In the current version, when using perf record, if something goes
wrong in tools/perf/builtin-record.c:375
session = perf_session__new(file, false, NULL);
The error message:
"Not enough memory for reading per file header"
is issued. This error message seems to be outdated and is not very
helpful. This patch proposes to replace this error message by
"Perf session creation failed"
I believe this issue has been brought to lkml:
https://lkml.org/lkml/2014/2/24/458
although this patch only tackles a (small) part of the issue.
Additionnaly, this patch improves error reporting in
tools/perf/util/data.c open_file_write.
Currently, if the call to open fails, the user is unaware of it.
This patch logs the error, before returning the error code to
the caller.
Reported-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Adrien BAK <adrien.bak@metascale.org>
Link: http://lkml.kernel.org/r/1397786443.3093.4.camel@beast
[ Reorganize the changelog into paragraphs ]
[ Added empty line after fd declaration in open_file_write ]
Signed-off-by: Jiri Olsa <jolsa@redhat.com>
pert-report doesn't resolve function names in VDSO:
$ perf report --stdio -g flat,0.0,15,callee --sort pid
...
8.76%
0x7fff6b1fe861
__gettimeofday
ACE_OS::gettimeofday()
...
In this case symbol values should be adjusted the same way as for executables,
relocatable objects and prelinked libraries.
After fix:
$ perf report --stdio -g flat,0.0,15,callee --sort pid
...
8.76%
__vdso_gettimeofday
__gettimeofday
ACE_OS::gettimeofday()
Signed-off-by: Vladimir Nikulichev <nvs@tbricks.com>
Tested-by: Namhyung Kim <namhyung@kernel.org>
Reviewed-by: Adrian Hunter <adrian.hunter@intel.com>
Link: http://lkml.kernel.org/r/969812.163009436-sendEmail@nvs
Signed-off-by: Jiri Olsa <jolsa@redhat.com>
Every event in the perf-kvm has a 'stats' structure, which contains
max/min/average/etc times of handling this event.
The problem is that the 'perf-kvm stat report' command always shows
that 'min time' is 0us for every event. Example:
# perf kvm stat report
Analyze events for all VCPUs:
VM-EXIT Samples Samples% Time% Min Time Max Time Avg time
[..]
0xB2 MSCH 12 0.07% 0.00% 0us 8us 7.31us ( +- 2.11% )
0xB2 CHSC 12 0.07% 0.00% 0us 18us 9.39us ( +- 9.49% )
0xB2 STPX 8 0.05% 0.00% 0us 2us 1.88us ( +- 7.18% )
0xB2 STSI 7 0.04% 0.00% 0us 44us 16.49us ( +- 38.20% )
[..]
This happens because the 'stats' structure is not initialized and
stats->min equals to 0. Lets initialize the structure for every
event after its allocation using init_stats() function. This initializes
stats->min to -1 and makes 'Min time' statistics counting work:
# perf kvm stat report
Analyze events for all VCPUs:
VM-EXIT Samples Samples% Time% Min Time Max Time Avg time
[..]
0xB2 MSCH 12 0.07% 0.00% 6us 8us 7.31us ( +- 2.11% )
0xB2 CHSC 12 0.07% 0.00% 7us 18us 9.39us ( +- 9.49% )
0xB2 STPX 8 0.05% 0.00% 1us 2us 1.88us ( +- 7.18% )
0xB2 STSI 7 0.04% 0.00% 1us 44us 16.49us ( +- 38.20% )
[..]
Signed-off-by: Alexander Yarygin <yarygin@linux.vnet.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Reviewed-by: David Ahern <dsahern@gmail.com>
Link: http://lkml.kernel.org/r/1397053319-2130-3-git-send-email-borntraeger@de.ibm.com
[ Fixing the perf examples changelog output ]
Signed-off-by: Jiri Olsa <jolsa@redhat.com>
perf stat did initialize the stats structure used to compute
stddev etc. incorrectly. It merely zeroes it. But one member
(min) needs to be set to a non zero value. This causes min
to be not computed at all. Call init_stats() correctly.
It doesn't matter for stat currently because it doesn't use
min, but it's still better to do it correctly.
The other users of statistics are already correct.
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Link: http://lkml.kernel.org/r/1395768699-16060-1-git-send-email-andi@firstfloor.org
Signed-off-by: Jiri Olsa <jolsa@redhat.com>
As Namhyung reported(https://lkml.org/lkml/2014/4/1/89),
current perf-probe -L option doesn't handle errors in line-range
searching correctly. It causes a SEGV if an error occured in the
line-range searching.
