Re: [PATCH V3 4/6] perf tools: Add FIFO file names as alternative options to --control

Adrian Hunter
2020-09-03T10:39:17Z

On 2/09/20 8:03 pm, Alexey Budankov wrote:
>
> On 02.09.2020 13:57, Adrian Hunter wrote:
>> Enable the --control option to accept file names as an alternative to
>> file descriptors.
>>
>> Example:
>>
>> $ mkfifo perf.control
>> $ mkfifo perf.ack
>> $ cat perf.ack &
>> [1] 6808
>> $ perf record --control fifo:perf.control,perf.ack -- sleep 300 &
>> [2] 6810
>> $ echo disable > perf.control
>> $ Events disabled
>> ack
>>
>> $ echo enable > perf.control
>> $ Events enabled
>> ack
>>
>> $ echo disable > perf.control
>> $ Events disabled
>> ack
>>
>> $ kill %2
>> [ perf record: Woken up 4 times to write data ]
>> $ [ perf record: Captured and wrote 0.018 MB perf.data (7 samples) ]
>>
>> [1]- Done cat perf.ack
>> [2]+ Terminated perf record --control fifo:perf.control,perf.ack -- sleep 300
>> $
>>
>> Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
>> Acked-by: Jiri Olsa <jolsa@redhat.com>
>> ---
>>
>>
>> Changes in V3:
>>
>> Rename evlist__parse_control_names to evlist__parse_control_fifo
>> Explicitly initialize *ctl_fd_close = false
>>
>>
>> tools/perf/Documentation/perf-record.txt | 2 +
>> tools/perf/Documentation/perf-stat.txt | 2 +
>> tools/perf/builtin-record.c | 34 +++++++++++----
>> tools/perf/builtin-stat.c | 18 ++++++--
>> tools/perf/util/evlist.c | 55 +++++++++++++++++++++++-
>> tools/perf/util/evlist.h | 2 +-
>> tools/perf/util/record.h | 1 +
>> tools/perf/util/stat.h | 1 +
>> 8 files changed, 101 insertions(+), 14 deletions(-)
>>
>> diff --git a/tools/perf/Documentation/perf-record.txt b/tools/perf/Documentation/perf-record.txt
>> index 07c4734f1c7a..2ffc1196d2b8 100644
>> --- a/tools/perf/Documentation/perf-record.txt
>> +++ b/tools/perf/Documentation/perf-record.txt
>> @@ -627,7 +627,9 @@ option. The -e option and this one can be mixed and matched. Events
>> can be grouped using the {} notation.
>> endif::HAVE_LIBPFM[]
>>
>> +--control=fifo:ctl-fifo[,ack-fifo]::
>> --control=fd:ctl-fd[,ack-fd]::
>> +ctl-fifo / ack-fifo are opened and used as ctl-fd / ack-fd as follows.
>> Listen on ctl-fd descriptor for command to control measurement ('enable': enable events,
>> 'disable': disable events). Measurements can be started with events disabled using
>> --delay=-1 option. Optionally send control command completion ('ack\n') to ack-fd descriptor
>> diff --git a/tools/perf/Documentation/perf-stat.txt b/tools/perf/Documentation/perf-stat.txt
>> index 7fb7368cc2d9..d33ffd11bb85 100644
>> --- a/tools/perf/Documentation/perf-stat.txt
>> +++ b/tools/perf/Documentation/perf-stat.txt
>> @@ -176,7 +176,9 @@ with it. --append may be used here. Examples:
>> 3>results perf stat --log-fd 3 -- $cmd
>> 3>>results perf stat --log-fd 3 --append -- $cmd
>>
>> +--control=fifo:ctl-fifo[,ack-fifo]::
>> --control=fd:ctl-fd[,ack-fd]::
>> +ctl-fifo / ack-fifo are opened and used as ctl-fd / ack-fd as follows.
>> Listen on ctl-fd descriptor for command to control measurement ('enable': enable events,
>> 'disable': disable events). Measurements can be started with events disabled using
>> --delay=-1 option. Optionally send control command completion ('ack\n') to ack-fd descriptor
>> diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
>> index f2ab5bd7e2ba..117dd180f780 100644
>> --- a/tools/perf/builtin-record.c
>> +++ b/tools/perf/builtin-record.c
>> @@ -2236,7 +2236,17 @@ static int parse_control_option(const struct option *opt,
>> {
>> struct record_opts *opts = opt->value;
>>
>> - return evlist__parse_control(str, &opts->ctl_fd, &opts->ctl_fd_ack);
>> + return evlist__parse_control(str, &opts->ctl_fd, &opts->ctl_fd_ack, &opts->ctl_fd_close);
>> +}
>> +
>> +static void close_control_option(struct record_opts *opts)
>
> This function above and the same one for stat mode below look duplicating.
> It could possibly be combined.

Good idea. I will send a separate patch for that though.

