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Message-ID: <YS6JBBW3d4pmcy/U@kernel.org>
Date: Tue, 31 Aug 2021 16:54:44 -0300
From: Arnaldo Carvalho de Melo <acme@...nel.org>
To: Riccardo Mancini <rickyman7@...il.com>
Cc: Ian Rogers <irogers@...gle.com>,
Namhyung Kim <namhyung@...nel.org>,
Peter Zijlstra <peterz@...radead.org>,
Ingo Molnar <mingo@...hat.com>,
Mark Rutland <mark.rutland@....com>,
Jiri Olsa <jolsa@...hat.com>, linux-kernel@...r.kernel.org,
linux-perf-users@...r.kernel.org
Subject: Re: [RFC PATCH v1 25/37] perf evsel: move event open in
evsel__open_cpu to separate function
Em Sat, Aug 21, 2021 at 11:19:31AM +0200, Riccardo Mancini escreveu:
> This is the final patch splitting evsel__open_cpu.
> This patch moves the entire loop code to a separate function, to be
> reused for the multithreaded code.
Are you going to use that 'enum perf_event_open_err' somewhere else?
I.e. is there a need to expose it in evsel.h?
I'm stopping at this patch to give the ones I merged so far some
testing, will now push it to tmp.perf/core.
- Arnaldo
> Signed-off-by: Riccardo Mancini <rickyman7@...il.com>
> ---
> tools/perf/util/evsel.c | 142 ++++++++++++++++++++++++----------------
> tools/perf/util/evsel.h | 12 ++++
> 2 files changed, 99 insertions(+), 55 deletions(-)
>
> diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c
> index 2e95416b8320c6b9..e41f55a7a70ea630 100644
> --- a/tools/perf/util/evsel.c
> +++ b/tools/perf/util/evsel.c
> @@ -1945,6 +1945,82 @@ bool evsel__increase_rlimit(enum rlimit_action *set_rlimit)
> return false;
> }
>
> +static struct perf_event_open_result perf_event_open(struct evsel *evsel,
> + pid_t pid, int cpu, int thread,
> + struct perf_cpu_map *cpus,
> + struct perf_thread_map *threads)
> +{
> + int fd, group_fd, rc;
> + struct perf_event_open_result res;
> +
> + if (!evsel->cgrp && !evsel->core.system_wide)
> + pid = perf_thread_map__pid(threads, thread);
> +
> + group_fd = get_group_fd(evsel, cpu, thread);
> +
> + test_attr__ready();
> +
> + pr_debug2_peo("sys_perf_event_open: pid %d cpu %d group_fd %d flags %#lx",
> + pid, cpus->map[cpu], group_fd, evsel->open_flags);
> +
> + fd = sys_perf_event_open(&evsel->core.attr, pid, cpus->map[cpu],
> + group_fd, evsel->open_flags);
> +
> + FD(evsel, cpu, thread) = fd;
> + res.fd = fd;
> +
> + if (fd < 0) {
> + rc = -errno;
> +
> + pr_debug2_peo("\nsys_perf_event_open failed, error %d\n",
> + rc);
> + res.rc = rc;
> + res.err = PEO_FALLBACK;
> + return res;
> + }
> +
> + bpf_counter__install_pe(evsel, cpu, fd);
> +
> + if (unlikely(test_attr__enabled)) {
> + test_attr__open(&evsel->core.attr, pid,
> + cpus->map[cpu], fd,
> + group_fd, evsel->open_flags);
> + }
> +
> + pr_debug2_peo(" = %d\n", fd);
> +
> + if (evsel->bpf_fd >= 0) {
> + int evt_fd = fd;
> + int bpf_fd = evsel->bpf_fd;
> +
> + rc = ioctl(evt_fd,
> + PERF_EVENT_IOC_SET_BPF,
> + bpf_fd);
> + if (rc && errno != EEXIST) {
> + pr_err("failed to attach bpf fd %d: %s\n",
> + bpf_fd, strerror(errno));
> + res.rc = -EINVAL;
> + res.err = PEO_ERROR;
> + return res;
> + }
> + }
> +
> + /*
> + * If we succeeded but had to kill clockid, fail and
> + * have evsel__open_strerror() print us a nice error.
