| Here's some details from demsg before and after. This is the
Compaq card.
ncr0: <ncr 53c825 fast10 wide scsi> port 0xe400-0xe4ff
mem 0xfebfef00-0xfebfefff irq 15 at device 15.0 on pci0
This is the Adaptec card.
ahc0: <Adaptec 2940 Ultra2 SCSI adapter> port 0xe800-0xe8ff
mem 0xfebff000-0xfebfffff irq 10 at device 13.0 on pci0
aic7890/91: Wide Channel A, SCSI Id=7, 32/255 SCBs
Note that the Compaq was "wide scsi" but the Adaptec is "Ultra2".
That makes quite a difference to the disk performance. As you can see in the
following dmesg extracts.
These are the SCSI drives under the Compaq:
da0: <SEAGATE ST318436LW 0010> Fixed Direct Access SCSI-3 device
da0: 20.000MB/s transfers (10.000MHz, offset 8, 16bit),
Tagged Queueing Enabled
da0: 17522MB (35885168 512 byte sectors: 255H 63S/T 2233C)
da1 at ncr0 bus 0 target 1 lun 0
da1: <SEAGATE ST318436LW 0010> Fixed Direct Access SCSI-3 device
da1: 20.000MB/s transfers (10.000MHz, offset 8, 16bit),
Tagged Queueing Enabled
da1: 17522MB (35885168 512 byte sectors: 255H 63S/T 2233C)
These are the SCSI drives under the Adaptec::
da0 at ahc0 bus 0 target 0 lun 0
da0: <SEAGATE ST318436LW 0010> Fixed Direct Access SCSI-3 device
da0: 40.000MB/s transfers (20.000MHz, offset 31, 16bit),
Tagged Queueing Enabled
da0: 17522MB (35885168 512 byte sectors: 255H 63S/T 2233C)
da1 at ahc0 bus 0 target 1 lun 0
da1: <SEAGATE ST318436LW 0010> Fixed Direct Access SCSI-3 device
da1: 40.000MB/s transfers (20.000MHz, offset 31, 16bit),
Tagged Queueing Enabled
da1: 17522MB (35885168 512 byte sectors: 255H 63S/T 2233C)
As you can see, the transfer rate under Ultra2 is twice as fast as wide scsi.
That should make a difference to the kernel compiling. |