RE: [PATCH 1/1] perf, tool: partial callgrap and time support in perf record

From: Liang, Kan
Date: Mon Mar 16 2015 - 16:35:41 EST

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>
> Hi Kan,
>
> On Fri, Mar 13, 2015 at 02:18:07AM +0000, kan.liang@xxxxxxxxx wrote:
> > From: Kan Liang <kan.liang@xxxxxxxxx>
> >
> > When multiple events are sampled it may not be needed to collect
> > callgraphs for all of them. The sample sites are usually nearby, and
> > it's enough to collect the callgraphs on a reference event (such as
> > precise cycles or precise instructions). Similarly we also don't need
> > fine grained time stamps on all events, as it's enough to have time
> > stamps on the regular reference events. This patchkit adds the ability
> > to turn off callgraphs and time stamps per event. This in term can
> > reduce sampling overhead and the size of the perf.data (add some data)
>
> Have you taken a look into group sampling feature?
> (e.g. perf record -e '{ev1,ev2}:S')
>

I didn't find any issues when running group read.
The patch doesn't change the behavior of group read features.

Did you observe any issues after applying the patch?

Thanks,
Kan

> Thanks,
> Namhyung
>
>
> >
> > Here is an example.
> >
> > Collect callgrap and time for all events. The perf.data size is ~22M
> >
> > $ sudo ./perf record -e
> > cpu/cpu-cycles,period=100000/,cpu/instructions,period=20000/p
> > --call-graph fp ./tchain_edit
> > [ perf record: Woken up 92 times to write data ] [ perf record:
> > Captured and wrote 22.909 MB perf.data (249446 samples) ]
> >
> > Only collect callgrap and time on first event. The size is ~12M
> >
> > $ sudo ./perf record -e
> > cpu/cpu-cycles,callgraph=1,time=1,period=100000/,
> > cpu/instructions,callgraph=0,time=0,period=20000/p
> > ./tchain_edit
> > [ perf record: Woken up 50 times to write data ] [ perf record:
> > Captured and wrote 12.489 MB perf.data (203267 samples) ]
> >
> > perf reprot result for the second event.
> > Samples: 101K of event
> > 'cpu/instructions,callgraph=0,time=0,period=20000/p', Event count
> > (approx.): 2035000000
> > Children Self Command Shared Object Symbol
> > - 97.79% 0.00% tchain_edit libc-2.15.so [.]
> > __libc_start_main
> > __libc_start_main
> > - 97.79% 0.00% tchain_edit tchain_edit [.] main
> > main
> > __libc_start_main
> > - 97.79% 0.00% tchain_edit tchain_edit [.] f1
> > f1
> > main
> > __libc_start_main
> > - 97.79% 0.00% tchain_edit tchain_edit [.] f2
> > f2
> > f1
> > main
> > __libc_start_main
> > - 97.79% 97.42% tchain_edit tchain_edit [.] f3
> > f3
> > f2
> > f1
> > main
> > __libc_start_main
> >
> > Signed-off-by: Kan Liang <kan.liang@xxxxxxxxx>
> > ---
> > tools/perf/Documentation/perf-record.txt | 13 +++++++++
> > tools/perf/builtin-record.c | 7 +++--
> > tools/perf/perf.h | 2 ++
> > tools/perf/util/evsel.c | 50
> ++++++++++++++++++++++++++++++--
> > tools/perf/util/parse-events.c | 33 +++++++++++++++++++++
> > tools/perf/util/parse-events.h | 3 ++
> > tools/perf/util/parse-events.l | 3 ++
> > tools/perf/util/parse-options.c | 2 ++
> > tools/perf/util/parse-options.h | 4 +++
> > 9 files changed, 111 insertions(+), 6 deletions(-)
> >
> > diff --git a/tools/perf/Documentation/perf-record.txt
> > b/tools/perf/Documentation/perf-record.txt
> > index 355c4f5..8b3e76c0 100644
> > --- a/tools/perf/Documentation/perf-record.txt
> > +++ b/tools/perf/Documentation/perf-record.txt
> > @@ -45,6 +45,19 @@ OPTIONS
> > param1 and param2 are defined as formats for the PMU in:
> > /sys/bus/event_sources/devices/<pmu>/format/*
> >
> > + There are also some params which are not defined
> in .../<pmu>/format/*.
> > + These params can be used to set event defaults.
> > + Here is a list of the params.
> > + - 'period': Set event sampling period
> > + - 'callgraph': Disable/enable callgraph. Acceptable values are
> > + 1 for FP mode, 2 for dwarf mode, 3 for LBR mode,
> > + 0 for disabling callgraph.
