Adding the thread_map event to pass/store thread maps as data in
the pipe/perf.data.
Storing the thread ID along with the standard comm[16] thread name string.
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Tested-by: Kan Liang <kan.liang@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1445784728-21732-4-git-send-email-jolsa@kernel.org
[ Renamed thread_map_data_event to thread_map_event_entry ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Note that since the thread was already inserted to the session
list, it will be released when the session is released.
Also, in perf_session__register_idle_thread() failure path,
the thread should be put before returning.
Refcnt debugger shows that the perf_session__register_idle_thread
gets the returned thread, but the caller (__cmd_top) does not
put the returned idle thread.
----
==== [0] ====
Unreclaimed thread@0x24e6240
Refcount +1 => 0 at
./perf(thread__new+0xe5) [0x4c8a75]
./perf(machine__findnew_thread+0x9a) [0x4bbdba]
./perf(perf_session__register_idle_thread+0x28) [0x4c63c8]
./perf(cmd_top+0xd7d) [0x43cf6d]
./perf() [0x47ba35]
./perf(main+0x617) [0x4225b7]
/lib64/libc.so.6(__libc_start_main+0xf5) [0x7f06027c5af5]
./perf() [0x42272d]
Refcount +1 => 1 at
./perf(thread__get+0x2c) [0x4c8bcc]
./perf(machine__findnew_thread+0xee) [0x4bbe0e]
./perf(perf_session__register_idle_thread+0x28) [0x4c63c8]
./perf(cmd_top+0xd7d) [0x43cf6d]
./perf() [0x47ba35]
./perf(main+0x617) [0x4225b7]
/lib64/libc.so.6(__libc_start_main+0xf5) [0x7f06027c5af5]
./perf() [0x42272d]
Refcount +1 => 2 at
./perf(thread__get+0x2c) [0x4c8bcc]
./perf(machine__findnew_thread+0x112) [0x4bbe32]
./perf(perf_session__register_idle_thread+0x28) [0x4c63c8]
./perf(cmd_top+0xd7d) [0x43cf6d]
./perf() [0x47ba35]
./perf(main+0x617) [0x4225b7]
/lib64/libc.so.6(__libc_start_main+0xf5) [0x7f06027c5af5]
./perf() [0x42272d]
----
Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/20151209021122.10245.69707.stgit@localhost.localdomain
[ Drop the refcount in perf_session__register_idle_thread() ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Before:
[acme@zoo linux]$ perf evlist
WARNING: The perf.data file's data size field is 0 which is unexpected.
Was the 'perf record' command properly terminated?
non matching sample_type[acme@zoo linux]$
After:
[acme@zoo linux]$ perf evlist
WARNING: The perf.data file's data size field is 0 which is unexpected.
Was the 'perf record' command properly terminated?
non matching sample_type
[acme@zoo linux]$
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/n/tip-wscok3a2s7yrj8156oc2r6qe@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
The perf top didn't add the idle/swapper thread to the machine's thread
list and its comm was displayed as ':0'. Fix it.
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
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/1443577526-3240-3-git-send-email-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
By default 'perf record' will postprocess the perf.data file to
determine build-ids. When that happens, the number of lost perf events
is displayed.
Make that also happen for AUX events.
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Link: http://lkml.kernel.org/r/1443186956-18718-7-git-send-email-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
If a session contains no events, we can get stuck in an infinite loop in
__perf_session__process_events, with a non-zero file_size and data_offset, but
a zero data_size.
In this case, we can mmap the entirety of the file (consisting of the file and
attribute headers), and fetch_mmaped_event will correctly refuse to read any
(unmapped and non-existent) event headers. This causes
__perf_session__process_events to unmap the file and retry with the exact same
parameters, getting stuck in an infinite loop.
This has been observed to result in an exit-time hang when counting
rare/unschedulable events with perf record, and can be triggered artificially
with the script below:
----
#!/bin/sh
printf "REPRO: launching perf\n";
./perf record -e software/config=9/ sleep 1 &
PERF_PID=$!;
sleep 0.002;
kill -2 $PERF_PID;
printf "REPRO: waiting for perf (%d) to exit...\n" "$PERF_PID";
wait $PERF_PID;
printf "REPRO: perf exited\n";
----
To avoid this, have __perf_session__process_events bail out early when
the file has no data (i.e. it has no events).