> + */
> + if (perf_missing_features.clockid ||
> + perf_missing_features.clockid_wrong) {
> + res.rc = -EINVAL;
> + res.err = PEO_ERROR;
> + return res;
> + }
> +
> + res.rc = 0;
> + res.err = PEO_SUCCESS;
> + return res;
> +}
> +
> static int evsel__open_cpu(struct evsel *evsel, struct perf_cpu_map *cpus,
> struct perf_thread_map *threads,
> int start_cpu, int end_cpu)
> @@ -1952,6 +2028,7 @@ static int evsel__open_cpu(struct evsel *evsel, struct perf_cpu_map *cpus,
> int cpu, thread, nthreads;
> int pid = -1, err, old_errno;
> enum rlimit_action set_rlimit = NO_CHANGE;
> + struct perf_event_open_result peo_res;
>
> err = __evsel__prepare_open(evsel, cpus, threads);
> if (err)
> @@ -1979,67 +2056,22 @@ static int evsel__open_cpu(struct evsel *evsel, struct perf_cpu_map *cpus,
> for (cpu = start_cpu; cpu < end_cpu; cpu++) {
>
> for (thread = 0; thread < nthreads; thread++) {
> - int fd, group_fd;
> retry_open:
> if (thread >= nthreads)
> break;
>
> - if (!evsel->cgrp && !evsel->core.system_wide)
> - pid = perf_thread_map__pid(threads, thread);
> -
> - group_fd = get_group_fd(evsel, cpu, thread);
> -
> - test_attr__ready();
> -
> - pr_debug2_peo("sys_perf_event_open: pid %d cpu %d group_fd %d flags %#lx",
> - pid, cpus->map[cpu], group_fd, evsel->open_flags);
> + peo_res = perf_event_open(evsel, pid, cpu, thread, cpus,
> + threads);
>
> - fd = sys_perf_event_open(&evsel->core.attr, pid, cpus->map[cpu],
> - group_fd, evsel->open_flags);
> -
> - FD(evsel, cpu, thread) = fd;
> -
> - if (fd < 0) {
> - err = -errno;
> -
> - pr_debug2_peo("\nsys_perf_event_open failed, error %d\n",
> - err);
> + err = peo_res.rc;
> + switch (peo_res.err) {
> + case PEO_SUCCESS:
> + set_rlimit = NO_CHANGE;
> + continue;
> + case PEO_FALLBACK:
> goto try_fallback;
> - }
> -
> - bpf_counter__install_pe(evsel, cpu, fd);
> -
> - if (unlikely(test_attr__enabled)) {
> - test_attr__open(&evsel->core.attr, pid, cpus->map[cpu],
> - fd, group_fd, evsel->open_flags);
> - }
> -
> - pr_debug2_peo(" = %d\n", fd);
> -
> - if (evsel->bpf_fd >= 0) {
> - int evt_fd = fd;
> - int bpf_fd = evsel->bpf_fd;
> -
> - err = ioctl(evt_fd,
> - PERF_EVENT_IOC_SET_BPF,
> - bpf_fd);
> - if (err && errno != EEXIST) {
> - pr_err("failed to attach bpf fd %d: %s\n",
> - bpf_fd, strerror(errno));
> - err = -EINVAL;
> - goto out_close;
> - }
> - }
> -
> - set_rlimit = NO_CHANGE;
> -
> - /*
> - * If we succeeded but had to kill clockid, fail and
> - * have evsel__open_strerror() print us a nice error.
> - */
> - if (perf_missing_features.clockid ||
> - perf_missing_features.clockid_wrong) {
> - err = -EINVAL;
> + default:
> + case PEO_ERROR:
> goto out_close;
> }
> }
> diff --git a/tools/perf/util/evsel.h b/tools/perf/util/evsel.h
> index 0a245afab2d87d74..8c9827a93ac001a7 100644
> --- a/tools/perf/util/evsel.h
> +++ b/tools/perf/util/evsel.h
> @@ -282,6 +282,18 @@ int evsel__enable(struct evsel *evsel);
> int evsel__disable(struct evsel *evsel);
> int evsel__disable_cpu(struct evsel *evsel, int cpu);
>
> +enum perf_event_open_err {
> + PEO_SUCCESS,
> + PEO_FALLBACK,
> + PEO_ERROR
> +};
> +
> +struct perf_event_open_result {
> + enum perf_event_open_err err;
> + int rc;
> + int fd;
> +};
> +
> int evsel__open_per_cpu(struct evsel *evsel, struct perf_cpu_map *cpus, int cpu);
> int evsel__open_per_thread(struct evsel *evsel, struct perf_thread_map *threads);
> int evsel__open(struct evsel *evsel, struct perf_cpu_map *cpus,
> --
> 2.31.1
--
- Arnaldo
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