Re: cfq misbehaving on 2.6.11-1.14_FC3

[spaminos-ker]

--- Jens Axboe <axboe@xxxxxxx> wrote:
> Journalled file systems will behave worse for this, because it has to
> tend to the journal as well. Can you try mounting that partition as ext2
> and see what numbers that gives you?

I did the tests again on a partition that I could mkfs/mount at will.

On ext3, I get about 33 seconds average latency.

And on ext2, as predicted, I have latencies in average of about 0.4 seconds.

I also tried reiserfs, and it gets about 22 seconds latency.

As you pointed out, it seems that there is a flow in the way IO queues and
journals (that are in some ways queues as well), interact in the presence of
flushes.

Nicolas

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