Commiter note:
I only managed to reproduce this when setting
/proc/sys/kernel/kptr_restrict to '1' and changing the code to
purposefully not process any samples and no synthesized samples, i.e.
kptr_restrict prevents 'record' from synthesizing the kernel mmaps for
vmlinux + modules and since it is a workload started from perf, we don't
synthesize mmap/comm records for existing threads.
Adrian Hunter managed to reproduce it in his environment tho.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Tested-by: Arnaldo Carvalho de Melo <acme@kernel.org>
Tested-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1442423929-12253-1-git-send-email-mark.rutland@arm.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
The 'struct machine' represents the machine where the samples were/are
being collected, and we also have a 'struct perf_env' with extra details
about such machine, that we were collecting at 'perf.data' creation time
but we also needed when no perf.data file is being used, such as in
'perf top'.
So, get those structs closer together, as they provide a bigger picture
of the sample's environment.
In 'perf session', when the file argument is NULL, we can assume that
the tool is sampling the running machine, so point machine->env to
the global put in place in previous patches, while set it to the
perf_header.env one when reading from a file.
This paves the way for machine->env to be used in
perf_event__preprocess_sample to populate addr_location.socket.
Tested-by: Wang Nan <wangnan0@huawei.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Kan Liang <kan.liang@intel.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/n/tip-2ajotl0khscutm68exictoy9@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Since it can be used separately from 'perf_session' and 'perf_header',
move it to separate include file and object, next csets will try to move
a perf_env__init() routine.
Tested-by: Wang Nan <wangnan0@huawei.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Kan Liang <kan.liang@intel.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/n/tip-ff2rw99tsn670y1b6gxbwdsi@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Need to check evsel before passing it to dump_sample().
Signed-off-by: Kan Liang <kan.liang@intel.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/r/1441283463-51050-5-git-send-email-kan.liang@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
This patch stores the cpu socket_id and core_id in a perf.data header,
and reads them into the perf_env struct when processing perf.data files.
The changes modifies the CPU_TOPOLOGY section, making sure it is
backward/forward compatible.
The patch checks the section size before reading the core and socket ids.
It never reads data crossing the section boundary. An old perf binary
without this patch can also correctly read the perf.data from a new perf
with this patch.
Because the new info is added at the end of the cpu_topology section, an
old perf tool ignores the extra data.
Examples:
1. New perf with this patch read perf.data from an old perf without the
patch:
$ perf_new report -i perf_old.data --header-only -I
......
# sibling threads : 33
# sibling threads : 34
# sibling threads : 35
# Core ID and Socket ID information is not available
# node0 meminfo : total = 32823872 kB, free = 29315548 kB
# node0 cpu list : 0-17,36-53
......
2. Old perf without the patch reads perf.data from a new perf with the
patch:
$ perf_old report -i perf_new.data --header-only -I
......
# sibling threads : 33
# sibling threads : 34
# sibling threads : 35
# node0 meminfo : total = 32823872 kB, free = 29190932 kB
# node0 cpu list : 0-17,36-53
......
3. New perf read new perf.data:
$ perf_new report -i perf_new.data --header-only -I
......
# sibling threads : 33
# sibling threads : 34
# sibling threads : 35
# CPU 0: Core ID 0, Socket ID 0
# CPU 1: Core ID 1, Socket ID 0
......
# CPU 61: Core ID 10, Socket ID 1
# CPU 62: Core ID 11, Socket ID 1
# CPU 63: Core ID 16, Socket ID 1
# node0 meminfo : total = 32823872 kB, free = 29190932 kB
# node0 cpu list : 0-17,36-53
Signed-off-by: Kan Liang <kan.liang@intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Link: http://lkml.kernel.org/r/1441115893-22006-2-git-send-email-kan.liang@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
As it is not necessarily tied to a perf.data file and needs using in
places where a perf_session is not required.
Suggested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Kan Liang <kan.liang@intel.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/r/1440755289-30939-4-git-send-email-kan.liang@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
cycles is a new branch_info field available on some CPUs that indicates
the time deltas between branches in the LBR.
Add a sort key and output code for the cycles to allow to display the
basic block cycles individually in perf report.
We also pass in the cycles for weight when LBRs are processed, which
allows to get global and local weight, to get an estimate of the total
cost.
And also print the cycles information for perf report -D. I also added
printing for the previously missing LBR flags (mispredict etc.)