> > + - 'stack_size': user stack size for dwarf mode
> > + - 'time': Disable/enable time stamping. Acceptable values are
> > + 1 for enabling time stamping. 0 for disabling time stamping.
> > + Note: If user explicitly sets options which conflict with the params,
> > + the value set by the params will be overridden.
> > +
> > - a hardware breakpoint event in the form of
> '\mem:addr[/len][:access]'
> > where addr is the address in memory you want to break in.
> > Access is the memory access type (read, write, execute) it
> > can diff --git a/tools/perf/builtin-record.c
> > b/tools/perf/builtin-record.c index 5a2ff51..bf536d1 100644
> > --- a/tools/perf/builtin-record.c
> > +++ b/tools/perf/builtin-record.c
> > @@ -795,10 +795,10 @@ struct option __record_options[] = {
> > perf_evlist__parse_mmap_pages),
> > OPT_BOOLEAN(0, "group", &record.opts.group,
> > "put the counters into a counter group"),
> > - OPT_CALLBACK_NOOPT('g', NULL, &record.opts,
> > + OPT_CALLBACK_NOOPT_SET('g', NULL, &record.opts,
> > +&record.opts.callgraph_set,
> > NULL, "enables call-graph recording" ,
> > &record_callchain_opt),
> > - OPT_CALLBACK(0, "call-graph", &record.opts,
> > + OPT_CALLBACK_SET(0, "call-graph", &record.opts,
> > +&record.opts.callgraph_set,
> > "mode[,dump_size]", record_callchain_help,
> > &record_parse_callchain_opt),
> > OPT_INCR('v', "verbose", &verbose,
> > @@ -808,7 +808,8 @@ struct option __record_options[] = {
> > "per thread counts"),
> > OPT_BOOLEAN('d', "data", &record.opts.sample_address,
> > "Sample addresses"),
> > - OPT_BOOLEAN('T', "timestamp", &record.opts.sample_time,
> "Sample timestamps"),
> > + OPT_BOOLEAN_SET('T', "timestamp", &record.opts.sample_time,
> > + &record.opts.sample_time_set, "Sample
> timestamps"),
> > OPT_BOOLEAN('P', "period", &record.opts.period, "Sample
> period"),
> > OPT_BOOLEAN('n', "no-samples", &record.opts.no_samples,
> > "don't sample"),
> > diff --git a/tools/perf/perf.h b/tools/perf/perf.h index
> > 1caa70a..72ebc91 100644
> > --- a/tools/perf/perf.h
> > +++ b/tools/perf/perf.h
> > @@ -51,9 +51,11 @@ struct record_opts {
> > bool sample_address;
> > bool sample_weight;
> > bool sample_time;
> > + bool sample_time_set;
> > bool period;
> > bool sample_intr_regs;
> > bool running_time;
> > + bool callgraph_set;
> > unsigned int freq;
> > unsigned int mmap_pages;
> > unsigned int user_freq;
> > diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c index
> > bb4eff2..88a695b 100644
> > --- a/tools/perf/util/evsel.c
> > +++ b/tools/perf/util/evsel.c
> > @@ -614,10 +614,53 @@ void perf_evsel__config(struct perf_evsel
> *evsel, struct record_opts *opts)
> > struct perf_event_attr *attr = &evsel->attr;
> > int track = evsel->tracking;
> > bool per_cpu = opts->target.default_per_cpu &&
> > !opts->target.per_thread;
> > + bool sample_time = opts->sample_time;
> > + bool callgraph = callchain_param.enabled;
> >
> > attr->sample_id_all = perf_missing_features.sample_id_all ? 0 : 1;
> > attr->inherit = !opts->no_inherit;
> >
> > + /*
> > + * If user doesn't explicitly set callgraph or time option,
> > + * let event attribute decide.
> > + */
> > + if (!opts->callgraph_set) {
> > + if (attr->sample_type & PERF_SAMPLE_CALLCHAIN) {
> > + callgraph = true;
> > + if (attr->sample_type &
> PERF_SAMPLE_STACK_USER) {
> > + callchain_param.record_mode =
> CALLCHAIN_DWARF;
> > + if (attr->sample_stack_user)
> > + callchain_param.dump_size = attr-
> >sample_stack_user;
> > + else
> > + callchain_param.dump_size = 8192;
> > + } else if (attr->sample_type &
> PERF_SAMPLE_BRANCH_STACK)
> > + callchain_param.record_mode =
> CALLCHAIN_LBR;
> > + else
> > + callchain_param.record_mode =
> CALLCHAIN_FP;
> > + } else
> > + callgraph = false;
> > + }
> > + /*
> > + * Clear the bit which parse event may be set,
> > + * Let perf_evsel__config_callgraph check and reset later.
