perf bench sched pipe: Add -G/--cgroups option

The -G/--cgroups option is to put sender and receiver in different
cgroups in order to measure cgroup context switch overheads.

Users need to make sure the cgroups exist and accessible. The following
example should the effect of this change. Please don't forget taskset
before the perf bench to measure cgroup switches properly. Otherwise
each task would run on a different CPU and generate cgroup switches
regardless of this change.

# perf stat -e context-switches,cgroup-switches \
> taskset -c 0 perf bench sched pipe -l 10000 > /dev/null

Performance counter stats for 'taskset -c 0 perf bench sched pipe -l 10000':

20,001 context-switches
2 cgroup-switches

0.053449651 seconds time elapsed

0.011286000 seconds user
0.041869000 seconds sys

# perf stat -e context-switches,cgroup-switches \
> taskset -c 0 perf bench sched pipe -l 10000 -G AAA,BBB > /dev/null

Performance counter stats for 'taskset -c 0 perf bench sched pipe -l 10000 -G AAA,BBB':

20,001 context-switches
20,001 cgroup-switches

0.052768627 seconds time elapsed

0.006284000 seconds user
0.046266000 seconds sys

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Link: https://lore.kernel.org/r/20231017202342.1353124-1-namhyung@kernel.org

perf tools: Cast (struct timeval).tv_sec when printing

The musl-libc [1] defines (struct timeval).tv_sec as a 'long long' for
arm and other architectures. The default build having a '-Wformat' flag,
not casting the field when printing prevents from building perf.

This patch casts the (struct timeval).tv_sec fields to the expected
format.

[1] git://git.musl-libc.org/musl

Signed-off-by: Pierre Gondois <Pierre.Gondois@arm.com>
Acked-by: Jiri Olsa <jolsa@redhat.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Douglas.raillard@arm.com
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lore.kernel.org/lkml/20210224182410.5366-1-Pierre.Gondois@arm.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

perf tools: Remove util.h from where it is not needed

Check that it is not needed and remove, fixing up some fallout for
places where it was only serving to get something else.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: https://lkml.kernel.org/n/tip-9h6dg6lsqe2usyqjh5rrues4@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

perf tools: Remove needless builtin.h include directives

Now that builtin.h isn't included by any other header, we can check
where it is really needed, i.e. we can remove it and be sure that it
isn't being obtained indirectly.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: https://lkml.kernel.org/n/tip-mn7jheex85iw9qo6tlv26hb2@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

perf tools: Remove perf.h from source files not needing it

With the movement of lots of stuff out of perf.h to other headers we
ended up not needing it in lots of places, remove it from those places.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: https://lkml.kernel.org/n/tip-c718m0sxxwp73lp9d8vpihb4@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

License cleanup: add SPDX GPL-2.0 license identifier to files with no license

Many source files in the tree are missing licensing information, which
makes it harder for compliance tools to determine the correct license.

By default all files without license information are under the default
license of the kernel, which is GPL version 2.

Update the files which contain no license information with the 'GPL-2.0'
SPDX license identifier. The SPDX identifier is a legally binding
shorthand, which can be used instead of the full boiler plate text.

This patch is based on work done by Thomas Gleixner and Kate Stewart and
Philippe Ombredanne.

How this work was done:

Patches were generated and checked against linux-4.14-rc6 for a subset of
the use cases:
- file had no licensing information it it.
- file was a */uapi/* one with no licensing information in it,
- file was a */uapi/* one with existing licensing information,

Further patches will be generated in subsequent months to fix up cases
where non-standard license headers were used, and references to license
had to be inferred by heuristics based on keywords.

The analysis to determine which SPDX License Identifier to be applied to
a file was done in a spreadsheet of side by side results from of the
output of two independent scanners (ScanCode & Windriver) producing SPDX
tag:value files created by Philippe Ombredanne. Philippe prepared the
base worksheet, and did an initial spot review of a few 1000 files.

The 4.13 kernel was the starting point of the analysis with 60,537 files
assessed. Kate Stewart did a file by file comparison of the scanner
results in the spreadsheet to determine which SPDX license identifier(s)
to be applied to the file. She confirmed any determination that was not
immediately clear with lawyers working with the Linux Foundation.

