Provide --threads option in perf record command line interface. Threaded streaming mode mitigates profiling data losses and resolves scalability issues of serial and asynchronous (--aio) trace streaming modes on multicore server systems. The implementation is based on the prototype [1], [2] and the most closely relates to mode 3) "mode that creates thread for every monitored memory map".
Threaded streaming mode is available with Zstd compression/decompression (--compression-level) and handling of external commands (--control). AUX area tracing, related and derived modes like --snapshot or --aux-sample are not enabled. --switch-output, --switch-output-event, --switch-max-files and --timestamp-filename options are not enabled. Threaded trace streaming is not enabled for pipe mode. Asynchronous (--aio) trace streaming and affinity (--affinity) modes are mutually exclusive to the exposed threaded streaming mode. [1] git clone https://git.kernel.org/pub/scm/linux/kernel/git/jolsa/perf.git -b perf/record_threads [2] https://lore.kernel.org/lkml/20180913125450.21342-1-jo...@kernel.org/ Signed-off-by: Alexey Budankov <alexey.budan...@linux.intel.com> --- tools/perf/Documentation/perf-record.txt | 7 ++++ tools/perf/builtin-record.c | 45 +++++++++++++++++++++--- 2 files changed, 48 insertions(+), 4 deletions(-) diff --git a/tools/perf/Documentation/perf-record.txt b/tools/perf/Documentation/perf-record.txt index 768888b9326a..d8fa387da973 100644 --- a/tools/perf/Documentation/perf-record.txt +++ b/tools/perf/Documentation/perf-record.txt @@ -671,6 +671,13 @@ Example of bash shell script to enable and disable events during measurements: wait -n ${perf_pid} exit $? +--threads:: +Write collected trace data into per-CPU trace files using parallel threads. +List of monitored CPUs can be configured by a mask provided via --cpu option. +Trace writing threads correspond one-to-one to mapped data buffers. Threads +and buffers are affined to monitored CPUs and NUMA nodes according to system +topology. Threaded trace streaming mode is mutually exclusive to asynchronous +trace streaming (--aio) and affinity (--affinity) modes. SEE ALSO -------- diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c index 1d41e996a994..575b0b595081 100644 --- a/tools/perf/builtin-record.c +++ b/tools/perf/builtin-record.c @@ -780,6 +780,12 @@ 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 threaded streaming mode.\n"); + return -EINVAL; + } + if (!rec->itr) { rec->itr = auxtrace_record__init(rec->evlist, &err); if (err) @@ -2008,6 +2014,11 @@ static int __cmd_record(struct record *rec, int argc, const char **argv) return PTR_ERR(session); } + if (record__threads_enabled(rec) && perf_data__is_pipe(&rec->data)) { + pr_err("Threaded trace streaming is not available in pipe mode.\n"); + return -1; + } + fd = perf_data__fd(data); rec->session = session; @@ -2680,12 +2691,22 @@ 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 threaded 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 threaded streaming mode.\n"); + return 0; + } + if (!strcmp(s->str, "signal")) { do_signal: s->signal = true; @@ -2964,8 +2985,8 @@ 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, @@ -2984,6 +3005,8 @@ static struct option __record_options[] = { "\t\t\t Optionally send control command completion ('ack\\n') to ack-fd descriptor.\n" "\t\t\t Alternatively, ctl-fifo / ack-fifo will be opened and used as ctl-fd / ack-fd.", parse_control_option), + OPT_BOOLEAN(0, "threads", &record.opts.threads, + "write collected trace data into per-CPU trace files using parallel threads"), OPT_END() }; @@ -3046,8 +3069,17 @@ 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 (record__threads_enabled(rec)) { + if (rec->opts.affinity != PERF_AFFINITY_SYS) { + pr_err("--affinity option is mutually exclusive to threaded streaming mode.\n"); + goto out_opts; + } rec->opts.affinity = PERF_AFFINITY_CPU; + if (record__aio_enabled(rec)) { + pr_err("Asynchronous streaming mode (--aio) is mutually exclusive to threaded 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"); @@ -3082,6 +3114,11 @@ 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 threaded streaming mode.\n"); + } + /* * Allow aliases to facilitate the lookup of symbols for address * filters. Refer to auxtrace_parse_filters(). -- 2.24.1