> > + */
> > + attr->sample_type &= ~(PERF_SAMPLE_CALLCHAIN |
> > + PERF_SAMPLE_STACK_USER |
> > + PERF_SAMPLE_BRANCH_STACK);
> > +
> > +
> > + if (!opts->sample_time_set) {
> > + if (attr->sample_type & PERF_SAMPLE_TIME)
> > + sample_time = true;
> > + else
> > + sample_time = false;
> > + }
> > + if (attr->sample_type & PERF_SAMPLE_TIME) {
> > + attr->sample_type &= ~PERF_SAMPLE_TIME;
> > + /* remove the size which add in perf_evsel__init */
> > + evsel->sample_size -= sizeof(u64);
> > + }
> > +
> > perf_evsel__set_sample_bit(evsel, IP);
> > perf_evsel__set_sample_bit(evsel, TID);
> >
> > @@ -683,7 +726,7 @@ void perf_evsel__config(struct perf_evsel *evsel,
> struct record_opts *opts)
> > if (perf_evsel__is_function_event(evsel))
> > evsel->attr.exclude_callchain_user = 1;
> >
> > - if (callchain_param.enabled && !evsel->no_aux_samples)
> > + if (callgraph && !evsel->no_aux_samples)
> > perf_evsel__config_callgraph(evsel, opts);
> >
> > if (opts->sample_intr_regs) {
> > @@ -700,13 +743,14 @@ void perf_evsel__config(struct perf_evsel
> *evsel, struct record_opts *opts)
> > /*
> > * When the user explicitely disabled time don't force it here.
> > */
> > - if (opts->sample_time &&
> > + if (sample_time &&
> > (!perf_missing_features.sample_id_all &&
> > (!opts->no_inherit || target__has_cpu(&opts->target) ||
> per_cpu)))
> > perf_evsel__set_sample_bit(evsel, TIME);
> >
> > if (opts->raw_samples && !evsel->no_aux_samples) {
> > - perf_evsel__set_sample_bit(evsel, TIME);
> > + if (sample_time)
> > + perf_evsel__set_sample_bit(evsel, TIME);
> > perf_evsel__set_sample_bit(evsel, RAW);
> > perf_evsel__set_sample_bit(evsel, CPU);
> > }
> > diff --git a/tools/perf/util/parse-events.c
> > b/tools/perf/util/parse-events.c index fe07573..d0f30fb 100644
> > --- a/tools/perf/util/parse-events.c
> > +++ b/tools/perf/util/parse-events.c
> > @@ -17,6 +17,7 @@
> > #include "parse-events-flex.h"
> > #include "pmu.h"
> > #include "thread_map.h"
> > +#include "callchain.h"
> >
> > #define MAX_NAME_LEN 100
> >
> > @@ -570,6 +571,38 @@ do {
> \
> > * attr->branch_sample_type = term->val.num;
> > */
> > break;
> > + case PARSE_EVENTS__TERM_TYPE_CALLGRAPH:
> > + CHECK_TYPE_VAL(NUM);
> > + switch (term->val.num) {
> > + case CALLCHAIN_FP:
> > + attr->sample_type |= PERF_SAMPLE_CALLCHAIN;
> > + break;
> > + case CALLCHAIN_DWARF:
> > + attr->sample_type |= PERF_SAMPLE_CALLCHAIN |
> > + PERF_SAMPLE_STACK_USER;
> > + break;
> > + case CALLCHAIN_LBR:
> > + attr->sample_type |= PERF_SAMPLE_CALLCHAIN |
> > + PERF_SAMPLE_BRANCH_STACK;
> > + break;
> > + case CALLCHAIN_NONE:
> > + break;
> > + default:
> > + return -EINVAL;;
> > + }
> > + break;
> > + case PARSE_EVENTS__TERM_TYPE_STACKSIZE:
> > + CHECK_TYPE_VAL(NUM);
> > + attr->sample_stack_user = term->val.num;
> > + break;
> > + case PARSE_EVENTS__TERM_TYPE_TIME:
> > + CHECK_TYPE_VAL(NUM);
> > +
> > + if (term->val.num > 1)
> > + return -EINVAL;
> > + if (term->val.num == 1)
> > + attr->sample_type |= PERF_SAMPLE_TIME;
> > + break;
> > case PARSE_EVENTS__TERM_TYPE_NAME:
> > CHECK_TYPE_VAL(STR);
> > break;
> > diff --git a/tools/perf/util/parse-events.h
> > b/tools/perf/util/parse-events.h index 52a2dda..2c16367 100644
> > --- a/tools/perf/util/parse-events.h
> > +++ b/tools/perf/util/parse-events.h
