On Mon, Sep 14, 2009 at 12:51 PM, Vladislav Bolkhovitin <[email protected]> wrote: > Chris Worley, on 09/11/2009 11:50 PM wrote: >> >> I've definitely removed the switch/firmware from being the cause. >> >> I'm thinking the reason you can't repeat the test may be latency >> related. We get ~50usecs average latency (on small block sizes), >> which can't be achieved using regular SSD's (and rotating drives are >> nowhere close). Maybe a ramdisk would help repeat the issue. > > I think you should try to reproduce the problem with ramdisk or nullio. By > so you will eliminate possible influence of the SSD backend.
W/ 12GB RAM in the target, I created a 7GB ramdisk: mount -t ramfs -o size=7g ramfs /mnt/ dd if=/dev/zero of=/mnt/foo bs=1024k count=7000 echo "open ramdisk /mnt/foo" > /proc/scsi_tgt/vdisk/vdisk echo "add ramdisk 2" >/proc/scsi_tgt/groups/Default/devices Then, on the initiator, I tested it... and it hung during sequential 8KB block reads: fio --rw=read --bs=8k --numjobs=64 --iodepth=64 --sync=0 --direct=1 --randrepeat=0 \ --group_reporting --ioengine=libaio --filename=/dev/sde --name=test --loops=10000 --runtime=600 Note that I was running the SM on the target this time too. Thanks, Chris > > Vlad > _______________________________________________ general mailing list [email protected] http://lists.openfabrics.org/cgi-bin/mailman/listinfo/general To unsubscribe, please visit http://openib.org/mailman/listinfo/openib-general