----
$ perf probe -x ./perf -v -L map__load
Open Debuginfo file: /home/namhyung/project/linux/tools/perf/perf
fname: util/map.c, lineno:153
New line range: 153 to 2147483647
path: (null)
Segmentation fault (core dumped)
----
This is because line_range_inline_cb() ignores errors
from find_line_range_by_line() which means that lr->path is
already freed on the error path in find_line_range_by_line().
As a result, get_real_path() accesses the lr->path and it
causes a NULL pointer exception.
This fixes line_range_inline_cb() to handle the error correctly,
and report it to the caller.
Anyway, this just fixes a possible SEGV bug, Namhyung's patch
is also required.
Reported-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
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/r/20140402054831.19080.27006.stgit@ltc230.yrl.intra.hitachi.co.jp
Signed-off-by: Jiri Olsa <jolsa@redhat.com>
I.e. do the same as when NO_LIBELF is explicitely passed in the 'make'
command line, fixing this:
Auto-detecting system features:
... dwarf: [ OFF ]
... glibc: [ on ]
... gtk2: [ OFF ]
... libaudit: [ OFF ]
... libbfd: [ OFF ]
... libelf: [ OFF ]
... libunwind: [ OFF ]
... libdw-dwarf-unwind: [ OFF ]
... DWARF post unwind library: libdw
<SNIP>
CC /tmp/build/perf/util/symbol-minimal.o
CC /tmp/build/perf/util/unwind-libdw.o
arch/x86/util/unwind-libdw.c:1:30: fatal error: elfutils/libdwfl.h: No such file or directory
compilation terminated.
CC /tmp/build/perf/tests/keep-tracking.o
util/unwind-libdw.c:2:28: fatal error: elfutils/libdw.h: No such file or directory
compilation terminated.
Cc: Adrian Hunter <adrian.hunter@intel.com>
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: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/n/tip-e39j1yxanltjx4t0msse63ax@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Jiri Olsa <jolsa@redhat.com>
Pull arch/tile updates from Chris Metcalf:
"These fix a few stray build issues seen in linux-next, and also add
the minimal required support for perf to tilegx"
* git://git.kernel.org/pub/scm/linux/kernel/git/cmetcalf/linux-tile:
arch/tile: remove unused variable 'devcap'
tile: Fix vDSO compilation issue with allyesconfig
perf tools: Allow building for tile
tile/perf: Support perf_events on tilegx and tilepro
tile: Enable NMIs on return from handle_nmi() without errors
tile: Add support for handling PMC hardware
tile: don't use __get_cpu_var() with structure-typed arguments
tile: avoid overflow in ns2cycles
Pull perf changes from Ingo Molnar:
"Main changes:
Kernel side changes:
- Add SNB/IVB/HSW client uncore memory controller support (Stephane
Eranian)
- Fix various x86/P4 PMU driver bugs (Don Zickus)
Tooling, user visible changes:
- Add several futex 'perf bench' microbenchmarks (Davidlohr Bueso)
- Speed up thread map generation (Don Zickus)
- Introduce 'perf kvm --list-cmds' command line option for use by
scripts (Ramkumar Ramachandra)
- Print the evsel name in the annotate stdio output, prep to fix
support outputting annotation for multiple events, not just for the
first one (Arnaldo Carvalho de Melo)
- Allow setting preferred callchain method in .perfconfig (Jiri Olsa)
- Show in what binaries/modules 'perf probe's are set (Masami
Hiramatsu)
- Support distro-style debuginfo for uprobe in 'perf probe' (Masami
Hiramatsu)
Tooling, internal changes and fixes:
- Use tid in mmap/mmap2 events to find maps (Don Zickus)
- Record the reason for filtering an address_location (Namhyung Kim)
- Apply all filters to an addr_location (Namhyung Kim)
- Merge al->filtered with hist_entry->filtered in report/hists
(Namhyung Kim)
- Fix memory leak when synthesizing thread records (Namhyung Kim)
- Use ui__has_annotation() in 'report' (Namhyung Kim)
- hists browser refactorings to reuse code accross UIs (Namhyung Kim)
- Add support for the new DWARF unwinder library in elfutils (Jiri
Olsa)
- Fix build race in the generation of bison files (Jiri Olsa)
- Further streamline the feature detection display, trimming it a bit
to show just the libraries detected, using VF=1 gets a more verbose
output, showing the less interesting feature checks as well (Jiri
Olsa).