Criteria used to select files for SPDX license identifier tagging was:
- Files considered eligible had to be source code files.
- Make and config files were included as candidates if they contained >5
lines of source
- File already had some variant of a license header in it (even if <5
lines).

All documentation files were explicitly excluded.

The following heuristics were used to determine which SPDX license
identifiers to apply.

- when both scanners couldn't find any license traces, file was
considered to have no license information in it, and the top level
COPYING file license applied.

For non */uapi/* files that summary was:

SPDX license identifier # files
---------------------------------------------------|-------
GPL-2.0 11139

and resulted in the first patch in this series.

If that file was a */uapi/* path one, it was "GPL-2.0 WITH
Linux-syscall-note" otherwise it was "GPL-2.0". Results of that was:

SPDX license identifier # files
---------------------------------------------------|-------
GPL-2.0 WITH Linux-syscall-note 930

and resulted in the second patch in this series.

- if a file had some form of licensing information in it, and was one
of the */uapi/* ones, it was denoted with the Linux-syscall-note if
any GPL family license was found in the file or had no licensing in
it (per prior point). Results summary:

SPDX license identifier # files
---------------------------------------------------|------
GPL-2.0 WITH Linux-syscall-note 270
GPL-2.0+ WITH Linux-syscall-note 169
((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause) 21
((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) 17
LGPL-2.1+ WITH Linux-syscall-note 15
GPL-1.0+ WITH Linux-syscall-note 14
((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause) 5
LGPL-2.0+ WITH Linux-syscall-note 4
LGPL-2.1 WITH Linux-syscall-note 3
((GPL-2.0 WITH Linux-syscall-note) OR MIT) 3
((GPL-2.0 WITH Linux-syscall-note) AND MIT) 1

and that resulted in the third patch in this series.

- when the two scanners agreed on the detected license(s), that became
the concluded license(s).

- when there was disagreement between the two scanners (one detected a
license but the other didn't, or they both detected different
licenses) a manual inspection of the file occurred.

- In most cases a manual inspection of the information in the file
resulted in a clear resolution of the license that should apply (and
which scanner probably needed to revisit its heuristics).

- When it was not immediately clear, the license identifier was
confirmed with lawyers working with the Linux Foundation.

- If there was any question as to the appropriate license identifier,
the file was flagged for further research and to be revisited later
in time.

In total, over 70 hours of logged manual review was done on the
spreadsheet to determine the SPDX license identifiers to apply to the
source files by Kate, Philippe, Thomas and, in some cases, confirmation
by lawyers working with the Linux Foundation.

Kate also obtained a third independent scan of the 4.13 code base from
FOSSology, and compared selected files where the other two scanners
disagreed against that SPDX file, to see if there was new insights. The
Windriver scanner is based on an older version of FOSSology in part, so
they are related.

Thomas did random spot checks in about 500 files from the spreadsheets
for the uapi headers and agreed with SPDX license identifier in the
files he inspected. For the non-uapi files Thomas did random spot checks
in about 15000 files.

In initial set of patches against 4.14-rc6, 3 files were found to have
copy/paste license identifier errors, and have been fixed to reflect the
correct identifier.

Additionally Philippe spent 10 hours this week doing a detailed manual
inspection and review of the 12,461 patched files from the initial patch
version early this week with:
- a full scancode scan run, collecting the matched texts, detected
license ids and scores
- reviewing anything where there was a license detected (about 500+
files) to ensure that the applied SPDX license was correct
- reviewing anything where there was no detection but the patch license
was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied
SPDX license was correct

This produced a worksheet with 20 files needing minor correction. This
worksheet was then exported into 3 different .csv files for the
different types of files to be modified.

These .csv files were then reviewed by Greg. Thomas wrote a script to
parse the csv files and add the proper SPDX tag to the file, in the
format that the file expected. This script was further refined by Greg
based on the output to detect more types of files automatically and to
distinguish between header and source .c files (which need different
comment types.) Finally Greg ran the script using the .csv files to
generate the patches.

Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

perf tools: Remove unused 'prefix' from builtin functions

We got it from the git sources but never used it for anything, with the
place where this would be somehow used remaining:

static int run_builtin(struct cmd_struct *p, int argc, const char **argv)
{
prefix = NULL;
if (p->option & RUN_SETUP)
prefix = NULL; /* setup_perf_directory(); */

Ditch it.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/n/tip-uw5swz05vol0qpr32c5lpvus@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

perf bench sched-pipe: Use linux/time64.h, USEC_PER_SEC

Following kernel practices.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/n/tip-wgfu1h1pnw8lc919o2tan58y@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

perf subcmd: Create subcmd library

Move the subcommand-related files from perf to a new library named
libsubcmd.a.

Since we're moving files anyway, go ahead and rename 'exec_cmd.*' to
'exec-cmd.*' to be consistent with the naming of all the other files.

Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/c0a838d4c878ab17fee50998811612b2281355c1.1450193761.git.jpoimboe@redhat.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

perf tools: Avoid build splat for syscall numbers with uclibc

This is due to duplicated unistd inclusion (via uClibc headers + kernel headers)
Also seen on ARM uClibc based tools

------- ARC build ---------->8-------------

CC util/evlist.o
In file included from
~/arc/k.org/arch/arc/include/uapi/asm/unistd.h:25:0,
from util/../perf-sys.h:10,
from util/../perf.h:15,
from util/event.h:7,
from util/event.c:3:
~/arc/k.org/include/uapi/asm-generic/unistd.h:906:0:
warning: "__NR_fcntl64" redefined [enabled by default]
#define __NR_fcntl64 __NR3264_fcntl
^
In file included from
~/arc/gnu/INSTALL_1412-arc-2014.12-rc1/arc-snps-linux-uclibc/sysroot/usr/include/sys/syscall.h:24:0,
from util/../perf-sys.h:6,
----------------->8-------------------

------- ARM build ---------->8-------------

CC FPIC plugin_scsi.o
In file included from util/../perf-sys.h:9:0,
from util/../perf.h:15,
from util/cache.h:7,
from perf.c:12:
~/arc/k.org/arch/arm/include/uapi/asm/unistd.h:28:0:
warning: "__NR_restart_syscall" redefined [enabled by default]
In file included from
~/buildroot/host/usr/arm-buildroot-linux-uclibcgnueabi/sysroot/usr/include/sys/syscall.h:25:0,
from util/../perf-sys.h:6,
from util/../perf.h:15,
from util/cache.h:7,
from perf.c:12:
~/buildroot/host/usr/arm-buildroot-linux-uclibcgnueabi/sysroot/usr/include/bits/sysnum.h:17:0:
note: this is the location of the previous definition
----------------->8-------------------

Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
Cc: Alexey Brodkin <Alexey.Brodkin@synopsys.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1421156604-30603-4-git-send-email-vgupta@synopsys.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

perf bench sched: Add --threaded option

Allow the measurement of thread versus process context switch
performance.

The default stays at 'process' based measurement, like lmbench's lat_ctx
benchmark.

Sample output:

comet:~/tip/tools/perf> taskset 1 ./perf bench sched pipe
# Running sched/pipe benchmark...
# Executed 1000000 pipe operations between two processes

Total time: 4.138 [sec]

4.138729 usecs/op
241620 ops/sec
comet:~/tip/tools/perf> taskset 1 ./perf bench sched pipe --threaded
# Running sched/pipe benchmark...
# Executed 1000000 pipe operations between two threads

Total time: 3.667 [sec]

3.667667 usecs/op
272652 ops/sec

Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Namhyung Kim <namhyung.kim@lge.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Arnaldo Carvalho de Melo <acme@infradead.org>
Link: http://lkml.kernel.org/r/20130917114256.GA31159@gmail.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

perf tools: Use __maybe_used for unused variables

perf defines both __used and __unused variables to use for marking
unused variables. The variable __used is defined to
__attribute__((__unused__)), which contradicts the kernel definition to
__attribute__((__used__)) for new gcc versions. On Android, __used is
also defined in system headers and this leads to warnings like: warning:
'__used__' attribute ignored

__unused is not defined in the kernel and is not a standard definition.
If __unused is included everywhere instead of __used, this leads to
conflicts with glibc headers, since glibc has a variables with this name
in its headers.

