Messages in this thread | | | From | Arnaldo Carvalho de Melo <> | Date | Fri, 11 Oct 2019 11:38:03 -0300 | Subject | Re: [PATCH v1 2/2] perf test: Avoid infinite loop for task exit case |
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Em Fri, Oct 11, 2019 at 05:19:42PM +0800, Leo Yan escreveu: > When execute task exit testing case, Perf tool stucks in this case and > doesn't return back on Arm64 Juno board. > > After dig into this issue, since Juno board has Arm's big.LITTLE CPUs, > thus the PMUs are not compatible between the big CPUs and little CPUs. > This leads to PMU event cannot be enabled properly when the traced task > is migrated from one variant's CPU to another variant. Finally, the > test case runs into infinite loop for cannot read out any event data > after return from polling.
Thanks, I'll go over this after I finish the current pull request,
- Arnaldo
> Eventually, we need to work out formal solution to allow PMU events can > be freely migrated from one CPU variant to another, but this is a > difficult task and a different topic. This patch tries to fix the Perf > test case to avoid infinite loop, when the testing detects 1000 times > retrying for reading empty events, it will directly bail out and return > failure. This allows the Perf tool can continue its other test cases. > > Signed-off-by: Leo Yan <leo.yan@linaro.org> > --- > tools/perf/tests/task-exit.c | 8 ++++++++ > 1 file changed, 8 insertions(+) > > diff --git a/tools/perf/tests/task-exit.c b/tools/perf/tests/task-exit.c > index ca0a6ca43b13..d85c9f608564 100644 > --- a/tools/perf/tests/task-exit.c > +++ b/tools/perf/tests/task-exit.c > @@ -53,6 +53,7 @@ int test__task_exit(struct test *test __maybe_unused, int subtest __maybe_unused > struct perf_cpu_map *cpus; > struct perf_thread_map *threads; > struct mmap *md; > + int retry_count = 0; > > signal(SIGCHLD, sig_handler); > > @@ -132,6 +133,13 @@ int test__task_exit(struct test *test __maybe_unused, int subtest __maybe_unused > out_init: > if (!exited || !nr_exit) { > evlist__poll(evlist, -1); > + > + if (retry_count++ > 1000) { > + pr_debug("Failed after retrying 1000 times\n"); > + err = -1; > + goto out_free_maps; > + } > + > goto retry; > } > > -- > 2.17.1
--
- Arnaldo
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