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

[Avi Kivity]

Ingo Molnar wrote:
> * Avi Kivity <avi@xxxxxxxxxx> 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

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