[tip:perf/core] perf python: Support the PERF_RECORD_SWITCH event

From: tip-bot for Arnaldo Carvalho de Melo
Date: Thu Oct 08 2015 - 05:47:59 EST

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Commit-ID: ae938802443732e77d01f8d5b52b900b9327ff30
Gitweb: http://git.kernel.org/tip/ae938802443732e77d01f8d5b52b900b9327ff30
Author: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
AuthorDate: Tue, 6 Oct 2015 17:46:46 -0300
Committer: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
CommitDate: Wed, 7 Oct 2015 19:41:50 -0300

perf python: Support the PERF_RECORD_SWITCH event

To test it check tools/perf/python/twatch.py, after following the
instructions there to enable context_switch, output looks like:

[root@zoo linux]# tools/perf/python/twatch.py
cpu: 1, pid: 31463, tid: 31463 { type: context_switch, next_prev_pid: 31463, next_prev_tid: 31463, switch_out: 0 }
cpu: 2, pid: 31463, tid: 31496 { type: context_switch, next_prev_pid: 31463, next_prev_tid: 31496, switch_out: 0 }
cpu: 2, pid: 31463, tid: 31496 { type: context_switch, next_prev_pid: 31463, next_prev_tid: 31496, switch_out: 1 }
cpu: 3, pid: 31463, tid: 31527 { type: context_switch, next_prev_pid: 31463, next_prev_tid: 31527, switch_out: 0 }
cpu: 1, pid: 31463, tid: 31463 { type: context_switch, next_prev_pid: 31463, next_prev_tid: 31463, switch_out: 1 }
cpu: 3, pid: 31463, tid: 31527 { type: context_switch, next_prev_pid: 31463, next_prev_tid: 31527, switch_out: 1 }
cpu: 1, pid: 31463, tid: 31463 { type: context_switch, next_prev_pid: 31463, next_prev_tid: 31463, switch_out: 0 }
^CTraceback (most recent call last):
File "tools/perf/python/twatch.py", line 67, in <module>
main(context_switch = 1, thread = 31463)
File "tools/perf/python/twatch.py", line 40, in main
evlist.poll(timeout = -1)
KeyboardInterrupt
[root@zoo linux]#

Cc: Adrian Hunter <adrian.hunter@xxxxxxxxx>
Cc: Borislav Petkov <bp@xxxxxxx>
Cc: David Ahern <dsahern@xxxxxxxxx>
Cc: Frederic Weisbecker <fweisbec@xxxxxxxxx>
Cc: Guy Streeter <streeter@xxxxxxxxxx>
Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
Cc: Namhyung Kim <namhyung@xxxxxxxxxx>
Cc: Stephane Eranian <eranian@xxxxxxxxxx>
Cc: Wang Nan <wangnan0@xxxxxxxxxx>
Link: http://lkml.kernel.org/n/tip-1ukistmpamc5z717k80ctcp2@xxxxxxxxxxxxxx
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
---
tools/perf/python/twatch.py | 23 +++++++++++++++---
tools/perf/util/python.c | 59 ++++++++++++++++++++++++++++++++++++++++++---
2 files changed, 75 insertions(+), 7 deletions(-)

diff --git a/tools/perf/python/twatch.py b/tools/perf/python/twatch.py
index b9d5083..c235c22 100755
--- a/tools/perf/python/twatch.py
+++ b/tools/perf/python/twatch.py
@@ -15,14 +15,14 @@

import perf

-def main():
+def main(context_switch = 0, thread = -1):
cpus = perf.cpu_map()
- threads = perf.thread_map()
+ threads = perf.thread_map(thread)
evsel = perf.evsel(type = perf.TYPE_SOFTWARE,
config = perf.COUNT_SW_DUMMY,
task = 1, comm = 1, mmap = 0, freq = 0,
wakeup_events = 1, watermark = 1,
- sample_id_all = 1,
+ sample_id_all = 1, context_switch = context_switch,
sample_type = perf.SAMPLE_PERIOD | perf.SAMPLE_TID | perf.SAMPLE_CPU)

