Am Mittwoch, 3. August 2011 schrieb Jeff Moyer: > Martin Steigerwald <Martin@xxxxxxxxxxxx> writes: > > - ioengine=libaio > > - direct=1 > > - and then due to direct I/O alignment requirement: bsrange=2k-16k > > > > So I now also fully understand that ioengine=sync just refers to the > > synchronous nature of the system calls used, not on whether the I/Os > > are issued synchronously via sync=1 or by circumventing the page > > cache via direct=1 > > > > Attached are results that bring down IOPS on read drastically! I > > first let sequentiell.job write out the complete 2 gb with random > > data and then ran the iops.job. > > If you want to measure the maximum iops, then you should consider > driving iodepths > 1. Assuming you are testing a sata ssd, try using a > depth of 64 (twice the NCQ depth). Yes, I thought about that too, but then also read about the "recommendation" to use an iodepth of one in a post here: http://www.spinics.net/lists/fio/msg00502.html What will be used in regular workloads - say Linux desktop on an SSD here? I would bet that Linux uses what it can get? What about server workloads like mail processing on SAS disks or fileserver on SATA disks and such like? Twice of merkaba:~> hdparm -I /dev/sda | grep -i queue Queue depth: 32 * Native Command Queueing (NCQ) ? Why twice? Thanks, -- Martin 'Helios' Steigerwald - http://www.Lichtvoll.de GPG: 03B0 0D6C 0040 0710 4AFA B82F 991B EAAC A599 84C7 -- To unsubscribe from this list: send the line "unsubscribe fio" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
