On Tue, Feb 27 2007, Avi Kivity wrote: > Ingo Molnar wrote: > >* Avi Kivity <[EMAIL PROTECTED]> 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.
Take a look at scsi-debug, it can do at least some of that. -- Jens Axboe - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
