On Wed, 19 Mar 2008 18:08:07 -0700 Jeremy Higdon <jeremy@xxxxxxx> wrote: > (cc's added. It matters) > On Thu, Mar 20, 2008 at 10:16:54AM +1100, David Chinner wrote: > > 4p ia64, 24GB RAM, 2.6.25-rc3, qla1280, 15krpm scsi disk. > > > > Direct I/O: > > > > dgc@budgie:~/xfstests$ sudo dd if=/dev/zero of=/dev/sdb6 bs=1024k count=1024 oflag=direct > > 1024+0 records in > > 1024+0 records out > > 1073741824 bytes (1.1 GB) copied, 27.8974 s, 38.5 MB/s > > > > Doing approximately 80 512k I/os per second (disk bandwidth). > > > > Buffered I/O: > > > > dgc@budgie:~/xfstests$ sudo dd if=/dev/zero of=/dev/sdb6 bs=1024k count=4096 > > 4096+0 records in > > 4096+0 records out > > 4294967296 bytes (4.3 GB) copied, 427.872 s, 10.0 MB/s > > How big is sdb6? How many '2's do you see in > > factor `cat /sys/block/sdb/sdb6/size` There have always been problems with thsi and I'm not sure that anyone cared enough about buffered writes to blockdevs to get to the bottom of them. I assume you aren't running i386 highmem... > > I also suspect that CTQ has not been set up correctly on this > > kernel, because: > > > > $ cat /sys/block/sdb/device/queue_depth > > 3 > > $ ls -l /sys/block/sdb/device/queue_depth > > -r--r--r-- 1 root root 0 Mar 20 09:59 /sys/block/sdb/device/queue_depth > > $ > > > > It appears to be hard coded to 3 and can't be changed.... > > That's a bug in the qla1280 driver. I thought that had gotten fixed. > It's looking at the wrong mailbox register after setting device parameters. > Was there a patch anywhere? -- To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
