Re: A quick fio test (was Re: [patch 00/13] Syslets, "Threadlets", generic AIO support, v3)

Avi Kivity
2007-02-27T16:17:20Z

Ingo Molnar wrote:
> * Avi Kivity <avi@argo.co.il> wrote:
>
>
>> But what about cpu usage? At these low levels, the cpu is probably
>> underutilized. It would be interesting to measure cpu time per I/O
>> request (or, alternatively, use an I/O subsystem that can saturate the
>> processors).
>>
>
> yeah - that's what testing on ramdisk (Jens') or on a loopback block
> device (mine) approximates to a certain degree.
>
>

Ramdisks or fully cached loopback return immediately, so cache thrashing
effects don't show up.

Maybe a device mapper delay target or nbd + O_DIRECT can insert delays
to make the workload more disk-like.

--
error compiling committee.c: too many arguments to function