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: http://lkml.kernel.org/r/1437233094-12844-2-git-send-email-andi@firstfloor.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
The semantic associated in tools/perf/ with foo__delete(instance) is to
release all resources referenced by 'instance' members and then release
the memory for 'instance' itself.
The perf_session_env__delete() function isn't doing this, it just does
the first part, but the space used by 'instance' itself isn't freed, as
it is embedded in a larger structure, that will be freed at other stage.
For these cases we se foo__exit(), i.e. the usage is:
void foo__delete(foo)
{
if (foo) {
foo__exit(foo);
free(foo);
}
}
But when we have something like:
struct bar {
struct foo foo;
. . .
}
Then we can't really call foo__delete(&bar.foo), we must have this
instead:
void bar__exit(bar)
{
foo__exit(&bar.foo);
/* free other bar-> resources */
}
void bar__delete(bar)
{
if (bar) {
bar__exit(bar);
free(bar);
}
}
So just rename perf_session_env__delete() to perf_session_env__exit().
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Kan Liang <kan.liang@intel.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/n/tip-djbgpcfo5udqptx3q0flwtmk@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Support processing of PERF_RECORD_SWITCH events and
PERF_RECORD_SWITCH_CPU_WIDE events. There is a single
tools callback for them both so that the tool must
check the event type before using the extra members
in PERF_RECORD_SWITCH_CPU_WIDE.
There is still no way to select the events, though.
That is added in a subsequest patch.
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Jiri Olsa <jolsa@redhat.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Cc: Pawel Moll <pawel.moll@arm.com>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/r/1437471846-26995-3-git-send-email-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
We will reuse argv style data in following change to display counters
header showing monitored command line.
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1437481927-29538-12-git-send-email-jolsa@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Adding refference counting for cpu_map object, so it could be easily
shared among other objects.
Using cpu_map__put instead cpu_map__delete and making cpu_map__delete
static.
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/r/1435012588-9007-4-git-send-email-jolsa@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
When dumping events with 'perf report -D' the event print always starts
with a newline (see dump_event()).
Do the same with the "Aggregated stats" print so that it is not jammed
up against the last event print.
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Link: http://lkml.kernel.org/r/1435045969-15999-2-git-send-email-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
With 'perf report -D' the PERF_RECORD_FINISHED_ROUND event was printed
without a newline, resulting in:
0x91a18 [0x8]: PERF_RECORD_FINISHED_ROUNDAggregated stats
Other events print their details, but PERF_RECORD_FINISHED_ROUND doesn't
have any so just add a print for a newline.
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Link: http://lkml.kernel.org/r/1435045969-15999-1-git-send-email-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
The time out to limit the individual proc map processing was hard code
to 500ms. This patch introduce a new option --proc-map-timeout to make
the time limit configurable.
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/1434549071-25611-2-git-send-email-kan.liang@intel.com
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>
The thread-stack represents a thread's current stack. When a thread
exits there can still be many functions on the stack e.g. exit() can be
called many levels deep, so all the callers will never return. To get
that information output, the thread-stack must be flushed.
Previously it was assumed the thread-stack would be flushed when the
struct thread was deleted. With thread ref-counting it is no longer
clear when that will be, if ever. So instead explicitly flush all the
thread-stacks at the end of a session.
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Link: http://lkml.kernel.org/r/1432906425-9911-3-git-send-email-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Following error occurs when trying to use 'perf report' on x86_64 to
cross analysis a perf.data generated by an old perf on a big-endian
machine:
# perf report
*** Error in `/home/w00229757/perf': free(): invalid next size (fast): 0x00000000032c99f0 ***
======= Backtrace: =========
/lib64/libc.so.6(+0x6eeef)[0x7ff6ff7e2eef]
/lib64/libc.so.6(+0x78cae)[0x7ff6ff7eccae]
/lib64/libc.so.6(+0x79987)[0x7ff6ff7ed987]
/path/to/perf[0x4ac734]
/path/to/perf[0x4ac829]
/path/to/perf(perf_header__process_sections+0x129)[0x4ad2c9]
/path/to/perf(perf_session__read_header+0x2e1)[0x4ad9e1]
/path/to/perf(perf_session__new+0x168)[0x4bd458]
/path/to/perf(cmd_report+0xfa0)[0x43eb70]
/path/to/perf[0x47adc3]
/path/to/perf(main+0x5f6)[0x42fd06]
/lib64/libc.so.6(__libc_start_main+0xf5)[0x7ff6ff795bd5]
/path/to/perf[0x42fe35]
======= Memory map: ========
[SNIP]
The bug is in perf_event__attr_swap(). It swaps all fields in 'struct
perf_event_attr' without checking whether the swapped field exist or
not. In addition, in read_event_desc() allocs memory for attr according
to size read from perf.data.
