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Subject[PATCH v7 11/20] perf record: Document parallel data streaming mode
Date
Document --threads option syntax and parallel data streaming modes
in Documentation/perf-record.txt. Implement compatibility checks for
other modes and related command line options: asynchronous(--aio)
trace streaming and affinity (--affinity) modes, pipe mode, AUX
area tracing --snapshot and --aux-sample options, --switch-output,
--switch-output-event, --switch-max-files and --timestamp-filename
options. Parallel data streaming is compatible with Zstd compression
(--compression-level) and external control commands (--control).
Cpu mask provided via -C option filters --threads specification masks.

Signed-off-by: Alexey Bayduraev <alexey.v.bayduraev@linux.intel.com>
---
tools/perf/Documentation/perf-record.txt | 30 +++++++++++++++
tools/perf/builtin-record.c | 49 ++++++++++++++++++++++--
2 files changed, 76 insertions(+), 3 deletions(-)

diff --git a/tools/perf/Documentation/perf-record.txt b/tools/perf/Documentation/perf-record.txt
index d71bac847936..2046b28d9822 100644
--- a/tools/perf/Documentation/perf-record.txt
+++ b/tools/perf/Documentation/perf-record.txt
@@ -695,6 +695,36 @@ measurements:
wait -n ${perf_pid}
exit $?

+--threads=<spec>::
+Write collected trace data into several data files using parallel threads.
+<spec> value can be user defined list of masks. Masks separated by colon
+define cpus to be monitored by a thread and affinity mask of that thread
+is separated by slash:
+
+ <cpus mask 1>/<affinity mask 1>:<cpus mask 2>/<affinity mask 2>:...
+
+For example user specification like the following:
+
+ 0,2-4/2-4:1,5-7/5-7
+
+specifies parallel threads layout that consists of two threads,
+the first thread monitors cpus 0 and 2-4 with the affinity mask 2-4,
+the second monitors cpus 1 and 5-7 with the affinity mask 5-7.
+
+<spec> value can also be a string meaning predefined parallel threads
+layout:
+
+ cpu - create new data streaming thread for every monitored cpu
+ core - create new thread to monitor cpus grouped by a core
+ socket - create new thread to monitor cpus grouped by a socket
+ numa - create new threed to monitor cpus grouped by a numa domain
+
+Predefined layouts can be used on systems with large number of cpus in
+order not to spawn multiple per-cpu streaming threads but still avoid LOST
+events in data directory files. Option specified with no or empty value
+defaults to cpu layout. Masks defined or provided by the option value are
+filtered through the mask provided by -C option.
+
include::intel-hybrid.txt[]

SEE ALSO
diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
index ce3b374d22ea..a0ad4dd074ca 100644
--- a/tools/perf/builtin-record.c
+++ b/tools/perf/builtin-record.c
@@ -800,6 +800,12 @@ static int record__auxtrace_init(struct record *rec)
{
int err;

+ if ((rec->opts.auxtrace_snapshot_opts || rec->opts.auxtrace_sample_opts)
+ && record__threads_enabled(rec)) {
+ pr_err("AUX area tracing options are not available in parallel streaming mode.\n");
+ return -EINVAL;
+ }
+
if (!rec->itr) {
rec->itr = auxtrace_record__init(rec->evlist, &err);
if (err)
@@ -2154,6 +2160,17 @@ static int __cmd_record(struct record *rec, int argc, const char **argv)
return PTR_ERR(session);
}

+ if (record__threads_enabled(rec)) {
+ if (perf_data__is_pipe(&rec->data)) {
+ pr_err("Parallel trace streaming is not available in pipe mode.\n");
+ return -1;
+ }
+ if (rec->opts.full_auxtrace) {
+ pr_err("Parallel trace streaming is not available in AUX area tracing mode.\n");
+ return -1;
+ }
+ }
+
fd = perf_data__fd(data);
rec->session = session;

@@ -2922,12 +2939,22 @@ static int switch_output_setup(struct record *rec)
* --switch-output=signal, as we'll send a SIGUSR2 from the side band
* thread to its parent.
*/
- if (rec->switch_output_event_set)
+ if (rec->switch_output_event_set) {
+ if (record__threads_enabled(rec)) {
+ pr_warning("WARNING: --switch-output-event option is not available in parallel streaming mode.\n");
+ return 0;
+ }
goto do_signal;
+ }

if (!s->set)
return 0;

+ if (record__threads_enabled(rec)) {
+ pr_warning("WARNING: --switch-output option is not available in parallel streaming mode.\n");
+ return 0;
+ }
+
if (!strcmp(s->str, "signal")) {
do_signal:
s->signal = true;
@@ -3225,8 +3252,8 @@ static struct option __record_options[] = {
"Set affinity mask of trace reading thread to NUMA node cpu mask or cpu of processed mmap buffer",
record__parse_affinity),
#ifdef HAVE_ZSTD_SUPPORT
- OPT_CALLBACK_OPTARG('z', "compression-level", &record.opts, &comp_level_default,
- "n", "Compressed records using specified level (default: 1 - fastest compression, 22 - greatest compression)",
+ OPT_CALLBACK_OPTARG('z', "compression-level", &record.opts, &comp_level_default, "n",
+ "Compress records using specified level (default: 1 - fastest compression, 22 - greatest compression)",
record__parse_comp_level),
#endif
OPT_CALLBACK(0, "max-size", &record.output_max_size,
@@ -3653,6 +3680,17 @@ int cmd_record(int argc, const char **argv)
if (rec->opts.kcore || record__threads_enabled(rec))
rec->data.is_dir = true;

+ if (record__threads_enabled(rec)) {
+ if (rec->opts.affinity != PERF_AFFINITY_SYS) {
+ pr_err("--affinity option is mutually exclusive to parallel streaming mode.\n");
+ goto out_opts;
+ }
+ if (record__aio_enabled(rec)) {
+ pr_err("Asynchronous streaming mode (--aio) is mutually exclusive to parallel streaming mode.\n");
+ goto out_opts;
+ }
+ }
+
if (rec->opts.comp_level != 0) {
pr_debug("Compression enabled, disabling build id collection at the end of the session.\n");
rec->no_buildid = true;
@@ -3686,6 +3724,11 @@ int cmd_record(int argc, const char **argv)
}
}

+ if (rec->timestamp_filename && record__threads_enabled(rec)) {
+ rec->timestamp_filename = false;
+ pr_warning("WARNING: --timestamp-filename option is not available in parallel streaming mode.\n");
+ }
+
/*
* Allow aliases to facilitate the lookup of symbols for address
* filters. Refer to auxtrace_parse_filters().
--
2.19.0
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