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Message-ID: <20160524184030.GX8897@kernel.org> Date: Tue, 24 May 2016 15:40:30 -0300 From: Arnaldo Carvalho de Melo <acme@...nel.org> To: Wang Nan <wangnan0@...wei.com> Cc: pi3orama@....com, linux-kernel@...r.kernel.org, He Kuang <hekuang@...wei.com>, Arnaldo Carvalho de Melo <acme@...hat.com>, Jiri Olsa <jolsa@...nel.org>, Masami Hiramatsu <masami.hiramatsu.pt@...achi.com>, Namhyung Kim <namhyung@...nel.org>, Zefan Li <lizefan@...wei.com> Subject: Re: [PATCH v4 3/7] perf tools: Enable overwrite settings Em Tue, May 24, 2016 at 02:29:00AM +0000, Wang Nan escreveu: > This patch allows following config terms and option: > > Globally setting events to overwrite; > > # perf record --overwrite ... > > Set specific events to be overwrite or no-overwrite. > > # perf record --event cycles/overwrite/ ... > # perf record --event cycles/no-overwrite/ ... So, based on this chunk of documentation in this patch: <quote> Perf dumps data from overwritable ring buffer when switching output (see --switch-output) and before terminate. </> I tried: No --overwrite: # perf record -e syscalls:*enter_nanosleep* usleep 1 [ perf record: Woken up 1 times to write data ] [ perf record: Captured and wrote 0.019 MB perf.data (1 samples) ] # perf evlist -v syscalls:sys_enter_nanosleep: type: 2, size: 112, config: 0x132, { sample_period, sample_freq }: 1, sample_type: IP|TID|TIME|CPU|PERIOD|RAW, disabled: 1, inherit: 1, mmap: 1, comm: 1, enable_on_exec: 1, task: 1, sample_id_all: 1, exclude_guest: 1, mmap2: 1, comm_exec: 1 # Tip: use 'perf evlist --trace-fields' to show fields for tracepoint events # perf script usleep 29416 [002] 220099.782982: syscalls:sys_enter_nanosleep: rqtp: 0x7ffc21f73cc0, rmtp: 0x00000000 Now I went on to try this new --overwrite thing: # perf record --overwrite -e syscalls:*enter_nanosleep* usleep 1 [ perf record: Woken up 1 times to write data ] [ perf record: Captured and wrote 0.019 MB perf.data ] # perf evlist -v syscalls:sys_enter_nanosleep: type: 2, size: 112, config: 0x132, { sample_period, sample_freq }: 1, sample_type: IP|TID|TIME|CPU|PERIOD|RAW, disabled: 1, inherit: 1, mmap: 1, comm: 1, enable_on_exec: 1, task: 1, sample_id_all: 1, exclude_guest: 1, mmap2: 1, comm_exec: 1, write_backward: 1 # Tip: use 'perf evlist --trace-fields' to show fields for tracepoint events # perf script # So it hasn't recorded anything at anytime, i.e. I expected, based on the documentation provided, that it would get what was in its buffer, to be written, i.e. the single "syscalls:sys_enter_nanosleep" event that took place in that workload. So I'm now trying it together with --switch-output, but I just get one timestamp suffixed perf.data file, empty, without that event that I know took place. Care to ellaborate here? - Arnaldo > Add missing config terms and update config term array size because the > longest string length is changed. > > For overwritable events, automatically select attr.write_backward since > perf requires it to be backward for reading. > > Signed-off-by: Wang Nan <wangnan0@...wei.com> > Signed-off-by: He Kuang <hekuang@...wei.com> > Cc: Arnaldo Carvalho de Melo <acme@...hat.com> > Cc: Jiri Olsa <jolsa@...nel.org> > Cc: Masami Hiramatsu <masami.hiramatsu.pt@...achi.com> > Cc: Namhyung Kim <namhyung@...nel.org> > Cc: Zefan Li <lizefan@...wei.com> > Cc: pi3orama@....com > --- > tools/perf/Documentation/perf-record.txt | 14 ++++++++++++++ > tools/perf/builtin-record.c | 1 + > tools/perf/perf.h | 1 + > tools/perf/util/evsel.c | 12 ++++++++++++ > tools/perf/util/evsel.h | 2 ++ > tools/perf/util/parse-events.c | 20 ++++++++++++++++++-- > tools/perf/util/parse-events.h | 2 ++ > tools/perf/util/parse-events.l | 2 ++ > 8 files changed, 52 insertions(+), 2 deletions(-) > > diff --git a/tools/perf/Documentation/perf-record.txt b/tools/perf/Documentation/perf-record.txt > index 8dbee83..f5cb932 100644 > --- a/tools/perf/Documentation/perf-record.txt > +++ b/tools/perf/Documentation/perf-record.txt > @@ -360,6 +360,20 @@ particular perf.data snapshot should be kept or not. > > Implies --timestamp-filename, --no-buildid and --no-buildid-cache. > > +--overwrite:: > +Makes all events use overwritable ring buffer. Event with overwritable ring > +buffer works like a flight recorder: when buffer gets full, instead of dumping > +records into output file, kernel overwrites old records silently. Perf dumps > +data from overwritable ring buffer when switching output (see --switch-output) > +and before terminate. > + > +Perf behaves like a daemon when '--overwrite' and '--switch-output' are > +provided. It record and drop events in background, and dumps data when > +something unusual is detected. > + > +'overwrite' attribute can also be set or canceled for specific event using > +config terms like 'cycles/overwrite/' and 'instructions/no-overwrite/'. > + > SEE ALSO > -------- > linkperf:perf-stat[1], linkperf:perf-list[1] > diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c > index d4cf1b0..9611380 100644 > --- a/tools/perf/builtin-record.c > +++ b/tools/perf/builtin-record.c > @@ -1310,6 +1310,7 @@ struct option __record_options[] = { > OPT_BOOLEAN_SET('i', "no-inherit", &record.opts.no_inherit, > &record.opts.no_inherit_set, > "child tasks do not inherit counters"), > + OPT_BOOLEAN(0, "overwrite", &record.opts.overwrite, "use overwrite mode"), > OPT_UINTEGER('F', "freq", &record.opts.user_freq, "profile at this frequency"), > OPT_CALLBACK('m', "mmap-pages", &record.opts, "pages[,pages]", > "number of mmap data pages and AUX area tracing mmap pages", > diff --git a/tools/perf/perf.h b/tools/perf/perf.h > index cd8f1b1..608b42b 100644 > --- a/tools/perf/perf.h > +++ b/tools/perf/perf.h > @@ -59,6 +59,7 @@ struct record_opts { > bool record_switch_events; > bool all_kernel; > bool all_user; > + bool overwrite; > unsigned int freq; > unsigned int mmap_pages; > unsigned int auxtrace_mmap_pages; > diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c > index 02c177d..6330a4f 100644 > --- a/tools/perf/util/evsel.c > +++ b/tools/perf/util/evsel.c > @@ -671,11 +671,22 @@ static void apply_config_terms(struct perf_evsel *evsel, > */ > attr->inherit = term->val.inherit ? 1 : 0; > break; > + case PERF_EVSEL__CONFIG_TERM_OVERWRITE: > + evsel->overwrite = term->val.overwrite ? 1 : 0; > + break; > default: > break; > } > } > > + /* > + * Set backward after config term processing because it is > + * possible to set overwrite globally, without config > + * terms. > + */ > + if (evsel->overwrite) > + attr->write_backward = 1; > + > /* User explicitly set per-event callgraph, clear the old setting and reset. */ > if ((callgraph_buf != NULL) || (dump_size > 0)) { > > @@ -747,6 +758,7 @@ void perf_evsel__config(struct perf_evsel *evsel, struct record_opts *opts, > > attr->sample_id_all = perf_missing_features.sample_id_all ? 