- Check compatible symtab type before loading dso (Namhyung Kim)
- Check return value of filename__read_debuglink() (Stephane Eranian)
- Move some hashing and fs related code from tools/perf/util/ to
tools/lib/ so that it can be used by more tools/ living utilities
(Borislav Petkov)
- Prepare DWARF unwinding code for using an elfutils alternative
unwinding library (Jiri Olsa)
- Fix DWARF unwind max_stack processing (Jiri Olsa)
- Add dwarf unwind 'perf test' entry (Jiri Olsa)
- 'perf probe' improvements including memory leak fixes, sharing the
intlist class with other tools, uprobes/kprobes code sharing and
use of ref_reloc_sym (Masami Hiramatsu)
- Shorten sample symbol resolving by adding cpumode to struct
addr_location (Arnaldo Carvalho de Melo)
- Fix synthesizing mmaps for threads (Don Zickus)
- Fix invalid output on event group stdio report (Namhyung Kim)
- Fixup header alignment in 'perf sched latency' output (Ramkumar
Ramachandra)
- Fix off-by-one error in 'perf timechart record' argv handling
(Ramkumar Ramachandra)
Tooling, cleanups:
- Remove unused thread__find_map function (Jiri Olsa)
- Remove unused simple_strtoul() function (Ramkumar Ramachandra)
Tooling, documentation updates:
- Update function names in debug messages (Ramkumar Ramachandra)
- Update some code references in design.txt (Ramkumar Ramachandra)
- Clarify load-latency information in the 'perf mem' docs (Andi
Kleen)
- Clarify x86 register naming in 'perf probe' docs (Andi Kleen)"
* 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (96 commits)
perf tools: Remove unused simple_strtoul() function
perf tools: Update some code references in design.txt
perf evsel: Update function names in debug messages
perf tools: Remove thread__find_map function
perf annotate: Print the evsel name in the stdio output
perf report: Use ui__has_annotation()
perf tools: Fix memory leak when synthesizing thread records
perf tools: Use tid in mmap/mmap2 events to find maps
perf report: Merge al->filtered with hist_entry->filtered
perf symbols: Apply all filters to an addr_location
perf symbols: Record the reason for filtering an address_location
perf sched: Fixup header alignment in 'latency' output
perf timechart: Fix off-by-one error in 'record' argv handling
perf machine: Factor machine__find_thread to take tid argument
perf tools: Speed up thread map generation
perf kvm: introduce --list-cmds for use by scripts
perf ui hists: Pass evsel to hpp->header/width functions explicitly
perf symbols: Introduce thread__find_cpumode_addr_location
perf session: Change header.misc dump from decimal to hex
perf ui/tui: Reuse generic __hpp__fmt() code
...
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>
Before:
---------------------------------------------------------------------------------------------------------------
Task | Runtime ms | Switches | Average delay ms | Maximum delay ms | Maximum delay at |
---------------------------------------------------------------------------------------------------------------
... | | | | |
git:24540 | 336.622 ms | 10 | avg: 0.032 ms | max: 0.062 ms | max at: 115610.111046 s
git:24541 | 0.457 ms | 1 | avg: 0.000 ms | max: 0.000 ms | max at: 0.000000 s
-----------------------------------------------------------------------------------------
TOTAL: | 396.542 ms | 353 |
---------------------------------------------------
After:
-----------------------------------------------------------------------------------------------------------------
Task | Runtime ms | Switches | Average delay ms | Maximum delay ms | Maximum delay at |
-----------------------------------------------------------------------------------------------------------------
... | | | | |
git:24540 | 336.622 ms | 10 | avg: 0.032 ms | max: 0.062 ms | max at: 115610.111046 s
git:24541 | 0.457 ms | 1 | avg: 0.000 ms | max: 0.000 ms | max at: 0.000000 s
-----------------------------------------------------------------------------------------------------------------
TOTAL: | 396.542 ms | 353 |
---------------------------------------------------
Signed-off-by: Ramkumar Ramachandra <artagnon@gmail.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Link: http://lkml.kernel.org/r/1395065901-25740-1-git-send-email-artagnon@gmail.com
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>
The for_each_bench() macro must check that the "benchmarks" field of a
collection is not NULL before dereferencing it because the "all"
collection in particular has a NULL "benchmarks" field (signifying that
it has no benchmarks to iterate over).
This fixes this NULL pointer dereference when running "perf bench all":
[root@ssdandy ~]# perf bench all
<SNIP>
# Running mem/memset benchmark...
# Copying 1MB Bytes ...
2.453675 GB/Sec
12.056327 GB/Sec (with prefault)
Segmentation fault (core dumped)
[root@ssdandy ~]#
Signed-off-by: Patrick Palka <patrick@parcs.ath.cx>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1394664051-6037-1-git-send-email-patrick@parcs.ath.cx
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>
Block a bunch of threads on a futex and requeue them on another, N at a
time.
This program is particularly useful to measure the latency of nthread
requeues without waking up any tasks -- thus mimicking a regular
futex_wait.
