diff options
author | Ian Rogers <irogers@google.com> | 2021-12-23 21:56:22 +0300 |
---|---|---|
committer | Arnaldo Carvalho de Melo <acme@redhat.com> | 2022-02-15 23:15:33 +0300 |
commit | 87a73bdc421ac702c248002a0a2e62f08c6e7682 (patch) | |
tree | 017df856afa33bc346462b180a243c15f0cbf9b6 /tools/perf/tests | |
parent | aca8af3c2e8cb57662e6035c0ccb3c111a11d97a (diff) | |
download | linux-87a73bdc421ac702c248002a0a2e62f08c6e7682.tar.xz |
perf test: Make metric testing more robust
When testing metric expressions we fake counter values from 1 going
upward. For some metrics this can yield negative values that are clipped
to zero, and then cause divide by zero failures.
Such clipping is questionable but may be a result of tools automatically
generating metrics. A workaround for this case is to try a second time
with counter values going in the opposite direction.
This case was seen in a metric like:
event1 / max(event2 - event3, 0)
But it may also happen in more sensible metrics like:
event1 / (event2 + event3 - 1 - event4)
Reviewed-by: John Garry <john.garry@huawei.com>
Signed-off-by: Ian Rogers <irogers@google.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Kajol Jain <kjain@linux.ibm.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: https://lore.kernel.org/r/20211223185622.3435128-1-irogers@google.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Diffstat (limited to 'tools/perf/tests')
-rw-r--r-- | tools/perf/tests/pmu-events.c | 32 |
1 files changed, 26 insertions, 6 deletions
diff --git a/tools/perf/tests/pmu-events.c b/tools/perf/tests/pmu-events.c index 1c695fb5a79c..299a215eb54c 100644 --- a/tools/perf/tests/pmu-events.c +++ b/tools/perf/tests/pmu-events.c @@ -994,8 +994,18 @@ static int test__parsing(struct test_suite *test __maybe_unused, } if (expr__parse(&result, ctx, pe->metric_expr)) { - expr_failure("Parse failed", map, pe); - ret++; + /* + * Parsing failed, make numbers go from large to + * small which can resolve divide by zero + * issues. + */ + k = 1024; + hashmap__for_each_entry(ctx->ids, cur, bkt) + expr__add_id_val(ctx, strdup(cur->key), k--); + if (expr__parse(&result, ctx, pe->metric_expr)) { + expr_failure("Parse failed", map, pe); + ret++; + } } } } @@ -1054,10 +1064,20 @@ static int metric_parse_fake(const char *str) } } - if (expr__parse(&result, ctx, str)) - pr_err("expr__parse failed\n"); - else - ret = 0; + ret = 0; + if (expr__parse(&result, ctx, str)) { + /* + * Parsing failed, make numbers go from large to small which can + * resolve divide by zero issues. + */ + i = 1024; + hashmap__for_each_entry(ctx->ids, cur, bkt) + expr__add_id_val(ctx, strdup(cur->key), i--); + if (expr__parse(&result, ctx, str)) { + pr_err("expr__parse failed\n"); + ret = -1; + } + } out: expr__ctx_free(ctx); |