> > @@ -60,6 +60,9 @@ enum {
> > PARSE_EVENTS__TERM_TYPE_NAME,
> > PARSE_EVENTS__TERM_TYPE_SAMPLE_PERIOD,
> > PARSE_EVENTS__TERM_TYPE_BRANCH_SAMPLE_TYPE,
> > + PARSE_EVENTS__TERM_TYPE_CALLGRAPH,
> > + PARSE_EVENTS__TERM_TYPE_STACKSIZE,
> > + PARSE_EVENTS__TERM_TYPE_TIME,
> > };
> >
> > struct parse_events_term {
> > diff --git a/tools/perf/util/parse-events.l
> > b/tools/perf/util/parse-events.l index 94eacb6..655306b 100644
> > --- a/tools/perf/util/parse-events.l
> > +++ b/tools/perf/util/parse-events.l
> > @@ -151,6 +151,9 @@ config2 { return
> term(yyscanner, PARSE_EVENTS__TERM_TYPE_CONFIG2); }
> > name { return term(yyscanner,
> PARSE_EVENTS__TERM_TYPE_NAME); }
> > period { return term(yyscanner,
> PARSE_EVENTS__TERM_TYPE_SAMPLE_PERIOD); }
> > branch_type { return term(yyscanner,
> PARSE_EVENTS__TERM_TYPE_BRANCH_SAMPLE_TYPE); }
> > +callgraph { return term(yyscanner,
> PARSE_EVENTS__TERM_TYPE_CALLGRAPH); }
> > +stack_size { return term(yyscanner,
> PARSE_EVENTS__TERM_TYPE_STACKSIZE); }
> > +time { return term(yyscanner,
> PARSE_EVENTS__TERM_TYPE_TIME); }
> > , { return ','; }
> > "/" { BEGIN(INITIAL); return '/'; }
> > {name_minus} { return str(yyscanner, PE_NAME); }
> > diff --git a/tools/perf/util/parse-options.c
> > b/tools/perf/util/parse-options.c index 1457d66..3786abb 100644
> > --- a/tools/perf/util/parse-options.c
> > +++ b/tools/perf/util/parse-options.c
> > @@ -123,6 +123,8 @@ static int get_value(struct parse_opt_ctx_t *p,
> > return 0;
> >
> > case OPTION_CALLBACK:
> > + if (opt->set)
> > + *(bool *)opt->set = true;
> > if (unset)
> > return (*opt->callback)(opt, NULL, 1) ? (-1) : 0;
> > if (opt->flags & PARSE_OPT_NOARG)
> > diff --git a/tools/perf/util/parse-options.h
> > b/tools/perf/util/parse-options.h index 97b153f..20d0d29 100644
> > --- a/tools/perf/util/parse-options.h
> > +++ b/tools/perf/util/parse-options.h
> > @@ -126,8 +126,12 @@ struct option {
> > { .type = OPTION_CALLBACK, .short_name = (s), .long_name = (l),
> > .value = (v), .argh = "time", .help = (h), .callback =
> parse_opt_approxidate_cb } #define OPT_CALLBACK(s, l, v, a, h, f) \
> > { .type = OPTION_CALLBACK, .short_name = (s), .long_name = (l),
> > .value = (v), (a), .help = (h), .callback = (f) }
> > +#define OPT_CALLBACK_SET(s, l, v, os, a, h, f) \
> > + { .type = OPTION_CALLBACK, .short_name = (s), .long_name = (l),
> > +.value = (v), (a), .help = (h), .callback = (f), .set =
> > +check_vtype(os, bool *) }
> > #define OPT_CALLBACK_NOOPT(s, l, v, a, h, f) \
> > { .type = OPTION_CALLBACK, .short_name = (s), .long_name = (l),
> > .value = (v), (a), .help = (h), .callback = (f), .flags =
> > PARSE_OPT_NOARG }
> > +#define OPT_CALLBACK_NOOPT_SET(s, l, v, os, a, h, f) \
> > + { .type = OPTION_CALLBACK, .short_name = (s), .long_name = (l),
> > +.value = (v), (a), .help = (h), .callback = (f), .flags =
> > +PARSE_OPT_NOARG, .set = check_vtype(os, bool *) }
> > #define OPT_CALLBACK_DEFAULT(s, l, v, a, h, f, d) \
> > { .type = OPTION_CALLBACK, .short_name = (s), .long_name = (l),
> > .value = (v), (a), .help = (h), .callback = (f), .defval =
> > (intptr_t)d, .flags = PARSE_OPT_LASTARG_DEFAULT } #define
> > OPT_CALLBACK_DEFAULT_NOOPT(s, l, v, a, h, f, d) \
> > --
> > 1.7.11.7
> >
> > --
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