Re: regression - slow git rebase performance with 2.6.39-rcX kernel

[Zdenek Kabelac]

2011/4/12 Jens Axboe <jaxboe@xxxxxxxxxxxx>:
> On 2011-04-12 14:51, Pekka Enberg wrote:
>> Hi,
>>
>> [ Fixed your empty CC list. ]
>>
>> On Tue, Apr 12, 2011 at 3:45 PM, Zdenek Kabelac
>> <zdenek.kabelac@xxxxxxxxx> wrote:
>>> I'm noticing quite slower speed of my git rebase commands on my git
>>> tree compared with 2.6.38 kernel.
>>> I've  T61 with SSD disc drive, ext4 fs, and by default deadline disk
>>> io scheduler
>>> The counter showing the number of 'rebased' patches on top of master
>>> is going much slower.
>>> When I boot 2.6.38 kernel it's much faster.
>>>
>>> Is it a known problem - or do I need to make a bisect ?
>>
>> No, I don't think it's a known problem. Git bisect would be helpful,
>> obviously.
>
> Definitely, interesting. Bisect would help. I'll try a similar workload
> here and see if I see any differences. How big is your rebase, and what
> are the runtimes (approximately) on .38 vs .39-rc?
>

I've made just quick build with the small kernel without debug options
enable - and the time is then equal with 2.6.38. So the difference is
probably somewhere in debug build  -  I assume some debug option
slowed down between 2.6.38 - 2.6.39 significantly.

Zdenek
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