syscall return EINVAL. To my surprise, running perf record on the same kernel did not exhibit the problem. The reason is that perf record handles the problem by catching the error and retrying with guest/host excludes set to zero. For some reason, this was not done with perf stat. This patch fixes this problem. Signed-off-by: Stephane Eranian Cc: Gleb Natapov Cc: Ingo Molnar Cc: Joerg Roedel Cc: Peter Zijlstra Cc: Robert Richter Link: http://lkml.kernel.org/r/20120427124538.GA7230@quad Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/builtin-stat.c | 33 +++++++++++++++++++++++++++++---- 1 file changed, 29 insertions(+), 4 deletions(-) (limited to 'tools/perf/builtin-stat.c') diff --git a/tools/perf/builtin-stat.c b/tools/perf/builtin-stat.c index c941bb640f49..4532a789fbe3 100644 --- a/tools/perf/builtin-stat.c +++ b/tools/perf/builtin-stat.c @@ -283,6 +283,8 @@ static int create_perf_stat_counter(struct perf_evsel *evsel, { struct perf_event_attr *attr = &evsel->attr; struct xyarray *group_fd = NULL; + bool exclude_guest_missing = false; + int ret; if (group && evsel != first) group_fd = first->fd; @@ -293,16 +295,39 @@ static int create_perf_stat_counter(struct perf_evsel *evsel, attr->inherit = !no_inherit; - if (system_wide) - return perf_evsel__open_per_cpu(evsel, evsel_list->cpus, +retry: + if (exclude_guest_missing) + evsel->attr.exclude_guest = evsel->attr.exclude_host = 0; + + if (system_wide) { + ret = perf_evsel__open_per_cpu(evsel, evsel_list->cpus, group, group_fd); + if (ret) + goto check_ret; + return 0; + } + if (!target_pid && !target_tid && (!group || evsel == first)) { attr->disabled = 1; attr->enable_on_exec = 1; } - return perf_evsel__open_per_thread(evsel, evsel_list->threads, - group, group_fd); + ret = perf_evsel__open_per_thread(evsel, evsel_list->threads, + group, group_fd); + if (!ret) + return 0; + /* fall through */ +check_ret: + if (ret && errno == EINVAL) { + if (!exclude_guest_missing && + (evsel->attr.exclude_guest || evsel->attr.exclude_host)) { + pr_debug("Old kernel, cannot exclude " + "guest or host samples.\n"); + exclude_guest_missing = true; + goto retry; + } + } + return ret; } /* -- cgit v1.2.3 From 20d23aaa31da295378abff4272716e3dfc72baf0 Mon Sep 17 00:00:00 2001 From: David Ahern Date: Tue, 8 May 2012 09:29:16 -0600 Subject: perf stat: handle ENXIO error for perf_event_open perf stat on PPC currently fails to run: $ perf stat -- sleep 1 Error: open_counter returned with 6 (No such device or address). /bin/dmesg may provide additional information. Fatal: Not all events could be opened. The problem is that until 2.6.37 (behavior changed with commit b0a873e) perf on PPC returns ENXIO when hw_perf_event_init() fails. With this patch we get the expected behavior: $ perf stat -v -- sleep 1 cycles event is not supported by the kernel. stalled-cycles-frontend event is not supported by the kernel. stalled-cycles-backend event is not supported by the kernel. instructions event is not supported by the kernel. branches event is not supported by the kernel. branch-misses event is not supported by the kernel. ... Signed-off-by: David Ahern Cc: Peter Zijlstra Link: http://lkml.kernel.org/r/1336490956-57145-1-git-send-email-dsahern@gmail.com Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/builtin-stat.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) (limited to 'tools/perf/builtin-stat.c') diff --git a/tools/perf/builtin-stat.c b/tools/perf/builtin-stat.c index 4532a789fbe3..1e5e9b270f5e 100644 --- a/tools/perf/builtin-stat.c +++ b/tools/perf/builtin-stat.c @@ -488,8 +488,13 @@ static int run_perf_stat(int argc __used, const char **argv) list_for_each_entry(counter, &evsel_list->entries, node) { if (create_perf_stat_counter(counter, first) < 0) { + /* + * PPC returns ENXIO for HW counters until 2.6.37 + * (behavior changed with commit b0a873e). + */ if (errno == EINVAL || errno == ENOSYS || - errno == ENOENT || errno == EOPNOTSUPP) { + errno == ENOENT || errno == EOPNOTSUPP || + errno == ENXIO) { if (verbose) ui__warning("%s event is not supported by the kernel.\n", event_name(counter)); -- cgit v1.2.3