The best approach is to use __maybe_unused, the definition used in the
kernel for __attribute__((unused)). In this way there is only one
definition in perf sources (instead of 2 definitions that point to the
same thing: __used and __unused) and it works on both Linux and Android.
This patch simply replaces all instances of __used and __unused with
__maybe_unused.

Signed-off-by: Irina Tirdea <irina.tirdea@intel.com>
Acked-by: Pekka Enberg <penberg@kernel.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Namhyung Kim <namhyung.kim@lge.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Steven Rostedt <rostedt@goodmis.org>
Link: http://lkml.kernel.org/r/1347315303-29906-7-git-send-email-irina.tirdea@intel.com
[ committer note: fixed up conflict with a116e05 in builtin-sched.c ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

perf bench: fix assert when NDEBUG is defined

When NDEBUG is defined, the assert macro will be expanded to nothing.
Some assert calls used in perf are also including some functionality
(e.g. system calls), not only validity checks. Therefore, if NDEBUG is
defined, this functionality will be removed along with the assert. Perf
also defines BUG_ON based on assert, so it has the same problem.

Define BUG_ON so that the condition will be executed when NDEBUG is
defined. Replace the assert statements that have these side effects
with BUG_ON.

For defining BUG_ON, use "if (cond) {}" insted of "if (cond) ;" because
in the latter case build fails with "error: suggest braces around empty
body in an ‘if’ statement [-Werror=empty-body]"

Suggested-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Irina Tirdea <irina.tirdea@intel.com>
Reviewed-by: Namhyung Kim <namhyung@kernel.org>
Reviewed-by: Pekka Enberg <penberg@kernel.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Namhyung Kim <namhyung.kim@lge.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Steven Rostedt <rostedt@goodmis.org>
Link: http://lkml.kernel.org/r/1347082551-2394-1-git-send-email-irina.tirdea@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

perf tool: Fix gcc 4.6.0 issues

GCC 4.6.0 in Fedora rawhide turned up some compile errors in tools/perf
due to the -Werror=unused-but-set-variable flag.

I've gone through and annotated some of the assignments that had side
effects (ie: return value from a function) with the __used annotation,
and in some cases, just removed unused code.

In a few cases, we were assigning something useful, but not using it in
later parts of the function.

kyle@dreadnought:~/src% gcc --version
gcc (GCC) 4.6.0 20110122 (Red Hat 4.6.0-0.3)

Cc: Ingo Molnar <mingo@redhat.com>
LKML-Reference: <20110124161304.GK27353@bombadil.infradead.org>
Signed-off-by: Kyle McMartin <kyle@redhat.com>
[ committer note: Fixed up the annotation fixes, as that code moved recently ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

perf bench: fix spello

Fix spello in user message.

Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>,
Cc: Paul Mackerra <paulus@samba.org>s
LKML-Reference: <20100331113056.2c7df509.randy.dunlap@oracle.com>
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>

perf sched: Fix build failure on sparc

Here, tvec->tv_usec is "unsigned int" not "unsigned long".

Since the type is different on every platform, it's probably
best to just use long printf formats and cast.

Signed-off-by: David S. Miller <davem@davemloft.net>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <20091213.235622.53363059.davem@davemloft.net>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

perf bench: Add "all" pseudo subsystem and "all" pseudo suite

This patch adds a new "all" pseudo subsystem and an "all" pseudo
suite. These are for testing all subsystem and its all suite, or
all suite of one subsystem.

(This patch also contains a few trivial comment fixes for
bench/* and output style fixes. I judged that there are no
necessity to make them into individual patch.)

