On 25/05/20 5:23 pm, Alexey Budankov wrote:
>
> Introduce --ctl-fd[-ack] options to pass open file descriptors numbers
> from command line. Extend perf-record.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-record.txt | 39 ++++++++++++++++++++++++
> tools/perf/builtin-record.c | 10 ++++++
> tools/perf/util/record.h | 2 ++
> 3 files changed, 51 insertions(+)
>
> diff --git a/tools/perf/Documentation/perf-record.txt
> b/tools/perf/Documentation/perf-record.txt
> index c2c4ce7ccee2..5c012cfe68a4 100644
> --- a/tools/perf/Documentation/perf-record.txt
> +++ b/tools/perf/Documentation/perf-record.txt
> @@ -614,6 +614,45 @@ appended unit character - B/K/M/G
> The number of threads to run when synthesizing events for existing
> processes.
> By default, the number of threads equals 1.
>
> +--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.
You should also explain the use of --delay=-1 here.
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 record -D -1 -e cpu-cycles -a \
> + --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 $?
> +
> +
> SEE ALSO
> --------
> linkperf:perf-stat[1], linkperf:perf-list[1], linkperf:perf-intel-pt[1]
> diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
> index 1ff3b7a77283..e057a2be42b7 100644
> --- a/tools/perf/builtin-record.c
> +++ b/tools/perf/builtin-record.c
> @@ -1761,6 +1761,9 @@ static int __cmd_record(struct record *rec, int argc,
> const char **argv)
> perf_evlist__start_workload(rec->evlist);
> }
>
> + if (evlist__initialize_ctlfd(rec->evlist, opts->ctl_fd,
> opts->ctl_fd_ack))
> + goto out_child;
> +
> if (opts->initial_delay) {
> pr_info(EVLIST_DISABLED_MSG);
> if (opts->initial_delay > 0) {
> @@ -1907,6 +1910,7 @@ static int __cmd_record(struct record *rec, int argc,
> const char **argv)
> record__synthesize_workload(rec, true);
>
> out_child:
> + evlist__finalize_ctlfd(rec->evlist);
> record__mmap_read_all(rec, true);
> record__aio_mmap_read_sync(rec);
>
> @@ -2392,6 +2396,8 @@ static struct record record = {
> },
> .mmap_flush = MMAP_FLUSH_DEFAULT,
> .nr_threads_synthesize = 1,
> + .ctl_fd = -1,
> + .ctl_fd_ack = -1,
> },
> .tool = {
> .sample = process_sample_event,
> @@ -2587,6 +2593,10 @@ static struct option __record_options[] = {
> OPT_UINTEGER(0, "num-thread-synthesize",
> &record.opts.nr_threads_synthesize,
> "number of threads to run for event synthesis"),
> + OPT_INTEGER(0, "ctl-fd", &record.opts.ctl_fd,
> + "Listen on fd descriptor for command to control measurement
> ('enable': enable events, 'disable': disable events)"),
> + OPT_INTEGER(0, "ctl-fd-ack", &record.opts.ctl_fd_ack,
> + "Send control command completion ('ack') to fd ack
> descriptor"),
> OPT_END()
> };
>
> diff --git a/tools/perf/util/record.h b/tools/perf/util/record.h
> index 96a73bbd8cd4..da18aeca3623 100644
> --- a/tools/perf/util/record.h
> +++ b/tools/perf/util/record.h
> @@ -69,6 +69,8 @@ struct record_opts {
> int mmap_flush;
> unsigned int comp_level;
> unsigned int nr_threads_synthesize;
> + int ctl_fd;
> + int ctl_fd_ack;
> };
>
> extern const char * const *record_usage;
>
