From: Arnaldo Carvalho de Melo <acme@kernel.org>
To: Jiri Olsa <jolsa@redhat.com>
Cc: lkml <linux-kernel@vger.kernel.org>,
Peter Zijlstra <a.p.zijlstra@chello.nl>,
Ingo Molnar <mingo@kernel.org>,
Mark Rutland <mark.rutland@arm.com>,
Namhyung Kim <namhyung@kernel.org>,
Alexander Shishkin <alexander.shishkin@linux.intel.com>,
Michael Petlan <mpetlan@redhat.com>,
Ian Rogers <irogers@google.com>,
nakamura.shun@fujitsu.com, linux-perf-users@vger.kernel.org
Subject: Re: [PATCH 6/7] libperF: Add group support to perf_evsel__open
Date: Wed, 7 Jul 2021 14:43:07 -0300 [thread overview]
Message-ID: <YOXnq2yTVwklbrpO@kernel.org> (raw)
In-Reply-To: <20210706151704.73662-7-jolsa@kernel.org>
Em Tue, Jul 06, 2021 at 05:17:03PM +0200, Jiri Olsa escreveu:
> Adding support to set group_fd in perf_evsel__open
> call and make it to follow the group setup.
>
> Signed-off-by: Jiri Olsa <jolsa@kernel.org>
> ---
> tools/lib/perf/evsel.c | 26 ++++++++++++++++++++++++--
> 1 file changed, 24 insertions(+), 2 deletions(-)
>
> diff --git a/tools/lib/perf/evsel.c b/tools/lib/perf/evsel.c
> index 3e6638d27c45..9ebf7122d476 100644
> --- a/tools/lib/perf/evsel.c
> +++ b/tools/lib/perf/evsel.c
> @@ -17,6 +17,7 @@
> #include <linux/string.h>
> #include <sys/ioctl.h>
> #include <sys/mman.h>
> +#include <asm/bug.h>
>
> void perf_evsel__init(struct perf_evsel *evsel, struct perf_event_attr *attr,
> int idx)
> @@ -76,6 +77,25 @@ sys_perf_event_open(struct perf_event_attr *attr,
> return syscall(__NR_perf_event_open, attr, pid, cpu, group_fd, flags);
> }
>
> +static int get_group_fd(struct perf_evsel *evsel, int cpu, int thread)
> +{
> + struct perf_evsel *leader = evsel->leader;
> + int fd;
> +
> + if (evsel == leader)
> + return -1;
> +
> + /*
> + * Leader must be already processed/open,
> + * if not it's a bug.
> + */
> + BUG_ON(!leader->fd);
Humm, having panics in library code looks ugly, why can't we just return
some errno and let the whatever is using the library to fail gracefully?
I applied the patches so far, will make them available at tmp.perf/core
now.
- Arnaldo
> + fd = FD(leader, cpu, thread);
> + BUG_ON(fd == -1);
> + return fd;
> +}
> +
> int perf_evsel__open(struct perf_evsel *evsel, struct perf_cpu_map *cpus,
> struct perf_thread_map *threads)
> {
> @@ -111,11 +131,13 @@ int perf_evsel__open(struct perf_evsel *evsel, struct perf_cpu_map *cpus,
>
> for (cpu = 0; cpu < cpus->nr; cpu++) {
> for (thread = 0; thread < threads->nr; thread++) {
> - int fd;
> + int fd, group_fd;
> +
> + group_fd = get_group_fd(evsel, cpu, thread);
>
> fd = sys_perf_event_open(&evsel->attr,
> threads->map[thread].pid,
> - cpus->map[cpu], -1, 0);
> + cpus->map[cpu], group_fd, 0);
>
> if (fd < 0)
> return -errno;
> --
> 2.31.1
>
--
- Arnaldo
next prev parent reply other threads:[~2021-07-07 17:43 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-07-06 15:16 [RFCv2 0/7] libperf: Add leader/group info to perf_evsel Jiri Olsa
2021-07-06 15:16 ` [PATCH 1/7] libperf: Change tests to single static and shared binaries Jiri Olsa
2021-07-06 15:16 ` [PATCH 2/7] libperf: Move idx to perf_evsel::idx Jiri Olsa
2021-07-07 14:45 ` Arnaldo Carvalho de Melo
2021-07-07 18:17 ` Jiri Olsa
2021-07-07 18:36 ` Arnaldo Carvalho de Melo
2021-07-07 14:49 ` Arnaldo Carvalho de Melo
2021-07-07 17:48 ` Arnaldo Carvalho de Melo
2021-07-07 18:18 ` Jiri Olsa
2021-07-07 18:17 ` Jiri Olsa
2021-07-06 15:17 ` [PATCH 3/7] libperf: Move leader to perf_evsel::leader Jiri Olsa
2021-07-07 14:53 ` Arnaldo Carvalho de Melo
2021-07-07 18:14 ` Jiri Olsa
2021-07-07 18:34 ` Arnaldo Carvalho de Melo
2021-07-06 15:17 ` [PATCH 4/7] libperf: Move nr_groups to evlist::nr_groups Jiri Olsa
2021-07-06 15:17 ` [PATCH 5/7] libperf: Add perf_evlist__set_leader function Jiri Olsa
2021-07-06 15:17 ` [PATCH 6/7] libperF: Add group support to perf_evsel__open Jiri Olsa
2021-07-07 17:43 ` Arnaldo Carvalho de Melo [this message]
2021-07-07 18:15 ` Jiri Olsa
2021-07-09 17:57 ` [PATCH] libperf: Remove BUG_ON() from library code in get_group_fd(). was " Arnaldo Carvalho de Melo
2021-07-06 15:17 ` [PATCH 7/7] libperf: Add tests for perf_evlist__set_leader function Jiri Olsa
2021-07-09 17:59 ` Arnaldo Carvalho de Melo
2021-07-07 14:47 ` [RFCv2 0/7] libperf: Add leader/group info to perf_evsel Arnaldo Carvalho de Melo
2021-07-07 18:20 ` Jiri Olsa
2021-07-07 18:37 ` Arnaldo Carvalho de Melo
2021-07-09 8:32 ` nakamura.shun
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