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When perf creates a new child to profile, the events are enabled on
exec(). And in this case, it doesn't synthesize any event for the
child since they'll be generated during exec(). But there's an window
between the enabling and the event generation.
It used to be overcome since samples are only in kernel (so we always
have the map) and the comm is overridden by a later COMM event.
However it won't work if events are processed and displayed before the
COMM event overrides like in 'perf script'. This leads to those early
samples (like native_write_msr_safe) not having a comm but pid (like
':15328').
So it needs to synthesize COMM event for the child explicitly before
enabling so that it can have a correct comm. But at this time, the
comm will be "perf" since it's not exec-ed yet.
Committer note:
Before this patch:
# perf record usleep 1
[ perf record: Woken up 1 times to write data ]
[ perf record: Captured and wrote 0.017 MB perf.data (7 samples) ]
# perf script --show-task-events
:4429 4429 27909.079372: 1 cycles: ffffffff8105f45a native_write_msr_safe (/lib/modules/4.
:4429 4429 27909.079375: 1 cycles: ffffffff8105f45a native_write_msr_safe (/lib/modules/4.
:4429 4429 27909.079376: 10 cycles: ffffffff8105f45a native_write_msr_safe (/lib/modules/4.
:4429 4429 27909.079377: 223 cycles: ffffffff8105f45a native_write_msr_safe (/lib/modules/4.
:4429 4429 27909.079378: 6571 cycles: ffffffff8105f45a native_write_msr_safe (/lib/modules/4.
usleep 4429 27909.079380: PERF_RECORD_COMM exec: usleep:4429/4429
usleep 4429 27909.079381: 185403 cycles: ffffffff810a72d3 flush_signal_handlers (/lib/modules/4.
usleep 4429 27909.079444: 2241110 cycles: 7fc575355be3 _dl_start (/usr/lib64/ld-2.20.so)
usleep 4429 27909.079875: PERF_RECORD_EXIT(4429:4429):(4429:4429)
After:
# perf record usleep 1
[ perf record: Woken up 1 times to write data ]
[ perf record: Captured and wrote 0.017 MB perf.data (7 samples) ]
# perf script --show-task
perf 0 0.000000: PERF_RECORD_COMM: perf:8446/8446
perf 8446 30154.038944: 1 cycles: ffffffff8105f45a native_write_msr_safe (/lib/modules/4.
perf 8446 30154.038948: 1 cycles: ffffffff8105f45a native_write_msr_safe (/lib/modules/4.
perf 8446 30154.038949: 9 cycles: ffffffff8105f45a native_write_msr_safe (/lib/modules/4.
perf 8446 30154.038950: 230 cycles: ffffffff8105f45a native_write_msr_safe (/lib/modules/4.
perf 8446 30154.038951: 6772 cycles: ffffffff8105f45a native_write_msr_safe (/lib/modules/4.
usleep 8446 30154.038952: PERF_RECORD_COMM exec: usleep:8446/8446
usleep 8446 30154.038954: 196923 cycles: ffffffff81766440 _raw_spin_lock (/lib/modules/4.3.0-rc1
usleep 8446 30154.039021: 2292130 cycles: 7f609a173dc4 memcpy (/usr/lib64/ld-2.20.so)
usleep 8446 30154.039349: PERF_RECORD_EXIT(8446:8446):(8446:8446)
#
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1442881495-2928-1-git-send-email-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
System wide sampling like 'perf top' or 'perf record -a' read all
threads /proc/xxx/maps before sampling. If there are any threads which
generating a keeping growing huge maps, perf will do infinite loop
during synthesizing. Nothing will be sampled.
This patch fixes this issue by adding per-thread timeout to force stop
this kind of endless proc map processing.
PERF_RECORD_MISC_PROC_MAP_PARSE_TIME_OUT is introduced to indicate that
the mmap record are truncated by time out. User will get warning
notification when truncated mmap records are detected.
Reported-by: Ying Huang <ying.huang@intel.com>
Signed-off-by: Kan Liang <kan.liang@intel.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Ying Huang <ying.huang@intel.com>
Link: http://lkml.kernel.org/r/1434549071-25611-1-git-send-email-kan.liang@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
This patch modifies the perf tool to handle the new RECORD type,
PERF_RECORD_LOST_SAMPLES.
