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perf evsel: Move ignore_missing_thread() to fallback code

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This patch moves ignore_missing_thread outside the perf_event_open loop.

Doing so, we need to move the retry_open flag a few places higher, with
minimal impact. Furthermore, thread need not be decreased since it won't
get increased by the for loop (since we're jumping back inside), but we
need to check that the nthreads decrease didn't put thread out of range.

The goal is to have fallbacks handled in one place only, since in the
future parallel code, these would be handled separately.

Signed-off-by: Riccardo Mancini <rickyman7@gmail.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lore.kernel.org/lkml/4eca51443c786baaf6811b7cd8e73aafd97f7606.1629490974.git.rickyman7@gmail.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
This commit is contained in:
Riccardo Mancini 2021-08-21 11:19:27 +02:00 committed by Arnaldo Carvalho de Melo
parent 71efc48a4c
commit da7c3b4622
2 changed files with 18 additions and 16 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

29
tools/perf/util/evsel.c
View File

@ -1656,7 +1656,7 @@ static int update_fds(struct evsel *evsel,
return 0;
}
static bool ignore_missing_thread(struct evsel *evsel,
bool evsel__ignore_missing_thread(struct evsel *evsel,
int nr_cpus, int cpu,
struct perf_thread_map *threads,
int thread, int err)
@ -1993,12 +1993,15 @@ fallback_missing_features:
for (thread = 0; thread < nthreads; thread++) {
int fd, group_fd;
retry_open:
if (thread >= nthreads)
break;
if (!evsel->cgrp && !evsel->core.system_wide)
pid = perf_thread_map__pid(threads, thread);
group_fd = get_group_fd(evsel, cpu, thread);
retry_open:
test_attr__ready();
fd = perf_event_open(evsel, pid, cpus->map[cpu],
@ -2016,20 +2019,6 @@ retry_open:
if (fd < 0) {
err = -errno;
if (ignore_missing_thread(evsel, cpus->nr, cpu, threads, thread, err)) {
/*
* We just removed 1 thread, so take a step
* back on thread index and lower the upper
* nthreads limit.
*/
nthreads--;
thread--;
/* ... and pretend like nothing have happened. */
err = 0;
continue;
}
pr_debug2_peo("\nsys_perf_event_open failed, error %d\n",
err);
goto try_fallback;
@ -2069,6 +2058,14 @@ retry_open:
return 0;
try_fallback:
if (evsel__ignore_missing_thread(evsel, cpus->nr, cpu, threads, thread, err)) {
/* We just removed 1 thread, so lower the upper nthreads limit. */
nthreads--;
/* ... and pretend like nothing have happened. */
err = 0;
goto retry_open;
}
/*
* perf stat needs between 5 and 22 fds per CPU. When we run out
* of them try to increase the limits.

5
tools/perf/util/evsel.h
View File

@ -294,6 +294,11 @@ bool evsel__detect_missing_features(struct evsel *evsel);
enum rlimit_action { NO_CHANGE, SET_TO_MAX, INCREASED_MAX };
bool evsel__increase_rlimit(enum rlimit_action *set_rlimit);
bool evsel__ignore_missing_thread(struct evsel *evsel,
int nr_cpus, int cpu,
struct perf_thread_map *threads,
int thread, int err);
struct perf_sample;
void *evsel__rawptr(struct evsel *evsel, struct perf_sample *sample, const char *name);