>
> Acked-by: Alexei Budankov <alexey.budankov@linux.intel.com>
>
> Regards,
> Alexei
>
>> +{
>> + if (opts->ctl_fd_close) {
>> + opts->ctl_fd_close = false;
>> + close(opts->ctl_fd);
>> + if (opts->ctl_fd_ack >= 0)
>> + close(opts->ctl_fd_ack);
>> + }
>> }
>>
>> static void switch_output_size_warn(struct record *rec)
>> @@ -2578,9 +2588,10 @@ static struct option __record_options[] = {
>> "libpfm4 event selector. use 'perf list' to list available events",
>> parse_libpfm_events_option),
>> #endif
>> - OPT_CALLBACK(0, "control", &record.opts, "fd:ctl-fd[,ack-fd]",
>> + OPT_CALLBACK(0, "control", &record.opts, "fd:ctl-fd[,ack-fd] or fifo:ctl-fifo[,ack-fifo]",
>> "Listen on ctl-fd descriptor for command to control measurement ('enable': enable events, 'disable': disable events).\n"
>> - "\t\t\t Optionally send control command completion ('ack\\n') to ack-fd descriptor.",
>> + "\t\t\t Optionally send control command completion ('ack\\n') to ack-fd descriptor.\n"
>> + "\t\t\t Alternatively, ctl-fifo / ack-fifo will be opened and used as ctl-fd / ack-fd.",
>> parse_control_option),
>> OPT_END()
>> };
>> @@ -2653,12 +2664,14 @@ int cmd_record(int argc, const char **argv)
>> !perf_can_record_switch_events()) {
>> ui__error("kernel does not support recording context switch events\n");
>> parse_options_usage(record_usage, record_options, "switch-events", 0);
>> - return -EINVAL;
>> + err = -EINVAL;
>> + goto out_opts;
>> }
>>
>> if (switch_output_setup(rec)) {
>> parse_options_usage(record_usage, record_options, "switch-output", 0);
>> - return -EINVAL;
>> + err = -EINVAL;
>> + goto out_opts;
>> }
>>
>> if (rec->switch_output.time) {
>> @@ -2669,8 +2682,10 @@ int cmd_record(int argc, const char **argv)
>> if (rec->switch_output.num_files) {
>> rec->switch_output.filenames = calloc(sizeof(char *),
>> rec->switch_output.num_files);
>> - if (!rec->switch_output.filenames)
>> - return -EINVAL;
>> + if (!rec->switch_output.filenames) {
>> + err = -EINVAL;
>> + goto out_opts;
>> + }
>> }
>>
>> /*
>> @@ -2686,7 +2701,8 @@ int cmd_record(int argc, const char **argv)
>> rec->affinity_mask.bits = bitmap_alloc(rec->affinity_mask.nbits);
>> if (!rec->affinity_mask.bits) {
>> pr_err("Failed to allocate thread mask for %zd cpus\n", rec->affinity_mask.nbits);
>> - return -ENOMEM;
>> + err = -ENOMEM;
>> + goto out_opts;
>> }
>> pr_debug2("thread mask[%zd]: empty\n", rec->affinity_mask.nbits);
>> }
>> @@ -2817,6 +2833,8 @@ int cmd_record(int argc, const char **argv)
>> evlist__delete(rec->evlist);
>> symbol__exit();
>> auxtrace_record__free(rec->itr);
>> +out_opts:
>> + close_control_option(&rec->opts);
>> return err;
>> }
>>
>> diff --git a/tools/perf/builtin-stat.c b/tools/perf/builtin-stat.c
>> index 12ce5cf2b10e..6170226d44f9 100644
>> --- a/tools/perf/builtin-stat.c
>> +++ b/tools/perf/builtin-stat.c
>> @@ -1047,7 +1047,17 @@ static int parse_control_option(const struct option *opt,
>> {
>> struct perf_stat_config *config = opt->value;
>>
>> - return evlist__parse_control(str, &config->ctl_fd, &config->ctl_fd_ack);
>> + return evlist__parse_control(str, &config->ctl_fd, &config->ctl_fd_ack, &config->ctl_fd_close);
>> +}
>> +
>> +static void close_control_option(struct perf_stat_config *config)
>> +{
>> + if (config->ctl_fd_close) {
>> + config->ctl_fd_close = false;
>> + close(config->ctl_fd);
>> + if (config->ctl_fd_ack >= 0)
>> + close(config->ctl_fd_ack);
>> + }
>> }
>>
>> static struct option stat_options[] = {
>> @@ -1151,9 +1161,10 @@ static struct option stat_options[] = {
>> "libpfm4 event selector. use 'perf list' to list available events",
>> parse_libpfm_events_option),
>> #endif
>> - OPT_CALLBACK(0, "control", &stat_config, "fd:ctl-fd[,ack-fd]",
>> + OPT_CALLBACK(0, "control", &stat_config, "fd:ctl-fd[,ack-fd] or fifo:ctl-fifo[,ack-fifo]",
