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This gets rid of oddities such as:
perf bench futex hash -t -4
perf: calloc: Cannot allocate memory
Runtime (and many more) are equally busted, i.e. run for bogus amounts of
time. Just use the abs, instead of, for example errorring out.
Committer note:
After the patch:
$ perf bench futex hash -t -4
# Running 'futex/hash' benchmark:
Run summary [PID 10178]: 4 threads, each operating on 1024 [private] futexes for 10 secs.
[thread 0] futexes: 0x34f9fa0 ... 0x34faf9c [ 4702208 ops/sec ]
[thread 1] futexes: 0x34fb140 ... 0x34fc13c [ 4707020 ops/sec ]
[thread 2] futexes: 0x34fc2e0 ... 0x34fd2dc [ 4711526 ops/sec ]
[thread 3] futexes: 0x34fd480 ... 0x34fe47c [ 4709683 ops/sec ]
Averaged 4707609 operations/sec (+- 0.04%), total secs = 10
$
Signed-off-by: Davidlohr Bueso <[email protected]>
Tested-by: Arnaldo Carvalho de Melo <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>
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Sebastian noted that overhead for worker thread ops (throughput)
accounting was producing 'perf' to appear in the profiles, consuming a
non-trivial (i.e. 13%) amount of CPU.
This is due to cacheline bouncing due to the increment of w->ops.
We can easily fix this by just working on a local copy and updating the
actual worker once done running, and ready to show the program summary.
There is no danger of the worker being concurrent, so we can trust that
no stale value is being seen by another thread.
This also gets rid of the unnecessary cache alignment hack; its not
worth it.
Reported-by: Sebastian Andrzej Siewior <[email protected]>
Signed-off-by: Davidlohr Bueso <[email protected]>
Acked-by: Sebastian Andrzej Siewior <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>
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It popped up in perf testing that the worker consumes some amount of
CPU. It boils down to the increment of `ops` which causes cache line
bouncing between the individual threads.
This patch aligns the struct by 256 bytes to ensure that not a cache
line is shared among CPUs. 128 byte is the x86 worst case and grep says
that L1_CACHE_SHIFT is set to 8 on s390.
Signed-off-by: Sebastian Andrzej Siewior <[email protected]>
Cc: Davidlohr Bueso <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>
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Since these files use __maybe_unused, and that is defined in
linux/compiler.h, include it.
Cc: Adrian Hunter <[email protected]>
Cc: David Ahern <[email protected]>
Cc: Davidlohr Bueso <[email protected]>
Cc: Hitoshi Mitake <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Namhyung Kim <[email protected]>
Cc: Wang Nan <[email protected]>
Link: http://lkml.kernel.org/n/[email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>
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We should try avoiding that perf.h header, it includes way too much
stuff, making it difficult to use things like setting _GNU_SOURCE only
on a small set of headers.
Cc: Adrian Hunter <[email protected]>
Cc: David Ahern <[email protected]>
Cc: Davidlohr Bueso <[email protected]>
Cc: Hitoshi Mitake <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Namhyung Kim <[email protected]>
Cc: Wang Nan <[email protected]>
Link: http://lkml.kernel.org/n/[email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>
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Cc: David Ahern <[email protected]>
Cc: Davidlohr Bueso <[email protected]>
Cc: Hitoshi Mitake <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Namhyung Kim <[email protected]>
Cc: Wang Nan <[email protected]>
Link: http://lkml.kernel.org/n/[email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>
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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 <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Namhyung Kim <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Link: http://lkml.kernel.org/r/c0a838d4c878ab17fee50998811612b2281355c1.1450193761.git.jpoimboe@redhat.com
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>
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Unlike futex-hash, requeuing and wakeup benchmarks do not support shared
futexes, limiting the usefulness of the programs. Correct this, and
allow using the local -S parameter. The default remains using private
futexes.
Signed-off-by: Davidlohr Bueso <[email protected]>
Cc: Davidlohr Bueso <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>
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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 <[email protected]>
Acked-by: Darren Hart <[email protected]>
Cc: Aswin Chandramouleeswaran <[email protected]>
Cc: Darren Hart <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Jason Low <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Scott J Norton <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Waiman Long <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>
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