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Message-ID: <a86103e9-fe26-70ec-7cbd-4a67c68f165d@arm.com>
Date: Thu, 1 Feb 2024 13:59:46 +0000
From: James Clark <james.clark@....com>
To: Ian Rogers <irogers@...gle.com>
Cc: Peter Zijlstra <peterz@...radead.org>, Ingo Molnar <mingo@...hat.com>,
Arnaldo Carvalho de Melo <acme@...nel.org>,
Namhyung Kim <namhyung@...nel.org>, Mark Rutland <mark.rutland@....com>,
Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
Jiri Olsa <jolsa@...nel.org>, Adrian Hunter <adrian.hunter@...el.com>,
Kan Liang <kan.liang@...ux.intel.com>, linux-perf-users@...r.kernel.org,
linux-kernel@...r.kernel.org, tchen168@....edu,
Michael Petlan <mpetlan@...hat.com>
Subject: Re: [PATCH v2 3/3] perf parse-events: Print all errors
On 31/01/2024 13:49, Ian Rogers wrote:
> Prior to this patch the first and the last error encountered during
> parsing are printed. To see other errors verbose needs
> enabling. Unfortunately this can drop useful errors, in particular on
> terms. This patch changes the errors so that instead of the first and
> last all errors are recorded and printed, the underlying data
> structure is changed to a list.
>
> Before:
> ```
> $ perf stat -e 'slots/edge=2/' true
> event syntax error: 'slots/edge=2/'
> \___ Bad event or PMU
>
> Unable to find PMU or event on a PMU of 'slots'
>
> Initial error:
> event syntax error: 'slots/edge=2/'
> \___ Cannot find PMU `slots'. Missing kernel support?
> Run 'perf list' for a list of valid events
>
> Usage: perf stat [<options>] [<command>]
>
> -e, --event <event> event selector. use 'perf list' to list available events
> ```
>
> After:
> ```
> $ perf stat -e 'slots/edge=2/' true
> event syntax error: 'slots/edge=2/'
> \___ Bad event or PMU
>
> Unable to find PMU or event on a PMU of 'slots'
>
> event syntax error: 'slots/edge=2/'
> \___ value too big for format (edge), maximum is 1
>
> event syntax error: 'slots/edge=2/'
> \___ Cannot find PMU `slots'. Missing kernel support?
> Run 'perf list' for a list of valid events
>
> Usage: perf stat [<options>] [<command>]
>
> -e, --event <event> event selector. use 'perf list' to list available events
> ```
>
> Signed-off-by: Ian Rogers <irogers@...gle.com>
Reviewed-by: James Clark <james.clark@....com>
> ---
> Prompted by discussion:
> https://lore.kernel.org/linux-perf-users/9dd303cb-0455-d8ac-ce0c-f4a8320b787b@arm.com/
> ---
> tools/perf/arch/x86/tests/hybrid.c | 5 +-
> tools/perf/tests/expand-cgroup.c | 3 +-
> tools/perf/tests/parse-events.c | 9 ++-
> tools/perf/util/parse-events.c | 92 ++++++++++++++++++------------
> tools/perf/util/parse-events.h | 14 ++---
> tools/perf/util/parse-events.y | 2 -
> 6 files changed, 67 insertions(+), 58 deletions(-)
>
> diff --git a/tools/perf/arch/x86/tests/hybrid.c b/tools/perf/arch/x86/tests/hybrid.c
> index 40f5d17fedab..e221ea104174 100644
> --- a/tools/perf/arch/x86/tests/hybrid.c
> +++ b/tools/perf/arch/x86/tests/hybrid.c
> @@ -259,11 +259,10 @@ static int test_event(const struct evlist_test *e)
> parse_events_error__init(&err);
> ret = parse_events(evlist, e->name, &err);
> if (ret) {
> - pr_debug("failed to parse event '%s', err %d, str '%s'\n",
> - e->name, ret, err.str);
> + pr_debug("failed to parse event '%s', err %d\n", e->name, ret);
> parse_events_error__print(&err, e->name);
> ret = TEST_FAIL;
> - if (strstr(err.str, "can't access trace events"))
> + if (parse_events_error__contains(&err, "can't access trace events"))
> ret = TEST_SKIP;
> } else {
> ret = e->check(evlist);
