Thomas Waldmann writes:
> Strange: I "only" got about the same value with 4 IBM DNES UW SCSI disks.
> A single DNES disk gives about 17MB/s bonnie - about 50% (?) more than the
> older DDRS disk can do - so I had expected a transfer rate of >35MB/s (the
> SCSI channels theoretically could provide 2 * 40MB/s).
>
> So why don't I see better throughput using the faster disks ?
This is what I get on an ASUS P2B-DS, dual PII 400, 7890 on board and
4 LVD DNES 9GB using raid 5 (chunksize 128, e2fs block size 4k):
-------Sequential Output-------- ---Sequential Input-- --Random--
-Per Char- --Block--- -Rewrite-- -Per Char- --Block--- --Seeks---
Machine MB K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU /sec %CPU
kamet 900 13283 81.1 30748 50.4 13205 44.1 15887 69.8 29649 39.6 282.4 3.5
Have you enabled tag queueing?
#cat /proc/scsi/aic7xxx/0
Adaptec AIC7xxx driver version: 5.1.17/3.2.4
Compile Options:
TCQ Enabled By Default : Enabled
AIC7XXX_PROC_STATS : Enabled
AIC7XXX_RESET_DELAY : 5
Adapter Configuration:
SCSI Adapter: Adaptec AIC-7890/1 Ultra2 SCSI host adapter
Ultra-2 LVD/SE Wide Controller
PCI MMAPed I/O Base: 0xe1800000
Adapter SEEPROM Config: SEEPROM found and used.
Adaptec SCSI BIOS: Enabled
IRQ: 15
SCBs: Active 0, Max Active 60,
Allocated 75, HW 32, Page 255
Interrupts: 7787851
BIOS Control Word: 0x18a6
Adapter Control Word: 0x1c5e
Extended Translation: Enabled
Disconnect Enable Flags: 0xffff
Ultra Enable Flags: 0x0000
Tag Queue Enable Flags: 0x001f
Ordered Queue Tag Flags: 0x001f
Default Tag Queue Depth: 12
Tagged Queue By Device array for aic7xxx host instance 0:
{0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}
Actual queue depth per device for aic7xxx host instance 0:
{12,12,12,12,12,1,1,1,1,1,1,1,1,1,1,1}
Dirk
