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Message-ID: <CAP-5=fUb9muc-5ncaOvWjciXydOhiS7S+5y_L8QR=A-PDU2jCw@mail.gmail.com>
Date: Fri, 23 Sep 2022 19:49:14 -0700
From: Ian Rogers <irogers@...gle.com>
To: Namhyung Kim <namhyung@...nel.org>
Cc: Arnaldo Carvalho de Melo <acme@...nel.org>,
Jiri Olsa <jolsa@...nel.org>, Ingo Molnar <mingo@...nel.org>,
Peter Zijlstra <peterz@...radead.org>,
LKML <linux-kernel@...r.kernel.org>,
Adrian Hunter <adrian.hunter@...el.com>,
linux-perf-users@...r.kernel.org
Subject: Re: [PATCH 1/3] perf lock: Add -E/--entries option
On Fri, Sep 23, 2022 at 5:42 PM Namhyung Kim <namhyung@...nel.org> wrote:
>
> Like perf top, the -E option can limit number of entries to print.
> It can be useful when users want to see top N contended locks only.
>
> Signed-off-by: Namhyung Kim <namhyung@...nel.org>
Acked-by: Ian Rogers <irogers@...gle.com>
Thanks,
Ian
> ---
> tools/perf/Documentation/perf-lock.txt | 10 ++++++++++
> tools/perf/builtin-lock.c | 20 +++++++++++++++-----
> 2 files changed, 25 insertions(+), 5 deletions(-)
>
> diff --git a/tools/perf/Documentation/perf-lock.txt b/tools/perf/Documentation/perf-lock.txt
> index 5f2dc634258e..b23e76200ac2 100644
> --- a/tools/perf/Documentation/perf-lock.txt
> +++ b/tools/perf/Documentation/perf-lock.txt
> @@ -94,6 +94,11 @@ REPORT OPTIONS
> EventManager_De 1845 1 636
> futex-default-S 1609 0 0
>
> +-E::
> +--entries=<value>::
> + Display this many entries.
> +
> +
> INFO OPTIONS
> ------------
>
> @@ -105,6 +110,7 @@ INFO OPTIONS
> --map::
> dump map of lock instances (address:name table)
>
> +
> CONTENTION OPTIONS
> --------------
>
> @@ -154,6 +160,10 @@ CONTENTION OPTIONS
> --stack-skip
> Number of stack depth to skip when finding a lock caller (default: 3).
>
> +-E::
> +--entries=<value>::
> + Display this many entries.
> +
>
> SEE ALSO
> --------
> diff --git a/tools/perf/builtin-lock.c b/tools/perf/builtin-lock.c
> index 25d75fa09b90..1c0d52384d9e 100644
> --- a/tools/perf/builtin-lock.c
> +++ b/tools/perf/builtin-lock.c
> @@ -58,6 +58,7 @@ static bool use_bpf;
> static unsigned long bpf_map_entries = 10240;
> static int max_stack_depth = CONTENTION_STACK_DEPTH;
> static int stack_skip = CONTENTION_STACK_SKIP;
> +static int print_nr_entries = INT_MAX / 2;
>
> static enum {
> LOCK_AGGR_ADDR,
> @@ -1266,14 +1267,14 @@ static void print_result(void)
> struct lock_stat *st;
> struct lock_key *key;
> char cut_name[20];
> - int bad, total;
> + int bad, total, printed;
>
> pr_info("%20s ", "Name");
> list_for_each_entry(key, &lock_keys, list)
> pr_info("%*s ", key->len, key->header);
> pr_info("\n\n");
>
> - bad = total = 0;
> + bad = total = printed = 0;
> while ((st = pop_from_result())) {
> total++;
> if (st->broken)
> @@ -1311,6 +1312,9 @@ static void print_result(void)
> pr_info(" ");
> }
> pr_info("\n");
> +
> + if (++printed >= print_nr_entries)
> + break;
> }
>
> print_bad_events(bad, total);
> @@ -1476,7 +1480,7 @@ static void print_contention_result(struct lock_contention *con)
> {
> struct lock_stat *st;
> struct lock_key *key;
> - int bad, total;
> + int bad, total, printed;
>
> list_for_each_entry(key, &lock_keys, list)
> pr_info("%*s ", key->len, key->header);
> @@ -1486,7 +1490,7 @@ static void print_contention_result(struct lock_contention *con)
> else
> pr_info(" %10s %s\n\n", "type", "caller");
>
> - bad = total = 0;
> + bad = total = printed = 0;
> if (use_bpf)
> bad = bad_hist[BROKEN_CONTENDED];
>
> @@ -1507,7 +1511,7 @@ static void print_contention_result(struct lock_contention *con)
> /* st->addr contains tid of thread */
> t = perf_session__findnew(session, pid);
> pr_info(" %10d %s\n", pid, thread__comm_str(t));
> - continue;
> + goto next;
> }
>
> pr_info(" %10s %s\n", get_type_str(st), st->name);
> @@ -1527,6 +1531,10 @@ static void print_contention_result(struct lock_contention *con)
> pr_info("\t\t\t%#lx %s\n", (unsigned long)ip, buf);
> }
> }
> +
> +next:
> + if (++printed >= print_nr_entries)
> + break;
> }
>
> print_bad_events(bad, total);
> @@ -1878,6 +1886,7 @@ int cmd_lock(int argc, const char **argv)
> "combine locks in the same class"),
> OPT_BOOLEAN('t', "threads", &show_thread_stats,
> "show per-thread lock stats"),
> + OPT_INTEGER('E', "entries", &print_nr_entries, "display this many functions"),
> OPT_PARENT(lock_options)
> };
>
> @@ -1905,6 +1914,7 @@ int cmd_lock(int argc, const char **argv)
> OPT_INTEGER(0, "stack-skip", &stack_skip,
> "Set the number of stack depth to skip when finding a lock caller, "
> "Default: " __stringify(CONTENTION_STACK_SKIP)),
> + OPT_INTEGER('E', "entries", &print_nr_entries, "display this many functions"),
> OPT_PARENT(lock_options)
> };
>
> --
> 2.37.3.998.g577e59143f-goog
>
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