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Date:      Sun, 4 Nov 2007 01:21:53 -0400
From:      "Josh Carroll" <josh.carroll@gmail.com>
To:        "Jeff Roberson" <jroberson@chesapeake.net>
Cc:        freebsd-performance@freebsd.org
Subject:   Re: ULE vs. 4BSD in RELENG_7
Message-ID:  <8cb6106e0711032221i2ecf1d59ge82f368d4162a827@mail.gmail.com>
In-Reply-To: <20071103133711.Q544@10.0.0.1>
References:  <8cb6106e0710230902x4edf2c8eu2d912d5de1f5d4a2@mail.gmail.com> <8cb6106e0710251925s2db0117cvcb67321b08d7b2a1@mail.gmail.com> <20071102102331.G544@10.0.0.1> <8cb6106e0711021306w10c48a15s99eab526064ac814@mail.gmail.com> <20071102150028.R544@10.0.0.1> <8cb6106e0711021839i4714bdfbh74d412b3e14e808@mail.gmail.com> <8cb6106e0711031227t1e829969s2e6062e1db5167af@mail.gmail.com> <20071103121921.M544@10.0.0.1> <8cb6106e0711031416l4183e2beueb87fade0d56f504@mail.gmail.com> <20071103133711.Q544@10.0.0.1>

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> Josh, thanks for your help so far.  This has been very useful.

You're welcome, glad to help! Thanks for the effort and the patch.

> Any testing you can run this through is appreciated.  Anyone else lurking
> in this thread who would like to is also welcome to report back findings.

Here are a few benchmarks comparing ULE and the patched ULE. I
experimented in changing the slice_min value from 2 to 4, in case that
might be useful info for you. Hopefully that helps a bit, but if not
it's just a few minutes of CPU time wasted :)

Sysbench results:
# threads    slice=7     slice=13     slice_min=4      slice_min=2
4                2265.67    2250.36      2261.71            2297.08
8                2300.25    2310.02      2306.79            2313.61
12              2269.54    2304.04      2296.54            2279.73
16              2249.26    2252.04      2260.53            2245.76

It looks like with the default minimum (2), the performance for systat
is better with 4 and 8 threads (on a 4 core system), but worse for 12
and 16 threads.

Here are the results for ffmpeg (-threads 8):

slice=7      slice=13       slice_min=4         slice_min=2
1:37.00      1:39.09         1:38.12                1:38.06

The patch definitely improves things there, though not quite as good
as using a slice value of 7. But it does improve things. So it
slightly improves things for ffmpeg and also slightly increases the
performance of sysbench/MySQL (with 8 threads).

I also ran through buildworld for both slice_min of 2 and 4, and here
are the results, again with ULE as a base line:

slice=7      slice=13       slice_min=4         slice_min=2
13:40.56    13:44.28       13:46.64              13:45.80

So buildworld performance is about the same as with the default ULE
and default slice value.

Thanks,
Josh



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