[PATCH v4 3/7] perf tools: Enable overwrite settings
From: Wang Nan
Date: Mon May 23 2016 - 22:34:21 EST
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/ ...
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@xxxxxxxxxx>
Signed-off-by: He Kuang <hekuang@xxxxxxxxxx>
Cc: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@xxxxxxxxxxx>
Cc: Namhyung Kim <namhyung@xxxxxxxxxx>
Cc: Zefan Li <lizefan@xxxxxxxxxx>
Cc: pi3orama@xxxxxxx
---
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