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 | 40 ++++++++++++++++++++++++
tools/perf/builtin-record.c | 10 ++++++
tools/perf/util/record.h | 2 ++
3 files changed, 52 insertions(+)
diff --git a/tools/perf/Documentation/perf-record.txt
b/tools/perf/Documentation/perf-record.txt
index a84376605805..b0e9b7a1761e 100644
--- a/tools/perf/Documentation/perf-record.txt
+++ b/tools/perf/Documentation/perf-record.txt
@@ -627,6 +627,46 @@ option. The -e option and this one can be mixed and
matched. Events
can be grouped using the {} notation.
endif::HAVE_LIBPFM[]
+--ctl-fd::
+--ctl-fd-ack::
+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
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 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 0394e068dde8..8494ce964738 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);
@@ -2380,6 +2384,8 @@ 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 +2587,10 @@ static struct option __record_options[] = {
"libpfm4 event selector. use 'perf list' to list available
events",
parse_libpfm_events_option),
#endif
+ 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 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