"""What we want are just the PERF_RECORD_ lifetime events for threads,
@@ -48,4 +48,21 @@ def main():
print event

if __name__ == '__main__':
+ """
+ To test the PERF_RECORD_SWITCH record, pick a pid and replace
+ in the following line.
+
+ Example output:
+
+cpu: 3, pid: 31463, tid: 31593 { type: context_switch, next_prev_pid: 31463, next_prev_tid: 31593, switch_out: 1 }
+cpu: 1, pid: 31463, tid: 31489 { type: context_switch, next_prev_pid: 31463, next_prev_tid: 31489, switch_out: 1 }
+cpu: 2, pid: 31463, tid: 31496 { type: context_switch, next_prev_pid: 31463, next_prev_tid: 31496, switch_out: 1 }
+cpu: 3, pid: 31463, tid: 31491 { type: context_switch, next_prev_pid: 31463, next_prev_tid: 31491, switch_out: 0 }
+
+ It is possible as well to use event.misc & perf.PERF_RECORD_MISC_SWITCH_OUT
+ to figure out if this is a context switch in or out of the monitored threads.
+
+ If bored, please add command line option parsing support for these options :-)
+ """
+ # main(context_switch = 1, thread = 31463)
main()
diff --git a/tools/perf/util/python.c b/tools/perf/util/python.c
index 6324fe6..98f127a 100644
--- a/tools/perf/util/python.c
+++ b/tools/perf/util/python.c
@@ -67,6 +67,7 @@ static char pyrf_mmap_event__doc[] = PyDoc_STR("perf mmap event object.");
static PyMemberDef pyrf_mmap_event__members[] = {
sample_members
member_def(perf_event_header, type, T_UINT, "event type"),
+ member_def(perf_event_header, misc, T_UINT, "event misc"),
member_def(mmap_event, pid, T_UINT, "event pid"),
member_def(mmap_event, tid, T_UINT, "event tid"),
member_def(mmap_event, start, T_ULONGLONG, "start of the map"),
@@ -297,6 +298,43 @@ static PyTypeObject pyrf_sample_event__type = {
.tp_repr = (reprfunc)pyrf_sample_event__repr,
};

+static char pyrf_context_switch_event__doc[] = PyDoc_STR("perf context_switch event object.");
+
+static PyMemberDef pyrf_context_switch_event__members[] = {
+ sample_members
+ member_def(perf_event_header, type, T_UINT, "event type"),
+ member_def(context_switch_event, next_prev_pid, T_UINT, "next/prev pid"),
+ member_def(context_switch_event, next_prev_tid, T_UINT, "next/prev tid"),
+ { .name = NULL, },
+};
+
+static PyObject *pyrf_context_switch_event__repr(struct pyrf_event *pevent)
+{
+ PyObject *ret;
+ char *s;
+
+ if (asprintf(&s, "{ type: context_switch, next_prev_pid: %u, next_prev_tid: %u, switch_out: %u }",
+ pevent->event.context_switch.next_prev_pid,
+ pevent->event.context_switch.next_prev_tid,
+ !!(pevent->event.header.misc & PERF_RECORD_MISC_SWITCH_OUT)) < 0) {
+ ret = PyErr_NoMemory();
+ } else {
+ ret = PyString_FromString(s);
+ free(s);
+ }
+ return ret;
+}
+
+static PyTypeObject pyrf_context_switch_event__type = {
+ PyVarObject_HEAD_INIT(NULL, 0)
+ .tp_name = "perf.context_switch_event",
+ .tp_basicsize = sizeof(struct pyrf_event),
+ .tp_flags = Py_TPFLAGS_DEFAULT|Py_TPFLAGS_BASETYPE,
+ .tp_doc = pyrf_context_switch_event__doc,
+ .tp_members = pyrf_context_switch_event__members,
+ .tp_repr = (reprfunc)pyrf_context_switch_event__repr,
+};
+
static int pyrf_event__setup_types(void)
{
int err;
@@ -306,6 +344,7 @@ static int pyrf_event__setup_types(void)
pyrf_lost_event__type.tp_new =
pyrf_read_event__type.tp_new =
pyrf_sample_event__type.tp_new =
+ pyrf_context_switch_event__type.tp_new =
pyrf_throttle_event__type.tp_new = PyType_GenericNew;
err = PyType_Ready(&pyrf_mmap_event__type);
if (err < 0)
@@ -328,6 +367,9 @@ static int pyrf_event__setup_types(void)
err = PyType_Ready(&pyrf_sample_event__type);
if (err < 0)
goto out;
+ err = PyType_Ready(&pyrf_context_switch_event__type);
+ if (err < 0)
+ goto out;
out:
return err;
}
@@ -342,6 +384,8 @@ static PyTypeObject *pyrf_event__type[] = {
[PERF_RECORD_FORK] = &pyrf_task_event__type,
[PERF_RECORD_READ] = &pyrf_read_event__type,
[PERF_RECORD_SAMPLE] = &pyrf_sample_event__type,
+ [PERF_RECORD_SWITCH] = &pyrf_context_switch_event__type,
+ [PERF_RECORD_SWITCH_CPU_WIDE] = &pyrf_context_switch_event__type,
};