The number of lost-sample events is stored in
.nr_events[PERF_RECORD_LOST_SAMPLES]. The exact number of samples
which the kernel dropped is stored in total_lost_samples.
When the percentage of dropped samples is greater than 5%, a warning
is printed.
Here are some examples:
Eg 1, Recording different frequently-occurring events is safe with the
patch. Only a very low drop rate is associated with such actions.
$ perf record -e '{cycles:p,instructions:p}' -c 20003 --no-time ~/tchain ~/tchain
$ perf report -D | tail
SAMPLE events: 120243
MMAP2 events: 5
LOST_SAMPLES events: 24
FINISHED_ROUND events: 15
cycles:p stats:
TOTAL events: 59348
SAMPLE events: 59348
instructions:p stats:
TOTAL events: 60895
SAMPLE events: 60895
$ perf report --stdio --group
# To display the perf.data header info, please use --header/--header-only options.
#
#
# Total Lost Samples: 24
#
# Samples: 120K of event 'anon group { cycles:p, instructions:p }'
# Event count (approx.): 24048600000
#
# Overhead Command Shared Object Symbol
# ................ ........... ................
..................................
#
99.74% 99.86% tchain_edit tchain_edit [.] f3
0.09% 0.02% tchain_edit tchain_edit [.] f2
0.04% 0.00% tchain_edit [kernel.vmlinux] [k] ixgbe_read_reg
Eg 2, Recording the same thing multiple times can lead to high drop
rate, but it is not a useful configuration.
$ perf record -e '{cycles:p,cycles:p}' -c 20003 --no-time ~/tchain
Warning: Processed 600592 samples and lost 99.73% samples!
[perf record: Woken up 148 times to write data]
[perf record: Captured and wrote 36.922 MB perf.data (1206322 samples)]
[perf record: Woken up 1 times to write data]
[perf record: Captured and wrote 0.121 MB perf.data (1629 samples)]
Signed-off-by: Kan Liang <kan.liang@intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: acme@infradead.org
Cc: eranian@google.com
Link: http://lkml.kernel.org/r/1431285195-14269-9-git-send-email-kan.liang@intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
In addition to using refcounts for the struct thread lifetime
management, we need to protect access to machine->threads from
concurrent access.
That happens in 'perf top', where a thread processes events, inserting
and deleting entries from that rb_tree while another thread decays
hist_entries, that end up dropping references and ultimately deleting
threads from the rb_tree and releasing its resources when no further
hist_entry (or other data structures, like in 'perf sched') references
it.
So the rule is the same for refcounts + protected trees in the kernel,
get the tree lock, find object, bump the refcount, drop the tree lock,
return, use object, drop the refcount if no more use of it is needed,
keep it if storing it in some other data structure, drop when releasing
that data structure.
I.e. pair "t = machine__find(new)_thread()" with a "thread__put(t)", and
"perf_event__preprocess_sample(&al)" with "addr_location__put(&al)".
The addr_location__put() one is because as we return references to
several data structures, we may end up adding more reference counting
for the other data structures and then we'll drop it at
addr_location__put() time.
Acked-by: David Ahern <dsahern@gmail.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: Don Zickus <dzickus@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/n/tip-bs9rt4n0jw3hi9f3zxyy3xln@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Add support for the PERF_RECORD_AUX event type.
PERF_RECORD_AUX is a new kernel event that records when new data lands
in the AUX buffer. Currently it is assumed that AUX data follows the
same ring buffer conventions used by the perf events buffer, and
consequently the AUX event is not processed during recording.
It is processed during session processing so that the information in the
'flags' member is made available.
The format of PERF_RECORD_AUX is outlined in the linux/perf_events.h
header file. The 'flags' are also enumerated.
Intel PT and Intel BTS use the flag named PERF_AUX_FLAG_TRUNCATED to
determine if data has been lost because the buffer became full as perf
was not able to empty it fast enough.
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Namhyung Kim <namhyung@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/r/1430404667-10593-7-git-send-email-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Add two user events for AUX area tracing.
PERF_RECORD_AUXTRACE_INFO contains metadata, consisting primarily the
type of the AUX area tracing data plus some amount of
architecture-specific information. There should be only one
PERF_RECORD_AUXTRACE_INFO event.
