Re: IO scheduler based IO controller V10

From: Ulrich Lukas
Date: Thu Sep 24 2009 - 22:20:35 EST


Vivek Goyal wrote:
> Notes:
> - With vanilla CFQ, random writers can overwhelm a random reader.
> Bring down its throughput and bump up latencies significantly.


IIRC, with vanilla CFQ, sequential writing can overwhelm random readers,
too.

I'm basing this assumption on the observations I made on both OpenSuse
11.1 and Ubuntu 9.10 alpha6 which I described in my posting on LKML
titled: "Poor desktop responsiveness with background I/O-operations" of
2009-09-20.
(Message ID: 4AB59CBB.8090907@xxxxxxxxxxxxxxxxx)


Thus, I'm posting this to show that your work is greatly appreciated,
given the rather disappointig status quo of Linux's fairness when it
comes to disk IO time.

I hope that your efforts lead to a change in performance of current
userland applications, the sooner, the better.


Thanks
Ulrich
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