static PyObject *pyrf_event__new(union perf_event *event)
@@ -349,8 +393,10 @@ static PyObject *pyrf_event__new(union perf_event *event)
struct pyrf_event *pevent;
PyTypeObject *ptype;

- if (event->header.type < PERF_RECORD_MMAP ||
- event->header.type > PERF_RECORD_SAMPLE)
+ if ((event->header.type < PERF_RECORD_MMAP ||
+ event->header.type > PERF_RECORD_SAMPLE) &&
+ !(event->header.type == PERF_RECORD_SWITCH ||
+ event->header.type == PERF_RECORD_SWITCH_CPU_WIDE))
return NULL;

ptype = pyrf_event__type[event->header.type];
@@ -528,6 +574,7 @@ static int pyrf_evsel__init(struct pyrf_evsel *pevsel,
"exclude_hv",
"exclude_idle",
"mmap",
+ "context_switch",
"comm",
"freq",
"inherit_stat",
@@ -553,6 +600,7 @@ static int pyrf_evsel__init(struct pyrf_evsel *pevsel,
exclude_hv = 0,
exclude_idle = 0,
mmap = 0,
+ context_switch = 0,
comm = 0,
freq = 1,
inherit_stat = 0,
@@ -565,13 +613,13 @@ static int pyrf_evsel__init(struct pyrf_evsel *pevsel,
int idx = 0;

if (!PyArg_ParseTupleAndKeywords(args, kwargs,
- "|iKiKKiiiiiiiiiiiiiiiiiiiiiKK", kwlist,
+ "|iKiKKiiiiiiiiiiiiiiiiiiiiiiKK", kwlist,
&attr.type, &attr.config, &attr.sample_freq,
&sample_period, &attr.sample_type,
&attr.read_format, &disabled, &inherit,
&pinned, &exclusive, &exclude_user,
&exclude_kernel, &exclude_hv, &exclude_idle,
- &mmap, &comm, &freq, &inherit_stat,
+ &mmap, &context_switch, &comm, &freq, &inherit_stat,
&enable_on_exec, &task, &watermark,
&precise_ip, &mmap_data, &sample_id_all,
&attr.wakeup_events, &attr.bp_type,
@@ -595,6 +643,7 @@ static int pyrf_evsel__init(struct pyrf_evsel *pevsel,
attr.exclude_hv = exclude_hv;
attr.exclude_idle = exclude_idle;
attr.mmap = mmap;
+ attr.context_switch = context_switch;
attr.comm = comm;
attr.freq = freq;
attr.inherit_stat = inherit_stat;
@@ -1019,6 +1068,8 @@ static struct {
PERF_CONST(RECORD_LOST_SAMPLES),
PERF_CONST(RECORD_SWITCH),
PERF_CONST(RECORD_SWITCH_CPU_WIDE),
+
+ PERF_CONST(RECORD_MISC_SWITCH_OUT),
{ .name = NULL, },
};

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Next message: Russell King - ARM Linux: "Re: [PATCH v8 3/6] pci:host: Add Altera PCIe host controller driver"
Previous message: tip-bot for Andrzej Hajda: "[tip:perf/core] perf tools: Fix handling read result using a signed variable"
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