>> "Listen on ctl-fd descriptor for command to control measurement ('enable': enable events, 'disable': disable events).\n"
>> - "\t\t\t Optionally send control command completion ('ack\\n') to ack-fd descriptor.",
>> + "\t\t\t Optionally send control command completion ('ack\\n') to ack-fd descriptor.\n"
>> + "\t\t\t Alternatively, ctl-fifo / ack-fifo will be opened and used as ctl-fd / ack-fd.",
>> parse_control_option),
>> OPT_END()
>> };
>> @@ -2396,6 +2407,7 @@ int cmd_stat(int argc, const char **argv)
>>
>> metricgroup__rblist_exit(&stat_config.metric_events);
>> runtime_stat_delete(&stat_config);
>> + close_control_option(&stat_config);
>>
>> return status;
>> }
>> diff --git a/tools/perf/util/evlist.c b/tools/perf/util/evlist.c
>> index 47d1045a19af..00593e5f2a9d 100644
>> --- a/tools/perf/util/evlist.c
>> +++ b/tools/perf/util/evlist.c
>> @@ -1727,12 +1727,63 @@ struct evsel *perf_evlist__reset_weak_group(struct evlist *evsel_list,
>> return leader;
>> }
>>
>> -int evlist__parse_control(const char *str, int *ctl_fd, int *ctl_fd_ack)
>> +static int evlist__parse_control_fifo(const char *str, int *ctl_fd, int *ctl_fd_ack, bool *ctl_fd_close)
>> +{
>> + char *s, *p;
>> + int ret = 0, fd;
>> +
>> + if (strncmp(str, "fifo:", 5))
>> + return -EINVAL;
>> +
>> + str += 5;
>> + if (!*str || *str == ',')
>> + return -EINVAL;
>> +
>> + s = strdup(str);
>> + if (!s)
>> + return -ENOMEM;
>> +
>> + p = strchr(s, ',');
>> + if (p)
>> + *p = '\0';
>> +
>> + /*
>> + * O_RDWR avoids POLLHUPs which is necessary to allow the other
>> + * end of a FIFO to be repeatedly opened and closed.
>> + */
>> + fd = open(s, O_RDWR | O_NONBLOCK | O_CLOEXEC);
>> + if (fd < 0) {
>> + pr_err("Failed to open '%s'\n", s);
>> + ret = -errno;
>> + goto out_free;
>> + }
>> + *ctl_fd = fd;
>> + *ctl_fd_close = true;
>> +
>> + if (p && *++p) {
>> + /* O_RDWR | O_NONBLOCK means the other end need not be open */
>> + fd = open(p, O_RDWR | O_NONBLOCK | O_CLOEXEC);
>> + if (fd < 0) {
>> + pr_err("Failed to open '%s'\n", p);
>> + ret = -errno;
>> + goto out_free;
>> + }
>> + *ctl_fd_ack = fd;
>> + }
>> +
>> +out_free:
>> + free(s);
>> + return ret;
>> +}
>> +
>> +int evlist__parse_control(const char *str, int *ctl_fd, int *ctl_fd_ack, bool *ctl_fd_close)
>> {
>> char *comma = NULL, *endptr = NULL;
>>
>> + *ctl_fd_close = false;
>> +
>> if (strncmp(str, "fd:", 3))
>> - return -EINVAL;
>> + return evlist__parse_control_fifo(str, ctl_fd, ctl_fd_ack, ctl_fd_close);
>>
>> *ctl_fd = strtoul(&str[3], &endptr, 0);
>> if (endptr == &str[3])
>> diff --git a/tools/perf/util/evlist.h b/tools/perf/util/evlist.h
>> index a5a5a07d5c55..a5678eb5ee60 100644
>> --- a/tools/perf/util/evlist.h
>> +++ b/tools/perf/util/evlist.h
>> @@ -373,7 +373,7 @@ enum evlist_ctl_cmd {
>> EVLIST_CTL_CMD_ACK
>> };
>>
>> -int evlist__parse_control(const char *str, int *ctl_fd, int *ctl_fd_ack);
>> +int evlist__parse_control(const char *str, int *ctl_fd, int *ctl_fd_ack, bool *ctl_fd_close);
>> int evlist__initialize_ctlfd(struct evlist *evlist, int ctl_fd, int ctl_fd_ack);
>> int evlist__finalize_ctlfd(struct evlist *evlist);
>> bool evlist__ctlfd_initialized(struct evlist *evlist);
>> diff --git a/tools/perf/util/record.h b/tools/perf/util/record.h
>> index 03678ff25539..266760ac9143 100644
>> --- a/tools/perf/util/record.h
>> +++ b/tools/perf/util/record.h
>> @@ -73,6 +73,7 @@ struct record_opts {
>> unsigned int nr_threads_synthesize;
>> int ctl_fd;
>> int ctl_fd_ack;
>> + bool ctl_fd_close;
>> };
>>
>> extern const char * const *record_usage;
>> diff --git a/tools/perf/util/stat.h b/tools/perf/util/stat.h
>> index f8778cffd941..65402e13b704 100644
>> --- a/tools/perf/util/stat.h
>> +++ b/tools/perf/util/stat.h
>> @@ -135,6 +135,7 @@ struct perf_stat_config {
>> struct rblist metric_events;
>> int ctl_fd;
>> int ctl_fd_ack;
>> + bool ctl_fd_close;
>> };
>>
>> void perf_stat__set_big_num(int set);
>>