Re: [patch 00/15] CFS Bandwidth Control V6

From: Hidetoshi Seto
Date: Wed Jun 15 2011 - 20:58:16 EST


(2011/06/15 17:37), Hu Tao wrote:
> On Tue, Jun 14, 2011 at 04:29:49PM +0900, Hidetoshi Seto wrote:
>> (2011/06/14 15:58), Hu Tao wrote:
>>> Hi,
>>>
>>> I've run several tests including hackbench, unixbench, massive-intr
>>> and kernel building. CPU is Intel(R) Xeon(R) CPU X3430 @ 2.40GHz,
>>> 4 cores, and 4G memory.
>>>
>>> Most of the time the results differ few, but there are problems:
>>>
>>> 1. unixbench: execl throughout has about 5% drop.
>>> 2. unixbench: process creation has about 5% drop.
>>> 3. massive-intr: when running 200 processes for 5mins, the number
>>> of loops each process runs differ more than before cfs-bandwidth-v6.
>>>
>>> The results are attached.
>>
>> I know the score of unixbench is not so stable that the problem might
>> be noises ... but the result of massive-intr is interesting.
>> Could you give a try to find which piece (xx/15) in the series cause
>> the problems?
>
> After more tests, I found massive-intr data is not stable, too. Results
> are attached. The third number in file name means which patchs are
> applied, 0 means no patch applied. plot.sh is easy to generate png
> files.

(Though I don't know what the 16th patch of this series is, anyway)
I see that the results of 15, 15-1 and 15-2 are very different and that
15-2 is similar to without-patch.

One concern is whether this unstable of data is really caused by the
nature of your test (hardware, massive-intr itself and something running
in background etc.) or by a hidden piece in the bandwidth patch set.
Did you see "not stable" data when none of patches is applied?
If not, which patch makes it unstable?


Thanks,
H.Seto

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