[tip:perf/core] perf tools: Enable overwrite settings

From: tip-bot for Wang Nan
Date: Sat Jul 16 2016 - 16:51:10 EST

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Commit-ID: 626a6b784e91bc61ca9fe0f9dd5bb60cb91ccb6b
Gitweb: http://git.kernel.org/tip/626a6b784e91bc61ca9fe0f9dd5bb60cb91ccb6b
Author: Wang Nan <wangnan0@xxxxxxxxxx>
AuthorDate: Thu, 14 Jul 2016 08:34:45 +0000
Committer: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
CommitDate: Fri, 15 Jul 2016 17:27:51 -0300

perf tools: Enable overwrite settings

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 the config term array size because
the longest string length has changed.

For overwritable events, it automatically selects attr.write_backward
since perf requires it to be backward for reading.

Test result:

# perf record --overwrite -e syscalls:*enter_nanosleep* usleep 1
[ perf record: Woken up 2 times to write data ]
[ perf record: Captured and wrote 0.011 MB perf.data (1 samples) ]
# perf evlist -v
syscalls:sys_enter_nanosleep: type: 2, size: 112, config: 0x134, { 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

Signed-off-by: Wang Nan <wangnan0@xxxxxxxxxx>
Tested-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
Acked-by: Jiri Olsa <jolsa@xxxxxxxxxx>
Cc: Masami Hiramatsu <mhiramat@xxxxxxxxxx>
Cc: Namhyung Kim <namhyung@xxxxxxxxxx>
Cc: Nilay Vaish <nilayvaish@xxxxxxxxx>
Cc: Zefan Li <lizefan@xxxxxxxxxx>
Cc: pi3orama@xxxxxxx
Link: http://lkml.kernel.org/r/1468485287-33422-14-git-send-email-wangnan0@xxxxxxxxxx
Signed-off-by: He Kuang <hekuang@xxxxxxxxxx>
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
---
tools/perf/Documentation/perf-record.txt | 14 ++++++++++++++
tools/perf/builtin-record.c | 1 +
tools/perf/perf.h | 1 +
tools/perf/tests/backward-ring-buffer.c | 10 +++++-----
tools/perf/util/evsel.c | 4 ++++
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 ++
9 files changed, 49 insertions(+), 7 deletions(-)

diff --git a/tools/perf/Documentation/perf-record.txt b/tools/perf/Documentation/perf-record.txt
index 5b46b1d..384c630 100644
--- a/tools/perf/Documentation/perf-record.txt
+++ b/tools/perf/Documentation/perf-record.txt
@@ -367,6 +367,20 @@ options.
'perf record --dry-run -e' can act as a BPF script compiler if llvm.dump-obj
in config file is set to true.

+--overwrite::
+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
+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/'.
+
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 b87070b..39c7486 100644
--- a/tools/perf/builtin-record.c
+++ b/tools/perf/builtin-record.c
@@ -1399,6 +1399,7 @@ 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/tests/backward-ring-buffer.c b/tools/perf/tests/backward-ring-buffer.c
index db9cd30..615780c 100644
--- a/tools/perf/tests/backward-ring-buffer.c
+++ b/tools/perf/tests/backward-ring-buffer.c
@@ -108,7 +108,11 @@ int test__backward_ring_buffer(int subtest __maybe_unused)
}

bzero(&parse_error, sizeof(parse_error));
- err = parse_events(evlist, "syscalls:sys_enter_prctl", &parse_error);
+ /*
+ * Set backward bit, ring buffer should be writing from end. Record
+ * it in aux evlist
+ */
+ err = parse_events(evlist, "syscalls:sys_enter_prctl/overwrite/", &parse_error);
if (err) {
pr_debug("Failed to parse tracepoint event, try use root\n");
ret = TEST_SKIP;
@@ -117,10 +121,6 @@ int test__backward_ring_buffer(int subtest __maybe_unused)

perf_evlist__config(evlist, &opts, NULL);

- /* Set backward bit, ring buffer should be writing from end */
- evlist__for_each_entry(evlist, evsel)
- evsel->attr.write_backward = 1;
-
err = perf_evlist__open(evlist);
if (err < 0) {
pr_debug("perf_evlist__open: %s\n",
diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c
index 9ac2f92..8c54df6 100644
--- a/tools/perf/util/evsel.c
+++ b/tools/perf/util/evsel.c
@@ -695,6 +695,9 @@ 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;
+ break;
default:
break;
}
@@ -776,6 +779,7 @@ 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;

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 e60cbfc..8a4a6c9 100644
--- a/tools/perf/util/evsel.h
+++ b/tools/perf/util/evsel.h
@@ -45,6 +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_MAX,
};

@@ -59,6 +60,7 @@ struct perf_evsel_config_term {
u64 stack_user;
int max_stack;
bool inherit;
+ bool overwrite;
} val;
};

diff --git a/tools/perf/util/parse-events.c b/tools/perf/util/parse-events.c
index 375af0e..6c913c3 100644
--- a/tools/perf/util/parse-events.c
+++ b/tools/perf/util/parse-events.c
@@ -902,6 +902,8 @@ 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",
};

static bool config_term_shrinked;
@@ -994,6 +996,12 @@ 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;
@@ -1046,6 +1054,8 @@ 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:
return config_term_common(attr, term, err);
default:
if (err) {
@@ -1118,6 +1128,12 @@ 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);
+ break;
+ case PARSE_EVENTS__TERM_TYPE_NOOVERWRITE:
+ ADD_CONFIG_TERM(OVERWRITE, overwrite, term->val.num ? 0 : 1);
+ break;
default:
break;
}
@@ -2412,9 +2428,9 @@ 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 b4aa7eb..d1edbf8 100644
--- a/tools/perf/util/parse-events.h
+++ b/tools/perf/util/parse-events.h
@@ -69,6 +69,8 @@ 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_NR,
};

diff --git a/tools/perf/util/parse-events.l b/tools/perf/util/parse-events.l
index 3c15b33..7a25194 100644
--- a/tools/perf/util/parse-events.l
+++ b/tools/perf/util/parse-events.l
@@ -202,6 +202,8 @@ 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); }
, { return ','; }
"/" { BEGIN(INITIAL); return '/'; }
{name_minus} { return str(yyscanner, PE_NAME); }

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