PERF_RECORD_AUXTRACE identifies AUX area tracing data copied from the
mmapped AUX area tracing region. The actual data is not part of the
event but immediately follows it.
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Namhyung Kim <namhyung@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/r/1428594864-29309-4-git-send-email-adrian.hunter@intel.com
[ s/MIN/min/g and use cast to fix up wrt -Werror=sign-compare till we adopt min_t() ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
In this commit:
commit 363b785f38
Author: Don Zickus <dzickus@redhat.com>
Date: Fri Mar 14 10:43:44 2014 -0400
perf tools: Speed up thread map generation
We ended up emitting PERF_RECORD_FORK events after their corresponding
PERF_RECORD_COMM, so the code below will remove the "existing thread"
and then recreates it, unnecessarily:
[root@ssdandy ~]# perf probe -x ~/bin/perf -L machine__process_fork_event
<machine__process_fork_event@/home/acme/git/linux/tools/perf/util/machine.c:0>
0 int machine__process_fork_event(struct machine *machine, union perf_event *event,
struct perf_sample *sample)
2 {
3 struct thread *thread = machine__find_thread(machine,
event->fork.pid,
event->fork.tid);
6 struct thread *parent = machine__findnew_thread(machine,
event->fork.ppid,
event->fork.ptid);
/* if a thread currently exists for the thread id remove it */
if (thread != NULL)
12 machine__remove_thread(machine, thread);
14 thread = machine__findnew_thread(machine, event->fork.pid,
event->fork.tid);
16 if (dump_trace)
17 perf_event__fprintf_task(event, stdout);
19 if (thread == NULL || parent == NULL ||
20 thread__fork(thread, parent, sample->time) < 0) {
21 dump_printf("problem processing PERF_RECORD_FORK, skipping event.\n");
22 return -1;
}
25 return 0;
26 }
[root@ssdandy ~]# perf probe -x ~/bin/perf fork_after_comm=machine__process_fork_event:12
Added new event:
probe_perf:fork_after_comm (on machine__process_fork_event:12 in /home/acme/bin/perf)
You can now use it in all perf tools, such as:
perf record -e probe_perf:fork_after_comm -aR sleep 1
[root@ssdandy ~]#
[root@ssdandy ~]# perf record -g -e probe_perf:* trace -o /tmp/bla
^C[ perf record: Woken up 1 times to write data ]
[ perf record: Captured and wrote 0.021 MB perf.data (30 samples) ]
Terminated
[root@ssdandy ~]#
[root@ssdandy ~]# perf report --no-children --show-total-period --stdio
# To display the perf.data header info, please use --header/--header-only options.
#
# Samples: 30 of event 'probe_perf:fork_after_comm'
# Event count (approx.): 30
#
# Overhead Period Command Shared Object Symbol
# ........ ............ ....... ............. ...............................
#
100.00% 30 trace trace [.] machine__process_fork_event
|
---machine__process_fork_event
__event__synthesize_thread.part.2
perf_event__synthesize_threads
cmd_trace
main
__libc_start_main
[root@ssdandy ~]#
And Looking at 'perf report -D' output we see it:
0 0 0x8698 [0x30]: PERF_RECORD_COMM: auditd:703/707
0 0 0x86c8 [0x38]: PERF_RECORD_FORK(703:707):(703:703)
Fix it by more closely mimicking how the kernel generates those records
when a new fork happens, i.e. first a PERF_RECORD_FORK, then a
PERF_RECORD_COMM.
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: David Ahern <dsahern@gmail.com>
Cc: Don Zickus <dzickus@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/n/tip-h0emvymi2t3mw8dlqd6d6z73@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Add an index of the event identifiers, in preparation for Intel PT.
The event id (also called the sample id) is a unique number
allocated by the kernel to the event created by perf_event_open(). Events
can include the event id by having a sample type including PERF_SAMPLE_ID or
PERF_SAMPLE_IDENTIFIER.
Currently the main use of the event id is to match an event back to the
evsel to which it belongs i.e. perf_evlist__id2evsel()
The purpose of this patch is to make it possible to match an event back to
the mmap from which it was read. The reason that is useful is because the
mmap represents a time-ordered context (either for a cpu or for a thread).
Intel PT decodes trace information on that basis. In full-trace mode, that
information can be recorded when the Intel PT trace is read, but in
sample-mode the Intel PT trace data is embedded in a sample and it is in
that case that the "id index" is needed.