> diff --git a/tools/perf/tests/expand-cgroup.c b/tools/perf/tests/expand-cgroup.c
> index 9c1a1f18db75..31966ff856f8 100644
> --- a/tools/perf/tests/expand-cgroup.c
> +++ b/tools/perf/tests/expand-cgroup.c
> @@ -127,8 +127,7 @@ static int expand_group_events(void)
> parse_events_error__init(&err);
> ret = parse_events(evlist, event_str, &err);
> if (ret < 0) {
> - pr_debug("failed to parse event '%s', err %d, str '%s'\n",
> - event_str, ret, err.str);
> + pr_debug("failed to parse event '%s', err %d\n", event_str, ret);
> parse_events_error__print(&err, event_str);
> goto out;
> }
> diff --git a/tools/perf/tests/parse-events.c b/tools/perf/tests/parse-events.c
> index fbdf710d5eea..feb5727584d1 100644
> --- a/tools/perf/tests/parse-events.c
> +++ b/tools/perf/tests/parse-events.c
> @@ -2506,11 +2506,10 @@ static int test_event(const struct evlist_test *e)
> parse_events_error__init(&err);
> ret = parse_events(evlist, e->name, &err);
> if (ret) {
> - pr_debug("failed to parse event '%s', err %d, str '%s'\n",
> - e->name, ret, err.str);
> + pr_debug("failed to parse event '%s', err %d\n", e->name, ret);
> parse_events_error__print(&err, e->name);
> ret = TEST_FAIL;
> - if (err.str && strstr(err.str, "can't access trace events"))
> + if (parse_events_error__contains(&err, "can't access trace events"))
> ret = TEST_SKIP;
> } else {
> ret = e->check(evlist);
> @@ -2535,8 +2534,8 @@ static int test_event_fake_pmu(const char *str)
> ret = __parse_events(evlist, str, /*pmu_filter=*/NULL, &err,
> &perf_pmu__fake, /*warn_if_reordered=*/true);
> if (ret) {
> - pr_debug("failed to parse event '%s', err %d, str '%s'\n",
> - str, ret, err.str);
> + pr_debug("failed to parse event '%s', err %d\n",
> + str, ret);
> parse_events_error__print(&err, str);
> }
>
> diff --git a/tools/perf/util/parse-events.c b/tools/perf/util/parse-events.c
> index 66eabcea4242..6f8b0fa17689 100644
> --- a/tools/perf/util/parse-events.c
> +++ b/tools/perf/util/parse-events.c
> @@ -2181,50 +2181,53 @@ int parse_event(struct evlist *evlist, const char *str)
> return ret;
> }
>
> +struct parse_events_error_entry {
> + /** @list: The list the error is part of. */
> + struct list_head list;
> + /** @idx: index in the parsed string */
> + int idx;
> + /** @str: string to display at the index */
> + char *str;
> + /** @help: optional help string */
> + char *help;
> +};
> +
> void parse_events_error__init(struct parse_events_error *err)
> {
> - bzero(err, sizeof(*err));
> + INIT_LIST_HEAD(&err->list);
> }
>
> void parse_events_error__exit(struct parse_events_error *err)
> {
> - zfree(&err->str);
> - zfree(&err->help);
> - zfree(&err->first_str);
> - zfree(&err->first_help);
> + struct parse_events_error_entry *pos, *tmp;
> +
> + list_for_each_entry_safe(pos, tmp, &err->list, list) {
> + zfree(&pos->str);
> + zfree(&pos->help);
> + list_del_init(&pos->list);
> + free(pos);
> + }
> }
>
> void parse_events_error__handle(struct parse_events_error *err, int idx,
> char *str, char *help)
> {
> + struct parse_events_error_entry *entry;
> +
> if (WARN(!str || !err, "WARNING: failed to provide error string or struct\n"))
> goto out_free;
> - switch (err->num_errors) {
> - case 0:
> - err->idx = idx;
> - err->str = str;
> - err->help = help;
> - break;
> - case 1:
> - err->first_idx = err->idx;
> - err->idx = idx;
> - err->first_str = err->str;
> - err->str = str;
> - err->first_help = err->help;
> - err->help = help;
> - break;
> - default:
> - pr_debug("Multiple errors dropping message: %s (%s)\n",
> - err->str, err->help ?: "<no help>");
