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SubjectRe: [RFC GIT PULL] perf/trace/lock optimization/scalability improvements
On Wed, Feb 03 2010, Frederic Weisbecker wrote:
> Hi,
>
> There are many things that happen in this patchset, treating
> different problems:
>
> - remove most of the string copy overhead in fast path
> - open the way for lock class oriented profiling (as
> opposite to lock instance profiling. Both can be useful
> in different ways).
> - remove the buffers muliplexing (less contention)
> - event injection support
> - remove violent lock events recursion (only 2 among 3, the remaining
> one is detailed below).
>
> Some differences, by running:
> perf lock record perf sched pipe -l 100000
>
> Before the patchset:
>
> Total time: 91.015 [sec]
>
> 910.157300 usecs/op
> 1098 ops/sec
>
> After this patchset applied:
>
> Total time: 43.706 [sec]
>
> 437.062080 usecs/op
> 2288 ops/sec

This does a lot better here, even if it isn't exactly stellar
performance. It generates a LOT of data:

root@nehalem:/dev/shm # time perf lock rec -fg ls
perf.data perf.data.old
[ perf record: Woken up 0 times to write data ]
[ perf record: Captured and wrote 137.224 MB perf.data (~5995421
samples) ]

real 0m3.320s
user 0m0.000s
sys 0m3.220s

Without -g, it has 1.688s real and 1.590s sys time.

So while this is orders of magnitude better than the previous patchset,
it's still not anywhere near lean. But I expect you know that, just
consider this a 'I tested it and this is what happened' report :-)

--
Jens Axboe



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