Re: Page Cache writeback too slow, SSD/noop scheduler/ext2

From: Jos Houtman
Date: Tue Mar 31 2009 - 10:10:59 EST



>> There another question I have: does the writeback go through the io
>> scheduler? Because no matter the io scheduler or the tuning done, the
>> writeback algorithm totally starves the reads.
>
> I noticed this annoying writes-starve-reads problem too. I'll look into it.

Thanks

>
>> Is there anything I can do about this behaviour by creating a better
>> interleaving of the reads and writes?
>
> I guess it should be handled in the generic block io layer. Once we
> solved the writes-starve-reads problem, the bursty-writeback behavior
> becomes a no-problem for SSD.

Yeah this was the part where I figured the io-schedulers kicked in, but
obviously I was wrong :P.

If I can do anything more to help this along, let me know.


Thanks

Jos



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