On Wed, May 13, 2020 at 11:03:03AM +0300, Alexey Budankov wrote:
>
> Introduce --ctl-fd[-ack] options to pass open file descriptors numbers
> from command line. Extend perf-stat.txt file with --ctl-fd[-ack] options
> description. Document possible usage model introduced by --ctl-fd[-ack]
> options by providing example bash shell script.
>
> Signed-off-by: Alexey Budankov <alexey.budan...@linux.intel.com>
> ---
> tools/perf/Documentation/perf-stat.txt | 40 ++++++++++++++++++++++++++
> tools/perf/builtin-stat.c | 10 +++++++
> tools/perf/util/stat.h | 2 ++
> 3 files changed, 52 insertions(+)
>
> diff --git a/tools/perf/Documentation/perf-stat.txt
> b/tools/perf/Documentation/perf-stat.txt
> index 3b91b30d7672..7f7a0019fbfc 100644
> --- a/tools/perf/Documentation/perf-stat.txt
> +++ b/tools/perf/Documentation/perf-stat.txt
> @@ -164,6 +164,46 @@ with it. --append may be used here. Examples:
> 3>results perf stat --log-fd 3 -- $cmd
> 3>>results perf stat --log-fd 3 --append -- $cmd
>
> +--ctl-fd::
> +--ctl-fd-ack::
> +
> +Listen on ctl-fd descriptor for command to control measurement ('enable':
> enable events,
> +'disable': disable events). Optionally send control command completion
> ('ack') to fd-ack
> +descriptor to synchronize with the controlling process. Example of bash
> shell script
> +to enable and disable events during measurements:
> +
> +#!/bin/bash
> +
> +ctl_dir=/tmp/
> +
> +ctl_fifo=${ctl_dir}perf_ctl.fifo
> +test -p ${ctl_fifo} && unlink ${ctl_fifo}
> +mkfifo ${ctl_fifo}
> +exec {ctl_fd}<>${ctl_fifo}
> +
> +ctl_ack_fifo=${ctl_dir}perf_ctl_ack.fifo
> +test -p ${ctl_ack_fifo} && unlink ${ctl_ack_fifo}
> +mkfifo ${ctl_ack_fifo}
> +exec {ctl_fd_ack}<>${ctl_ack_fifo}
> +
> +perf stat -D -1 -e cpu-cycles -a -I 1000 \
> + --ctl-fd ${ctl_fd} --ctl-fd-ack ${ctl_fd_ack} \
> + -- sleep 30 &
> +perf_pid=$!
> +
> +sleep 5 && echo 'enable' >&${ctl_fd} && read -u ${ctl_fd_ack} e1 && echo
> "enabled(${e1})"
> +sleep 10 && echo 'disable' >&${ctl_fd} && read -u ${ctl_fd_ack} d1 && echo
> "disabled(${d1})"
> +
> +exec {ctl_fd_ack}>&-
> +unlink ${ctl_ack_fifo}
> +
> +exec {ctl_fd}>&-
> +unlink ${ctl_fifo}
> +
> +wait -n ${perf_pid}
> +exit $?
> +
> +
> --pre::
> --post::
> Pre and post measurement hooks, e.g.:
> diff --git a/tools/perf/builtin-stat.c b/tools/perf/builtin-stat.c
> index abea82a1ba24..88055aaf670f 100644
> --- a/tools/perf/builtin-stat.c
> +++ b/tools/perf/builtin-stat.c
> @@ -187,6 +187,8 @@ static struct perf_stat_config stat_config = {
> .metric_only_len = METRIC_ONLY_LEN,
> .walltime_nsecs_stats = &walltime_nsecs_stats,
> .big_num = true,
> + .ctl_fd = -1,
> + .ctl_fd_ack = -1
> };
>
> static inline void diff_timespec(struct timespec *r, struct timespec *a,
> @@ -984,6 +986,10 @@ static struct option stat_options[] = {
> "Use with 'percore' event qualifier to show the event "
> "counts of one hardware thread by sum up total hardware "
> "threads of same physical core"),
> + OPT_INTEGER(0, "ctl-fd", &stat_config.ctl_fd,
> + "Listen on fd descriptor for command to control measurement
> ('enable': enable events, 'disable': disable events)"),
> + OPT_INTEGER(0, "ctl-fd-ack", &stat_config.ctl_fd_ack,
> + "Send control command completion ('ack') to fd ack
> descriptor"),
> OPT_END()
> };
>
> @@ -2180,6 +2186,8 @@ int cmd_stat(int argc, const char **argv)
> signal(SIGALRM, skip_signal);
> signal(SIGABRT, skip_signal);
>
> + evlist__initialize_ctlfd(evsel_list, stat_config.ctl_fd,
> stat_config.ctl_fd_ack);
please check the return value
jirka
> +
> status = 0;
> for (run_idx = 0; forever || run_idx < stat_config.run_count;
> run_idx++) {
> if (stat_config.run_count != 1 && verbose > 0)
> @@ -2199,6 +2207,8 @@ int cmd_stat(int argc, const char **argv)
> if (!forever && status != -1 && !interval)
> print_counters(NULL, argc, argv);
>
> + evlist__finalize_ctlfd(evsel_list);
> +
> if (STAT_RECORD) {
> /*
> * We synthesize the kernel mmap record just so that older tools
> diff --git a/tools/perf/util/stat.h b/tools/perf/util/stat.h
> index 027b9dcd902f..0b0fa3a2cde2 100644
> --- a/tools/perf/util/stat.h
> +++ b/tools/perf/util/stat.h
> @@ -130,6 +130,8 @@ struct perf_stat_config {
> struct perf_cpu_map *cpus_aggr_map;
> u64 *walltime_run;
> struct rblist metric_events;
> + int ctl_fd;
> + int ctl_fd_ack;
> };
>
> void update_stats(struct stats *stats, u64 val);
> --
> 2.24.1
>
>
