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

From: kan . liang
Date: Fri Mar 13 2015 - 10:05:12 EST

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)

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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