Therefore, if the perf.data is collected by an old perf (without
aux_watermark, for example), when perf_event__attr_swap() swaping
attr->aux_watermark it destroy malloc's metadata.
This patch introduces boundary checking in perf_event__attr_swap(). It
adds macros bswap_field_64 and bswap_field_32 into
perf_event__attr_swap() to make it only swap exist fields.
Signed-off-by: Wang Nan <wangnan0@huawei.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Zefan Li <lizefan@huawei.com>
Cc: pi3orama@163.com
Link: http://lkml.kernel.org/r/1434534999-85347-1-git-send-email-wangnan0@huawei.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Failed in 32bit arch build like this:
CC /opt/h00206996/output/perf/arm32/builtin-record.o
util/session.c: In function ‘perf_session__warn_about_errors’:
util/session.c:1304:9: error: format ‘%lu’ expects argument of type ‘long unsigned int’,
but argument 2 has type ‘long long unsigned int’ [-Werror=format=]
builtin-report.c: In function ‘perf_evlist__tty_browse_hists’:
builtin-report.c:323:2: error: format ‘%lu’ expects argument of type ‘long unsigned int’,
but argument 3 has type ‘u64’ [-Werror=format=]
Replace %lu format strings in warning message with PRIu64 for u64
'total_lost_samples' to fix this problem.
Signed-off-by: He Kuang <hekuang@huawei.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Kan Liang <kan.liang@intel.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/r/1434026664-71642-1-git-send-email-hekuang@huawei.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>
perf_session__peek_event() generally leverages there being a single mmap
of the perf.data file, however on 32-bit platforms when there is more
that 32MiB of data, then there are multiple mmaps, so
perf_session__peek_event() reads from the file.
In that case a couple of bugs were exposed (note how the seg. fault
appears with >32M of data):
$ perf record --per-thread -e intel_bts// ../rtit-tests/loopy 1000000
[ perf record: Woken up 13 times to write data ]
[ perf record: Captured and wrote 24.568 MB perf.data ]
$ perf script > /dev/null
$ perf record --per-thread -e intel_bts// ../rtit-tests/loopy 10000000
[ perf record: Woken up 136 times to write data ]
[ perf record: Captured and wrote 270.794 MB perf.data ]
$ perf script > /dev/null
Segmentation fault (core dumped)
The wrong address was being passed to the readn() function and the
buffer size was not being checked.
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@gmail.com>
Link: http://lkml.kernel.org/r/1432040746-1755-5-git-send-email-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Add support for the PERF_RECORD_ITRACE_START event type. This event can
be used to determine the pid and tid that are running when Instruction
Tracing starts. Generally that information would come from a
sched_switch event but, at the start, no sched_switch events may yet
have been recorded.
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/1430404667-10593-8-git-send-email-adrian.hunter@intel.com
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 an index of AUX area tracing events within a perf.data file.
perf record uses a special user event PERF_RECORD_FINISHED_ROUND to
enable sorting of events in chunks instead of having to sort all events
altogether.
AUX area tracing events contain data that can span back to the very
beginning of the recording period. i.e. they do not obey the rules of
PERF_RECORD_FINISHED_ROUND.
By adding an index, AUX area tracing events can be found in advance and
the PERF_RECORD_FINISHED_ROUND approach works as usual.
The index is recorded with the auxtrace feature in the perf.data file.
A session reads the index but does not process it. An AUX area decoder
can queue all the AUX area data in advance using
auxtrace_queues__process_index() or otherwise process the index in some
custom manner.
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/1430404667-10593-3-git-send-email-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Add new AUX area member (aux_watermark) of struct perf_event_attr to
debug prints and byte swapping.
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
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: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/r/1428594864-29309-27-git-send-email-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Add functions to synthesize, count and print AUX area tracing error
events.
