Re: [RESEND][RFC] BFQ I/O Scheduler

From: Paolo Valente
Date: Thu Apr 17 2008 - 11:18:44 EST


Aaron Carroll ha scritto:
You still end up with reduced global throughput as
you've shown in the ``Short-term time guarantees'' table. It is an
interesting case though... since the lower performance is not though fault
of the process it doesn't seem fair to ``punish'' it.
Just a note about that table. The lower aggregate throughput of bfq is due to the fact that, because of the higher number of movies being read, a higher percentage of not-that-profitable accesses is being performed under bfq wrt to cfq. As shown in the complete logs of the aggregate throughput in the raw results, the aggregate throughput with bfq and cfq is practically the same when the number of movies is the same.
The figure in the "Aggregate throughput" subsection is probably best suited for a comparison of the performance of the two schedulers with sequential accesses under the same conditions (the figure refers to the 2, 128 MB long, files, but we got virtually the same results in all the other tests).
I do agree on that these experiments should be repeated with different (faster) devices.

Paolo

-- Aaron




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