An example run:
$ perf bench futex requeue -r 100 -t 64
Run summary [PID 151011]: Requeuing 64 threads (from 0x7d15c4 to 0x7d15c8), 1 at a time.
[Run 1]: Requeued 64 of 64 threads in 0.0400 ms
[Run 2]: Requeued 64 of 64 threads in 0.0390 ms
[Run 3]: Requeued 64 of 64 threads in 0.0400 ms
...
[Run 100]: Requeued 64 of 64 threads in 0.0390 ms
Requeued 64 of 64 threads in 0.0399 ms (+-0.37%)
Signed-off-by: Davidlohr Bueso <davidlohr@hp.com>
Acked-by: Darren Hart <dvhart@linux.intel.com>
Cc: Aswin Chandramouleeswaran <aswin@hp.com>
Cc: Darren Hart <dvhart@linux.intel.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jason Low <jason.low2@hp.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Scott J Norton <scott.norton@hp.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Waiman Long <Waiman.Long@hp.com>
Link: http://lkml.kernel.org/r/1387081917-9102-4-git-send-email-davidlohr@hp.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Block a bunch of threads on a futex and wake them up, N at a time.
This program is particularly useful to measure the latency of nthread
wakeups in non-error situations: all waiters are queued and all wake
calls wakeup one or more tasks.
An example run:
$ perf bench futex wake -t 512 -r 100
Run summary [PID 27823]: blocking on 512 threads (at futex 0x7e10d4), waking up 1 at a time.
[Run 1]: Wokeup 512 of 512 threads in 6.0080 ms
[Run 2]: Wokeup 512 of 512 threads in 5.2280 ms
[Run 3]: Wokeup 512 of 512 threads in 4.8300 ms
...
[Run 100]: Wokeup 512 of 512 threads in 5.0100 ms
Wokeup 512 of 512 threads in 5.0109 ms (+-2.25%)
Signed-off-by: Davidlohr Bueso <davidlohr@hp.com>
Acked-by: Darren Hart <dvhart@linux.intel.com>
Cc: Aswin Chandramouleeswaran <aswin@hp.com>
Cc: Darren Hart <dvhart@linux.intel.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jason Low <jason.low2@hp.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Scott J Norton <scott.norton@hp.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Waiman Long <Waiman.Long@hp.com>
Link: http://lkml.kernel.org/r/1387081917-9102-3-git-send-email-davidlohr@hp.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Introduce futexes to perf-bench and add a program that stresses and
measures the kernel's implementation of the hash table.
This is a multi-threaded program that simply measures the amount of
failed futex wait calls - we only want to deal with the hashing
overhead, so a negative return of futex_wait_setup() is enough to do the
trick.
An example run:
$ perf bench futex hash -t 32
Run summary [PID 10989]: 32 threads, each operating on 1024 [private] futexes for 10 secs.
[thread 0] futexes: 0x19d9b10 ... 0x19dab0c [ 418713 ops/sec ]
[thread 1] futexes: 0x19daca0 ... 0x19dbc9c [ 469913 ops/sec ]
[thread 2] futexes: 0x19dbe30 ... 0x19dce2c [ 479744 ops/sec ]
...
[thread 31] futexes: 0x19fbb80 ... 0x19fcb7c [ 464179 ops/sec ]
Averaged 454310 operations/sec (+- 0.84%), total secs = 10
Signed-off-by: Davidlohr Bueso <davidlohr@hp.com>
Acked-by: Darren Hart <dvhart@linux.intel.com>
Cc: Aswin Chandramouleeswaran <aswin@hp.com>
Cc: Darren Hart <dvhart@linux.intel.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jason Low <jason.low2@hp.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Scott J Norton <scott.norton@hp.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Waiman Long <Waiman.Long@hp.com>
Link: http://lkml.kernel.org/r/1387081917-9102-2-git-send-email-davidlohr@hp.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
If we call just:
perf bench numa mem
it will present the same output as:
perf bench numa mem -h
i.e. ask for instructions about what to run.
While that is kinda ok, using 'run all tests' as the default, i.e.
making 'no parms' be equivalent to:
perf bench numa mem -a
Will allow:
perf bench numa all
to actually do what is asked: i.e. run all the 'bench' tests, instead of
responding to that by asking what to do.
That, in turn, allows:
perf bench all
to actually complete, for the same reasons.
And after that, the tests that come after that, and that at some point
hit a NULL deref, will run, allowing me to reproduce a recently reported
problem.
That when you have the needed numa libraries, which wasn't the case for
the reporter, making me a bit confused after trying to reproduce his
report.
So make no parms mean -a.
Cc: 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: Mike Galbraith <efault@gmx.de>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Patrick Palka <patrick@parcs.ath.cx>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/n/tip-x7h0ghx4pef4n0brywg21krk@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
