Doron Shoham wrote:
Bart Van Assche wrote:
On Tue, Mar 11, 2008 at 8:40 AM, Doron Shoham <dorons@xxxxxxxxxxxx> wrote:
sgp_dd if=/dev/sg1 of=/dev/null bs=512 bpt=128 thr=8 time=1 count=5M dio=1
time to transfer data was 2.236290 secs, 1200.36 MB/sec
5242880+0 records in
5242880+0 records out
Direct IO requested but incomplete 40960 times
What does it mean "Direct IO requested but incomplete 40960 times"?
And what could be the reason for this?
The man page of sgp_dd states that the parameter specified to bs must
be the block size of the physical device. You can query the block size
of a SCSI device with e.g. the scsi_readcap command:
$ scsi_readcap /dev/sda
sg_readcap /dev/sda
Read Capacity results:
Last logical block address=625142447 (0x2542eaaf), Number of blocks=625142448
Logical block length=512 bytes
Hence:
Device size: 320072933376 bytes, 305245.3 MiB, 320.07 GB
Bart.
Hi,
sg_readcap /dev/sdb
Read Capacity results:
Last block address=3221225471 (0xbfffffff), Number of blocks=3221225472
Block size=512 bytes
Hence:
Device size: 1649267441664 bytes, 1572864.0 MiB, 1649.27 GB
The block size is 512 as I used in the sgp_dd command.
The problem is just when using dio=1, without it it works ok.
Doron,
Try reducing the bpt value (say to 64 or 32). To see more of
what might be the problem add 'verbose=<n>' to the command
line (and reduce the count to stop being flooded with
debug messages).
Doug Gilbert
--
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
