Introduce --control fd:ctl-fd[,ack-fd] options to pass open file descriptors numbers from command line. Extend perf-record.txt file with --control fd:ctl-fd[,ack-fd] options description. Document possible usage model introduced by --control fd:ctl-fd[,ack-fd] options by providing example bash shell script.
Signed-off-by: Alexey Budankov <alexey.budan...@linux.intel.com> Acked-by: Jiri Olsa <jo...@redhat.com> Acked-by: Namhyung Kim <namhy...@kernel.org> --- tools/perf/Documentation/perf-record.txt | 39 ++++++++++++++++++++++++ tools/perf/builtin-record.c | 37 ++++++++++++++++++++++ tools/perf/util/record.h | 2 ++ 3 files changed, 78 insertions(+) diff --git a/tools/perf/Documentation/perf-record.txt b/tools/perf/Documentation/perf-record.txt index a84376605805..3f72d8e261f3 100644 --- a/tools/perf/Documentation/perf-record.txt +++ b/tools/perf/Documentation/perf-record.txt @@ -627,6 +627,45 @@ option. The -e option and this one can be mixed and matched. Events can be grouped using the {} notation. endif::HAVE_LIBPFM[] +--control fd:ctl-fd[,ack-fd] +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 +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 record -D -1 -e cpu-cycles -a \ + --control fd:${ctl_fd},${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 632e61fe70bd..0718aa71b4ba 100644 --- a/tools/perf/builtin-record.c +++ b/tools/perf/builtin-record.c @@ -1749,6 +1749,9 @@ 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) { @@ -1895,6 +1898,7 @@ 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); @@ -2244,6 +2248,33 @@ static int record__parse_mmap_pages(const struct option *opt, return ret; } +static int parse_control_option(const struct option *opt, + const char *str, + int unset __maybe_unused) +{ + char *comma = NULL, *endptr = NULL; + struct record_opts *config = (struct record_opts *)opt->value; + + if (strncmp(str, "fd:", 3)) + return -EINVAL; + + config->ctl_fd = strtoul(&str[3], &endptr, 0); + if (endptr == &str[3]) + return -EINVAL; + + comma = strchr(str, ','); + if (comma) { + if (endptr != comma) + return -EINVAL; + + config->ctl_fd_ack = strtoul(comma + 1, &endptr, 0); + if (endptr == comma + 1 || *endptr != '\0') + return -EINVAL; + } + + return 0; +} + static void switch_output_size_warn(struct record *rec) { u64 wakeup_size = evlist__mmap_size(rec->opts.mmap_pages); @@ -2380,6 +2411,8 @@ 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, @@ -2581,6 +2614,10 @@ 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]", + "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.", + parse_control_option), OPT_END() }; diff --git a/tools/perf/util/record.h b/tools/perf/util/record.h index da138dcb4d34..4cb72a478af1 100644 --- a/tools/perf/util/record.h +++ b/tools/perf/util/record.h @@ -70,6 +70,8 @@ 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; -- 2.24.1