0 : 1; > attr->inherit = !opts->no_inherit; > + evsel->overwrite = opts->overwrite; > > perf_evsel__set_sample_bit(evsel, IP); > perf_evsel__set_sample_bit(evsel, TID); > diff --git a/tools/perf/util/evsel.h b/tools/perf/util/evsel.h > index c1f1015..bce99fa 100644 > --- a/tools/perf/util/evsel.h > +++ b/tools/perf/util/evsel.h > @@ -44,6 +44,7 @@ enum { > PERF_EVSEL__CONFIG_TERM_CALLGRAPH, > PERF_EVSEL__CONFIG_TERM_STACK_USER, > PERF_EVSEL__CONFIG_TERM_INHERIT, > + PERF_EVSEL__CONFIG_TERM_OVERWRITE, > PERF_EVSEL__CONFIG_TERM_MAX, > }; > > @@ -57,6 +58,7 @@ struct perf_evsel_config_term { > char *callgraph; > u64 stack_user; > bool inherit; > + bool overwrite; > } val; > }; > > diff --git a/tools/perf/util/parse-events.c b/tools/perf/util/parse-events.c > index bcbc983..85f813d 100644 > --- a/tools/perf/util/parse-events.c > +++ b/tools/perf/util/parse-events.c > @@ -900,6 +900,8 @@ static const char *config_term_names[__PARSE_EVENTS__TERM_TYPE_NR] = { > [PARSE_EVENTS__TERM_TYPE_STACKSIZE] = "stack-size", > [PARSE_EVENTS__TERM_TYPE_NOINHERIT] = "no-inherit", > [PARSE_EVENTS__TERM_TYPE_INHERIT] = "inherit", > + [PARSE_EVENTS__TERM_TYPE_OVERWRITE] = "overwrite", > + [PARSE_EVENTS__TERM_TYPE_NOOVERWRITE] = "no-overwrite", > }; > > static bool config_term_shrinked; > @@ -992,6 +994,12 @@ do { \ > case PARSE_EVENTS__TERM_TYPE_NOINHERIT: > CHECK_TYPE_VAL(NUM); > break; > + case PARSE_EVENTS__TERM_TYPE_OVERWRITE: > + CHECK_TYPE_VAL(NUM); > + break; > + case PARSE_EVENTS__TERM_TYPE_NOOVERWRITE: > + CHECK_TYPE_VAL(NUM); > + break; > case PARSE_EVENTS__TERM_TYPE_NAME: > CHECK_TYPE_VAL(STR); > break; > @@ -1040,6 +1048,8 @@ static int config_term_tracepoint(struct perf_event_attr *attr, > case PARSE_EVENTS__TERM_TYPE_STACKSIZE: > case PARSE_EVENTS__TERM_TYPE_INHERIT: > case PARSE_EVENTS__TERM_TYPE_NOINHERIT: > + case PARSE_EVENTS__TERM_TYPE_OVERWRITE: > + case PARSE_EVENTS__TERM_TYPE_NOOVERWRITE: > return config_term_common(attr, term, err); > default: > if (err) { > @@ -1109,6 +1119,12 @@ do { \ > case PARSE_EVENTS__TERM_TYPE_NOINHERIT: > ADD_CONFIG_TERM(INHERIT, inherit, term->val.num ? 0 : 1); > break; > + case PARSE_EVENTS__TERM_TYPE_OVERWRITE: > + ADD_CONFIG_TERM(OVERWRITE, overwrite, term->val.num ? 1 : 0); > + break; > + case PARSE_EVENTS__TERM_TYPE_NOOVERWRITE: > + ADD_CONFIG_TERM(OVERWRITE, overwrite, term->val.num ? 0 : 1); > + break; > default: > break; > } > @@ -2322,9 +2338,9 @@ static void config_terms_list(char *buf, size_t buf_sz) > char *parse_events_formats_error_string(char *additional_terms) > { > char *str; > - /* "branch_type" is the longest name */ > + /* "no-overwrite" is the longest name */ > char static_terms[__PARSE_EVENTS__TERM_TYPE_NR * > - (sizeof("branch_type") - 1)]; > + (sizeof("no-overwrite") - 1)]; > > config_terms_list(static_terms, sizeof(static_terms)); > /* valid terms */ > diff --git a/tools/perf/util/parse-events.h b/tools/perf/util/parse-events.h > index d740c3c..f341d9d 100644 > --- a/tools/perf/util/parse-events.h > +++ b/tools/perf/util/parse-events.h > @@ -68,6 +68,8 @@ enum { > PARSE_EVENTS__TERM_TYPE_STACKSIZE, > PARSE_EVENTS__TERM_TYPE_NOINHERIT, > PARSE_EVENTS__TERM_TYPE_INHERIT, > + PARSE_EVENTS__TERM_TYPE_NOOVERWRITE, > + PARSE_EVENTS__TERM_TYPE_OVERWRITE, > __PARSE_EVENTS__TERM_TYPE_NR, > }; > > diff --git a/tools/perf/util/parse-events.l b/tools/perf/util/parse-events.l > index 1477fbc..cc4c426 100644 > --- a/tools/perf/util/parse-events.l > +++ b/tools/perf/util/parse-events.l > @@ -201,6 +201,8 @@ call-graph { return term(yyscanner, PARSE_EVENTS__TERM_TYPE_CALLGRAPH); } > stack-size { return term(yyscanner, PARSE_EVENTS__TERM_TYPE_STACKSIZE); } > inherit { return term(yyscanner, PARSE_EVENTS__TERM_TYPE_INHERIT); } > no-inherit { return term(yyscanner, PARSE_EVENTS__TERM_TYPE_NOINHERIT); } > +overwrite { return term(yyscanner, PARSE_EVENTS__TERM_TYPE_OVERWRITE); } > +no-overwrite { return term(yyscanner, PARSE_EVENTS__TERM_TYPE_NOOVERWRITE); } > , { return ','; } > "/" { BEGIN(INITIAL); return '/'; } > {name_minus} { return str(yyscanner, PE_NAME); } > -- > 1.8.3.4
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