performance issues: linux aic7xxx, 29160, Radion IFT-7200

[Eric Dantan Rzewnicki]

Justin, 

Thanks for getting back to me so quickly. 

Lowering the queue depth was actually my first guess as well. The poor
results I posted earlier, and again trimmed down here, are with Rev
6.2.5 set to a depth of 8 for tagged command queuing. 

As I understood it based on the configure options and output from the
driver via dmesg (both of which I may have _mis_-understood) the old
driver leaves tagged queuing disabled by default. I attempted to turn
off tagged command queuing by passing aic7xxx=tag_info:{{255,255}} at
the boot prompt. This resulted in tagged queuing depth being set to 253.
So I suspect the 255 value is not correct. I got it from
linux/drivers/scsi/README.aic7xxx. But, it's not clear to me if this
file refers to the current driver or the old one as it was last updated
in 2000 by Doug Ledford.

Is it possible, or even a good idea, to turn off TCQ?

Thanks again for your help on this.

-Eric Rz.

newbunyan:~# uname -r
2.4.18-aic7xxx-6.2.5

scsi0 : Adaptec AIC7XXX EISA/VLB/PCI SCSI HBA DRIVER, Rev 6.2.5
        <Adaptec 29160 Ultra160 SCSI adapter>
        aic7892: Ultra160 Wide Channel A, SCSI Id=7, 32/253 SCBs

  Vendor: SEAGATE   Model: ST318405LW        Rev: 5063
  Type:   Direct-Access                      ANSI SCSI revision: 03
(scsi0:A:0): 160.000MB/s transfers (80.000MHz DT, offset 63, 16bit)
  Vendor: IFT       Model: IFT-7200          Rev: 0144
  Type:   Direct-Access                      ANSI SCSI revision: 04
(scsi0:A:1): 160.000MB/s transfers (80.000MHz DT, offset 62, 16bit)
scsi0:A:0:0: Tagged Queuing enabled.  Depth 8


newbunyan:~# hdparm -t /dev/sdb

/dev/sdb:
 Timing buffered disk reads:  64 MB in  4.16 seconds = 15.38 MB/sec


"Justin T. Gibbs" wrote:
> 
> >Hello Justin,
> >
> >We are experiencing some performance issues with our external Radion
> >raid device and the "new" aic7xxx drivers in linux kernel 2.4.x when
> >compared with either 2.2.x kernels or 2.4.x kernels using the
> >aic7xxx_old driver. Our hardware:
> 
> My guess is that your Radion does not like high queue depths.  Try
> lowering the queue depth of the aic7xxx driver (8 was the default
> in the old driver, the new driver will do up to 254).
> 
> --
> Justin
> 
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