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Date: Wed, 1 Nov 2017 13:26:37 +0000 From: "Liang, Kan" <kan.liang@...el.com> To: Wang Nan <wangnan0@...wei.com>, "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>, "acme@...nel.org" <acme@...nel.org>, "jolsa@...hat.com" <jolsa@...hat.com>, "namhyung@...nel.org" <namhyung@...nel.org> Subject: RE: [PATCH 2/2] perf record: Replace 'overwrite' by 'flightrecorder' for better naming > The meaning of perf record's "overwrite" option and many "overwrite" in > source code are not clear. In perf's code, the 'overwrite' has 2 meanings: > 1. Make ringbuffer readonly (perf_evlist__mmap_ex's argument). > 2. Set evsel's "backward" attribute (in apply_config_terms). > > perf record doesn't use meaning 1 at all, but have a overwrite option, its > real meaning is setting backward. > I don't understand here. 'overwrite' has 2 meanings. perf record only support 1. It should be a bug, and need to be fixed. Why do we need a new mode? I think a new mode just make the codes more complex. Thanks, Kan > This patch separates these two concepts, introduce 'flightrecorder' mode > which is what we really want. It combines these 2 concept together, wraps > them into a record mode. In flight recorder mode, perf only dumps data > before > something happen. > > Signed-off-by: Wang Nan <wangnan0@...wei.com> > --- > tools/perf/Documentation/perf-record.txt | 8 ++++---- > tools/perf/builtin-record.c | 4 ++-- > tools/perf/perf.h | 2 +- > tools/perf/util/evsel.c | 6 +++--- > tools/perf/util/evsel.h | 4 ++-- > tools/perf/util/parse-events.c | 20 ++++++++++---------- > tools/perf/util/parse-events.h | 4 ++-- > tools/perf/util/parse-events.l | 4 ++-- > 8 files changed, 26 insertions(+), 26 deletions(-) > > diff --git a/tools/perf/Documentation/perf-record.txt > b/tools/perf/Documentation/perf-record.txt > index 5a626ef..463c2d3 100644 > --- a/tools/perf/Documentation/perf-record.txt > +++ b/tools/perf/Documentation/perf-record.txt > @@ -467,19 +467,19 @@ the beginning of record, collect them during > finalizing an output file. > The collected non-sample events reflects the status of the system when > record is finished. > > ---overwrite:: > +--flight-recorder:: > Makes all events use an overwritable ring buffer. An overwritable ring > buffer works like a flight recorder: when it gets full, the kernel will > overwrite the oldest records, that thus will never make it to the > perf.data file. > > -When '--overwrite' and '--switch-output' are used perf records and drops > +When '--flight-recorder' and '--switch-output' are used perf records and > drops > events until it receives a signal, meaning that something unusual was > detected that warrants taking a snapshot of the most current events, > those fitting in the ring buffer at that moment. > > -'overwrite' attribute can also be set or canceled for an event using > -config terms. For example: 'cycles/overwrite/' and 'instructions/no- > overwrite/'. > +'flightrecorder' attribute can also be set or canceled separately for an event > using > +config terms. For example: 'cycles/flightrecorder/' and 'instructions/no- > flightrecorder/'. > > Implies --tail-synthesize. > > diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c > index f4d9fc5..315ea09 100644 > --- a/tools/perf/builtin-record.c > +++ b/tools/perf/builtin-record.c > @@ -1489,7 +1489,7 @@ static struct option __record_options[] = { > "child tasks do not inherit counters"), > OPT_BOOLEAN(0, "tail-synthesize", &record.opts.tail_synthesize, > "synthesize non-sample events at the end of output"), > - OPT_BOOLEAN(0, "overwrite", &record.opts.overwrite, "use > overwrite mode"), > + OPT_BOOLEAN(0, "flight-recoder", &record.opts.flight_recorder, > "use flight recoder 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", > @@ -1733,7 +1733,7 @@ int cmd_record(int argc, const char **argv) > } > } > > - if (record.opts.overwrite) > + if (record.opts.flight_recorder) > record.opts.tail_synthesize = true; > > if (rec->evlist->nr_entries == 0 && > diff --git a/tools/perf/perf.h b/tools/perf/perf.h > index fbb0a9c..a7f7618 100644 > --- a/tools/perf/perf.h > +++ b/tools/perf/perf.h > @@ -57,7 +57,7 @@ struct record_opts { > bool all_kernel; > bool all_user; > bool tail_synthesize; > - bool overwrite; > + bool flight_recorder; > bool ignore_missing_thread; > unsigned int freq; > unsigned int mmap_pages; > diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c > index f894893..0e1e8e8 100644 > --- a/tools/perf/util/evsel.c > +++ b/tools/perf/util/evsel.c > @@ -772,8 +772,8 @@ static void apply_config_terms(struct perf_evsel > *evsel, > */ > attr->inherit = term->val.inherit ? 1 : 0; > break; > - case PERF_EVSEL__CONFIG_TERM_OVERWRITE: > - attr->write_backward = term->val.overwrite ? 1 : 0; > + case PERF_EVSEL__CONFIG_TERM_FLIGHTRECORDER: > + attr->write_backward = term->val.flightrecorder ? 1 : > 0; > break; > default: > break; > @@ -856,7 +856,7 @@ 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; > - attr->write_backward = opts->overwrite ? 1 : 0; > + attr->write_backward = opts->flight_recorder ? 1 : 0; > > 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 64782b1..115b637 100644 > --- a/tools/perf/util/evsel.h > +++ b/tools/perf/util/evsel.h > @@ -45,7 +45,7 @@ enum { > PERF_EVSEL__CONFIG_TERM_STACK_USER, > PERF_EVSEL__CONFIG_TERM_INHERIT, > PERF_EVSEL__CONFIG_TERM_MAX_STACK, > - PERF_EVSEL__CONFIG_TERM_OVERWRITE, > + PERF_EVSEL__CONFIG_TERM_FLIGHTRECORDER, > PERF_EVSEL__CONFIG_TERM_DRV_CFG, > PERF_EVSEL__CONFIG_TERM_BRANCH, > PERF_EVSEL__CONFIG_TERM_MAX, > @@ -63,7 +63,7 @@ struct perf_evsel_config_term { > u64 stack_user; > int max_stack; > bool inherit; > - bool overwrite; > + bool flightrecorder; > char *branch; > } val; > }; > diff --git a/tools/perf/util/parse-events.c b/tools/perf/util/parse-events.c > index 04f35db..61ae3d3 100644 > --- a/tools/perf/util/parse-events.c > +++ b/tools/perf/util/parse-events.c > @@ -914,8 +914,8 @@ static const char > *config_term_names[__PARSE_EVENTS__TERM_TYPE_NR] = { > [PARSE_EVENTS__TERM_TYPE_NOINHERIT] = "no-inherit", > [PARSE_EVENTS__TERM_TYPE_INHERIT] = "inherit", > [PARSE_EVENTS__TERM_TYPE_MAX_STACK] = "max-stack", > - [PARSE_EVENTS__TERM_TYPE_OVERWRITE] = "overwrite", > - [PARSE_EVENTS__TERM_TYPE_NOOVERWRITE] = "no- > overwrite", > + [PARSE_EVENTS__TERM_TYPE_FLIGHTRECORDER] = > "flightrecorder", > + [PARSE_EVENTS__TERM_TYPE_NOFLIGHTRECORDER] = "no- > flightrecorder", > [PARSE_EVENTS__TERM_TYPE_DRV_CFG] = "driver- > config", > }; > > @@ -1013,10 +1013,10 @@ do { > \ > case PARSE_EVENTS__TERM_TYPE_NOINHERIT: > CHECK_TYPE_VAL(NUM); > break; > - case PARSE_EVENTS__TERM_TYPE_OVERWRITE: > + case PARSE_EVENTS__TERM_TYPE_FLIGHTRECORDER: > CHECK_TYPE_VAL(NUM); > break; > - case PARSE_EVENTS__TERM_TYPE_NOOVERWRITE: > + case PARSE_EVENTS__TERM_TYPE_NOFLIGHTRECORDER: > CHECK_TYPE_VAL(NUM); > break; > case PARSE_EVENTS__TERM_TYPE_NAME: > @@ -1072,8 +1072,8 @@ static int config_term_tracepoint(struct > perf_event_attr *attr, > case PARSE_EVENTS__TERM_TYPE_INHERIT: > case PARSE_EVENTS__TERM_TYPE_NOINHERIT: > case PARSE_EVENTS__TERM_TYPE_MAX_STACK: > - case PARSE_EVENTS__TERM_TYPE_OVERWRITE: > - case PARSE_EVENTS__TERM_TYPE_NOOVERWRITE: > + case PARSE_EVENTS__TERM_TYPE_FLIGHTRECORDER: > + case PARSE_EVENTS__TERM_TYPE_NOFLIGHTRECORDER: > return config_term_common(attr, term, err); > default: > if (err) { > @@ -1149,11 +1149,11 @@ do { > \ > case PARSE_EVENTS__TERM_TYPE_MAX_STACK: > ADD_CONFIG_TERM(MAX_STACK, max_stack, term- > >val.num); > break; > - case PARSE_EVENTS__TERM_TYPE_OVERWRITE: > - ADD_CONFIG_TERM(OVERWRITE, overwrite, term- > >val.num ? 1 : 0); > + case PARSE_EVENTS__TERM_TYPE_FLIGHTRECORDER: > + ADD_CONFIG_TERM(FLIGHTRECORDER, > flightrecorder, term->val.num ? 1 : 0); > break; > - case PARSE_EVENTS__TERM_TYPE_NOOVERWRITE: > - ADD_CONFIG_TERM(OVERWRITE, overwrite, term- > >val.num ? 0 : 1); > + case PARSE_EVENTS__TERM_TYPE_NOFLIGHTRECORDER: > + ADD_CONFIG_TERM(FLIGHTRECORDER, > flightrecorder, term->val.num ? 0 : 1); > break; > case PARSE_EVENTS__TERM_TYPE_DRV_CFG: > ADD_CONFIG_TERM(DRV_CFG, drv_cfg, term- > >val.str); > diff --git a/tools/perf/util/parse-events.h b/tools/perf/util/parse-events.h > index 3909ca0..cd0b4eae 100644 > --- a/tools/perf/util/parse-events.h > +++ b/tools/perf/util/parse-events.h > @@ -70,8 +70,8 @@ enum { > PARSE_EVENTS__TERM_TYPE_NOINHERIT, > PARSE_EVENTS__TERM_TYPE_INHERIT, > PARSE_EVENTS__TERM_TYPE_MAX_STACK, > - PARSE_EVENTS__TERM_TYPE_NOOVERWRITE, > - PARSE_EVENTS__TERM_TYPE_OVERWRITE, > + PARSE_EVENTS__TERM_TYPE_NOFLIGHTRECORDER, > + PARSE_EVENTS__TERM_TYPE_FLIGHTRECORDER, > PARSE_EVENTS__TERM_TYPE_DRV_CFG, > __PARSE_EVENTS__TERM_TYPE_NR, > }; > diff --git a/tools/perf/util/parse-events.l b/tools/perf/util/parse-events.l > index 38a42bd..7710d6d 100644 > --- a/tools/perf/util/parse-events.l > +++ b/tools/perf/util/parse-events.l > @@ -251,8 +251,8 @@ stack-size { return term(yyscanner, > PARSE_EVENTS__TERM_TYPE_STACKSIZE); } > max-stack { return term(yyscanner, > PARSE_EVENTS__TERM_TYPE_MAX_STACK); } > 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); } > +flightrecorder { return term(yyscanner, > PARSE_EVENTS__TERM_TYPE_FLIGHTRECORDER); } > +no-flightrecorder { return term(yyscanner, > PARSE_EVENTS__TERM_TYPE_NOFLIGHTRECORDER); } > , { return ','; } > "/" { BEGIN(INITIAL); return '/'; } > {name_minus} { return str(yyscanner, PE_NAME); } > -- > 2.10.1
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