Example of use:

| % ./perf bench sched all # Test all suites of sched subsystem
| # Running sched/messaging benchmark...
| # 20 sender and receiver processes per group
| # 10 groups == 400 processes run
|
| Total time: 0.414 [sec]
|
| # Running sched/pipe benchmark...
| # Extecuted 1000000 pipe operations between two tasks
|
| Total time: 10.999 [sec]
|
| 10.999317 usecs/op
| 90914 ops/sec
|
| % ./perf bench all # Test all suites of all subsystems
| # Running sched/messaging benchmark...
| # 20 sender and receiver processes per group
| # 10 groups == 400 processes run
|
| Total time: 0.420 [sec]
|
| # Running sched/pipe benchmark...
| # Extecuted 1000000 pipe operations between two tasks
|
| Total time: 11.741 [sec]
|
| 11.741346 usecs/op
| 85169 ops/sec
|
| # Running mem/memcpy benchmark...
| # Copying 1MB Bytes from 0x7ff33e920010 to 0x7ff3401ae010 ...
|
| 808.407437 MB/Sec

Signed-off-by: Hitoshi Mitake <mitake@dcl.info.waseda.ac.jp>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <1260691319-4683-1-git-send-email-mitake@dcl.info.waseda.ac.jp>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

perf bench: Improve sched-pipe.c with more comfortable output

This patch improves sched-pipe.c with more comfortable output.

Change points are comment style description and
formatting numerical values and its units.

Example:

| % ./perf bench sched pipe
| # Running sched/pipe benchmark...
| # Extecuted 1000000 pipe operations between two tasks
|
| Total time:5.822 [sec]
|
| 5.822553 usecs/op
| 171745 ops/sec

Signed-off-by: Hitoshi Mitake <mitake@dcl.info.waseda.ac.jp>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
LKML-Reference: <1257865442-20252-3-git-send-email-mitake@dcl.info.waseda.ac.jp>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

perf bench: Modify builtin-pipe.c for processing common options

This patch modifies builtin-pipe.c for processing common
options. The first option added is "--format".
Users of perf bench will be able to specify output style by
--format.

Usage example:

% ./perf bench sched pipe # with no style specify
(executing 1000000 pipe operations between two tasks)

Total time:5.855 sec
5.855061 usecs/op
170792 ops/sec

% ./perf bench --format=simple sched pipe # specified simple
5.988

Signed-off-by: Hitoshi Mitake <mitake@dcl.info.waseda.ac.jp>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
LKML-Reference: <1257808802-9420-5-git-send-email-mitake@dcl.info.waseda.ac.jp>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>

perf bench: Fix bench/sched-pipe.c to wait for child process

Ingo reported this small 'perf bench sched pipe' output problem:

| $ ./perf bench sched pipe
| (executing 1000000 pipe operations between two tasks)
|
| Total time:4.898 sec
| $ 4.898586 usecs/op
| 204140 ops/sec
|
| the shell prompt came back before the usecs/op and ops/sec line
| was printed. Process teardown race, lack of wait() or so?

This caused by lack of calling waitpid() by parent process,
so I added it.

Signed-off-by: Hitoshi Mitake <mitake@dcl.info.waseda.ac.jp>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Kosina <jkosina@suse.cz>
LKML-Reference: <1257737465-7546-1-git-send-email-mitake@dcl.info.waseda.ac.jp>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

perf bench: Add sched-pipe.c: Benchmark for pipe() system call

This patch adds bench/sched-pipe.c.

bench/sched-pipe.c is a benchmark program
to measure performance of pipe() system call.
This benchmark is based on pipe-test-1m.c by Ingo Molnar:

http://people.redhat.com/mingo/cfs-scheduler/tools/pipe-test-1m.c

Example of use:

% perf bench sched pipe
(executing 1000000 pipe operations between two tasks)

Total time:4.499 sec
4.499179 usecs/op
222262 ops/sec

% perf bench sched pipe -s -l 1000
0.015

Signed-off-by: Hitoshi Mitake <mitake@dcl.info.waseda.ac.jp>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: fweisbec@gmail.com
Cc: Jiri Kosina <jkosina@suse.cz>
LKML-Reference: <1257381097-4743-4-git-send-email-mitake@dcl.info.waseda.ac.jp>
Signed-off-by: Ingo Molnar <mingo@elte.hu>