So the mmaps are numbered (idx) and the cpu and tid recorded against the id
by perf_evlist__set_sid_idx() which is called by perf_evlist__mmap_per_evsel().
That information is recorded on the perf.data file in the new "id index".
idx, cpu and tid are added to struct perf_sample_id (which is the node of
evlist's hash table to match ids to evsels). The information can be
retrieved using perf_evlist__id2sid(). Note however this all depends on
having a sample type including PERF_SAMPLE_ID or PERF_SAMPLE_IDENTIFIER,
otherwise ids are not recorded.
The "id index" is a synthesized event record which will be created when
Intel PT sampling is used by calling perf_event__synthesize_id_index().
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@gmail.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/r/1414417770-18602-2-git-send-email-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Instead of bailing out as soon as we find a filter that applies, go on
checking all of them so that we can zoom in/out filters.
We also need to make sure we only update al->filtered after
thread__find_addr_map(), because there is where al->filtered gets
initialized to zero.
This will increase the cost of processing when all we don't need this
toggling, but will provide flexibility for the TUI and GTK+ interfaces,
that will incur in creating the hist_entries just once.
Signed-off-by: Namhyung Kim <namhyung.kim@lge.com>
Acked-by: Jiri Olsa <jolsa@redhat.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung.kim@lge.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/n/tip-fhv9lhzdjxgp9w3w3668lsfw@git.kernel.org
[ yanked this out of a previous patch ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
When trying to capture perf data on a system running spejbb2013, perf
hung for about 15 minutes. This is because it took that long to gather
about 10,000 thread maps and process them.
I don't think a user wants to wait that long.
Instead, recognize that thread maps are roughly equivalent to pid maps
and just quickly copy those instead.
To do this, I synthesize 'fork' events, this eventually calls
thread__fork() and copies the maps over.
The overhead goes from 15 minutes down to about a few seconds.
--
V2: based on Jiri's comments, moved malloc up a level
and made sure the memory was freed
Signed-off-by: Don Zickus <dzickus@redhat.com>
Acked-by: Jiri Olsa <jolsa@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Joe Mario <jmario@redhat.com>
Link: http://lkml.kernel.org/r/1394808224-113774-1-git-send-email-dzickus@redhat.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Currently if a process creates a bunch of threads using pthread_create
and then perf is run in system_wide mode, the mmaps for those threads
are not captured with a synthesized mmap event.
The reason is those threads are not visible when walking the /proc/
directory looking for /proc/<pid>/maps files. Instead they are
discovered using the /proc/<pid>/tasks file (which the synthesized comm
event uses).
This causes problems when a program is trying to map a data address to a
tid. Because the tid has no maps, the event is dropped. Changing the
program to look up using the pid instead of the tid, finds the correct
maps but creates ugly hacks in the program to carry the correct tid
around.
Fix this by moving the walking of the /proc/<pid>/tasks up a level (out
of the comm function) based on Arnaldo's suggestion.
Tweaked things a bit to special case the 'full' bit and 'guest' check.
Signed-off-by: Don Zickus <dzickus@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/r/1393429527-167840-2-git-send-email-dzickus@redhat.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
When introducing the PERF_RECORD_MMAP2 in:
5c5e854bc7 perf tools: Add attr->mmap2 support
A check for the number of entries parsed by sscanf was introduced that
assumed all of the 8 fields needed to be correctly parsed so that
particular /proc/pid/maps line would be considered synthesizable.
That broke anon records synthesizing, as it doesn't have the 'execname'
field.
Fix it by keeping the sscanf return check, changing it to not require
that the 'execname' variable be parsed, so that the preexisting logic
can kick in and set it to '//anon'.
This should get things like JIT profiling working again.
Signed-off-by: Don Zickus <dzickus@redhat.com>
Cc: Bill Gray <bgray@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Joe Mario <jmario@redhat.com>
Cc: Richard Fowles <rfowles@redhat.com>
Cc: Stephane Eranian <eranian@google.com>
Cc: stable@vger.kernel.org
Link: http://lkml.kernel.org/n/tip-bo4akalno7579shpz29u867j@git.kernel.org
[ commit log message is mine, dzickus reported the problem with a patch ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