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
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: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/r/1428594864-29309-11-git-send-email-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Hook into session processing so that AUX area decoding can synthesize
events transparently to the tools.
The advantages of transparent decoding are that tools can be used
directly with perf.data files containing AUX area tracing data, which is
easier for the user and more efficient than having a separate decoding
tool.
This will work as follows:
1. Tools will feed auxtrace events to the decoder using
perf_tool->auxtrace() (support for that still to come).
2. The decoder can process side-band events as needed due
to the auxtrace->process_event() hook.
3. The decoder can deliver synthesized events into the
event stream using perf_session__deliver_synth_event().
Note the expectation is that decoding will work on data that is
time-ordered with respect to the per-cpu or per-thread contexts that
were recorded.
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
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: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/r/1428594864-29309-9-git-send-email-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Errors encountered when decoding an AUX area trace need to be reported
to the user. However the "user" might be a script or another tool, so
provide a new user event to capture those errors.
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/1428594864-29309-8-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>
This patch add checks in places where map__kmap is used to get kmaps
from struct kmap.
Error messages are added at map__kmap to warn invalid accessing of kmap
(for the case of !map->dso->kernel, kmap(map) does not exists at all).
Also, introduces map__kmaps() to warn uninitialized kmaps.
Reviewed-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Wang Nan <wangnan0@huawei.com>
Cc: pi3orama@163.com
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Zefan Li <lizefan@huawei.com>
Link: http://lkml.kernel.org/r/1428394966-131044-2-git-send-email-wangnan0@huawei.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
As these can be obtained from the ordered_events pointer, via
container_of, reducing the cross section of ordered_samples.
These were added to ordered_samples in:
commit b7b61cbebd
Author: Arnaldo Carvalho de Melo <acme@redhat.com>
Date: Tue Mar 3 11:58:45 2015 -0300
perf ordered_events: Shorten function signatures
By keeping pointers to machines, evlist and tool in ordered_events.
But that was more a transitional patch while moving stuff out from
perf_session.c to ordered_events.c and possibly not even needed by then,
as we could use the container_of() method and instead of having the
nr_unordered_samples stats in events_stats, we can have it in
ordered_samples.
Based-on-a-patch-by: Jiri Olsa <jolsa@kernel.org>
Acked-by: Jiri Olsa <jolsa@kernel.org>
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: Namhyung Kim <namhyung@kernel.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/n/tip-4lk0t9js82g0tfc0x1onpkjt@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Even when it is not used to actually reorder events, some of its fields
are used, like session->ordered_events->tool, to shorten function
signatures where tool, for instance, was being passed, as the tool is
needed for the ordered_events code, we need it there and might as well
use it for other perf_session needs.
This fixes a problem where 'perf script' had some condition that made
session->ordered_events not to be initialized even with its
script->tool ordered_events related flags asking for it to be, which
looks like another bug and needs to be investigated further.
Always initializing session->ordered_events at least leaves the current
assumptions in place, so do it now.
Reported-by: David Ahern <dsahern@gmail.com>
Reviewed-by: David Ahern <dsahern@gmail.com>
Tested-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-b1xxk0rwkz2a0gip1uufmjqg@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
From perf_session, will be used in 'trace'.
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-mfihndzaumx44h6y37ng2irb@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
It is all about flushing the ordered queue or piping it thru, no need
for a perf_session pointer.
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-g47fx3ys0t9271cp0dcabjc7@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
So that we can simplify the deliver method to pass just:
(ordered_events, ordered_event, sample);
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-j0s4bpxs5qza5tnkvjwom9rw@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
By keeping pointers to machines, evlist and tool in ordered_events.
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-0c6huyaf59mqtm2ek9pmposl@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
For use by tools that are not perf.data based, as maybe 'perf trace' in
live mode.
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-nedqe7cmii5w82etfi36urfz@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
We need to do that to stop accumulating entries in the dead_threads
linked list, i.e. we were keeping references to threads in struct hists
that continue to exist even after a thread exited and was removed from
the machine threads rbtree.
We still keep the dead_threads list, but just for debugging, allowing us
to iterate at any given point over the threads that still are referenced
by things like struct hist_entry.
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-3ejvfyed0r7ue61dkurzjux4@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
All it wants is session->evlist.
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: Mike Galbraith <efault@gmx.de>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/n/tip-6w9663gka3jb1j1rfxxd5jcq@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
For tools that don't deal with perf.data files, thus do not need to
use perf_session.
