ext2fs now extremely slow

[Doug Barton]

On 11/08/2010 09:43, Aditya Sarawgi wrote:
> On Wed, Nov 03, 2010 at 05:43:26PM -0700, Doug Barton wrote:

>> Regarding stability, sometimes (but not always) when I'm doing the above
>> listed disk-intensive things on an otherwise idle system I've had the
>> system lock up. Not panic, not reboot, just wedge. I'm running X when
>> this happens, so I'm not 100% sure that the disk activity is the
>> culprit, but it seems very suspicious. Yesterday was a very bad day, I
>> had to do 3 tries to get all the way through a buildworld/kernel, mostly
>> because the last 2 crashes resulted in my /usr/src (which is actually
>> /home/svn/head) and /usr/obj (/home/obj-9) directories getting corrupted
>> respectively. Today (running r214694) has actually been quite good,
>> although I haven't tried a buildworld yet.
>>
>
> I am not sure if this is the right use case for ext2fs

Can you expand on that? What about it do you see as problematic?

>>> You can test Zheng's preallocation patch for ext2fs, there is a
>>> serious lack of testers for that.
>>
>> I would be happy to do that, but my reading of this thread last month
>> didn't produce a clear "try this version of the patch" neon sign.
>> Various people referred to suggestions, updates, etc. If someone could
>> provide a URL for the right patch to try, as well as a suggestion for
>> benchmarking methodology, I'll be glad to do so.
>>
>
> I have attached the patch.

Thanks for that. I'm curious though whether this is the latest version 
of the patch with the suggested improvements from earlier in this thread?

> Some primitive testing like copying files,
> untaring etc and comparing with the existing ext2fs will do. If you
> are looking to do a full fledged benchmarking then I would suggest
> iozone, blogbench, dbench etc.

Sorry, I am not a filesystem person, so if you want me to do any real 
benchmarking you're going to have to give me details ... Install this 
program, run this test, etc.

Meanwhile I finally got around to setting up my 8.1-RELEASE partition on 
this same system and particularly with cvsup it's very noticeable that 
ext2fs in -current is MUCH slower than in RELENG_8. I'll do some before 
and after tests on -current, then I'll do the same thing on 8.1 and see 
how the numbers compare.


Doug

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