> - free(err->str);
> - err->str = str;
> - free(err->help);
> - err->help = help;
> - break;
> +
> + entry = zalloc(sizeof(*entry));
> + if (!entry) {
> + pr_err("Failed to allocate memory for event parsing error: %s (%s)\n",
> + str, help ?: "<no help>");
> + goto out_free;
> }
> - err->num_errors++;
> + entry->idx = idx;
> + entry->str = str;
> + entry->help = help;
> + list_add(&entry->list, &err->list);
> return;
> -
> out_free:
> free(str);
> free(help);
> @@ -2294,19 +2297,34 @@ static void __parse_events_error__print(int err_idx, const char *err_str,
> }
> }
>
> -void parse_events_error__print(struct parse_events_error *err,
> +void parse_events_error__print(const struct parse_events_error *err,
> const char *event)
> {
> - if (!err->num_errors)
> - return;
> + struct parse_events_error_entry *pos;
> + bool first = true;
> +
> + list_for_each_entry(pos, &err->list, list) {
> + if (!first)
> + fputs("\n", stderr);
> + __parse_events_error__print(pos->idx, pos->str, pos->help, event);
> + first = false;
> + }
> +}
>
> - __parse_events_error__print(err->idx, err->str, err->help, event);
> +/*
> + * In the list of errors err, do any of the error strings (str) contain the
> + * given needle string?
> + */
> +bool parse_events_error__contains(const struct parse_events_error *err,
> + const char *needle)
> +{
> + struct parse_events_error_entry *pos;
>
> - if (err->num_errors > 1) {
> - fputs("\nInitial error:\n", stderr);
> - __parse_events_error__print(err->first_idx, err->first_str,
> - err->first_help, event);
> + list_for_each_entry(pos, &err->list, list) {
> + if (strstr(pos->str, needle) != NULL)
> + return true;
> }
> + return false;
> }
>
> #undef MAX_WIDTH
> diff --git a/tools/perf/util/parse-events.h b/tools/perf/util/parse-events.h
> index 63c0a36a4bf1..809359e8544e 100644
> --- a/tools/perf/util/parse-events.h
> +++ b/tools/perf/util/parse-events.h
> @@ -130,13 +130,8 @@ struct parse_events_term {
> };
>
> struct parse_events_error {
> - int num_errors; /* number of errors encountered */
> - int idx; /* index in the parsed string */
> - char *str; /* string to display at the index */
> - char *help; /* optional help string */
> - int first_idx;/* as above, but for the first encountered error */
> - char *first_str;
> - char *first_help;
> + /** @list: The head of a list of errors. */
> + struct list_head list;
> };
>
> /* A wrapper around a list of terms for the sake of better type safety. */
> @@ -247,9 +242,10 @@ void parse_events_error__init(struct parse_events_error *err);
> void parse_events_error__exit(struct parse_events_error *err);
> void parse_events_error__handle(struct parse_events_error *err, int idx,
> char *str, char *help);
> -void parse_events_error__print(struct parse_events_error *err,
> +void parse_events_error__print(const struct parse_events_error *err,
> const char *event);
> -
> +bool parse_events_error__contains(const struct parse_events_error *err,
> + const char *needle);
> #ifdef HAVE_LIBELF_SUPPORT
> /*
> * If the probe point starts with '%',
> diff --git a/tools/perf/util/parse-events.y b/tools/perf/util/parse-events.y
> index de098caf0c1c..d70f5d84af92 100644
> --- a/tools/perf/util/parse-events.y
> +++ b/tools/perf/util/parse-events.y
> @@ -536,8 +536,6 @@ tracepoint_name opt_event_config
> list = alloc_list();
> if (!list)
> YYNOMEM;
> - if (error)
> - error->idx = @1.first_column;
>
> err = parse_events_add_tracepoint(list, &parse_state->idx, $1.sys, $1.event,
> error, $2, &@1);
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