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: Mike Galbraith <efault@gmx.de>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/n/tip-kglq67gvauq9tak02a4se00r@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Start to untangle session from delivering samples, as there are
tools that want to use ordered_events and don't use perf_session at all.
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: Mike Galbraith <efault@gmx.de>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/n/tip-rn4pk3pjxd78sgzrkn19tktp@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
LBR call stack only has user-space callchains. It is output in the
PERF_SAMPLE_BRANCH_STACK data format. For kernel callchains, it's
still in the form of PERF_SAMPLE_CALLCHAIN.
The perf tool has to handle both data sources to construct a
complete callstack.
For the "perf report -D" option, both lbr and fp information will be
displayed.
A new call chain recording option "lbr" is introduced into the perf
tool for LBR call stack. The user can use --call-graph lbr to get
the call stack information from hardware.
Here are some examples.
When profiling bc(1) on Fedora 19:
echo 'scale=2000; 4*a(1)' > cmd; perf record --call-graph lbr bc -l < cmd
If enabling LBR, perf report output looks like:
50.36% bc bc [.] bc_divide
|
--- bc_divide
execute
run_code
yyparse
main
__libc_start_main
_start
33.66% bc bc [.] _one_mult
|
--- _one_mult
bc_divide
execute
run_code
yyparse
main
__libc_start_main
_start
7.62% bc bc [.] _bc_do_add
|
--- _bc_do_add
|
|--99.89%-- 0x2000186a8
--0.11%-- [...]
6.83% bc bc [.] _bc_do_sub
|
--- _bc_do_sub
|
|--99.94%-- bc_add
| execute
| run_code
| yyparse
| main
| __libc_start_main
| _start
--0.06%-- [...]
0.46% bc libc-2.17.so [.] __memset_sse2
|
--- __memset_sse2
|
|--54.13%-- bc_new_num
| |
| |--51.00%-- bc_divide
| | execute
| | run_code
| | yyparse
| | main
| | __libc_start_main
| | _start
| |
| |--30.46%-- _bc_do_sub
| | bc_add
| | execute
| | run_code
| | yyparse
| | main
| | __libc_start_main
| | _start
| |
| --18.55%-- _bc_do_add
| bc_add
| execute
| run_code
| yyparse
| main
| __libc_start_main
| _start
|
--45.87%-- bc_divide
execute
run_code
yyparse
main
__libc_start_main
_start
If using FP, perf report output looks like:
echo 'scale=2000; 4*a(1)' > cmd; perf record --call-graph fp bc -l < cmd
50.49% bc bc [.] bc_divide
|
--- bc_divide
33.57% bc bc [.] _one_mult
|
--- _one_mult
7.61% bc bc [.] _bc_do_add
|
--- _bc_do_add
0x2000186a8
6.88% bc bc [.] _bc_do_sub
|
--- _bc_do_sub
0.42% bc libc-2.17.so [.] __memcpy_ssse3_back
|
--- __memcpy_ssse3_back
If using LBR, perf report -D output looks like:
3458145275743 0x2fd750 [0xd8]: PERF_RECORD_SAMPLE(IP, 0x2): 9748/9748: 0x408ea8 period: 609644 addr: 0
... LBR call chain: nr:8
..... 0: fffffffffffffe00
..... 1: 0000000000408e50
..... 2: 000000000040a458
..... 3: 000000000040562e
..... 4: 0000000000408590
..... 5: 00000000004022c0
..... 6: 00000000004015dd
..... 7: 0000003d1cc21b43
... FP chain: nr:2
..... 0: fffffffffffffe00
..... 1: 0000000000408ea8
... thread: bc:9748
...... dso: /usr/bin/bc
The LBR call stack has the following known limitations:
- Zero length calls are not filtered out by the hardware
- Exception handing such as setjmp/longjmp will have calls/returns not
match
- Pushing different return address onto the stack will have
calls/returns not match
- If callstack is deeper than the LBR, only the last entries are
captured
Tested-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Kan Liang <kan.liang@intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Borislav Petkov <bp@suse.de>
Cc: David Ahern <dsahern@gmail.com>
Cc: Don Zickus <dzickus@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Simon Que <sque@chromium.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/r/1420482185-29830-3-git-send-email-kan.liang@intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Jiri Olsa