Re: Performance figure for sx8 driver

[kallol@nucleodyne.com]

The following steps have been used to reproduce the problem.
I am not sure how hdparm worked on non-scsi or non-ide device.

> $ cat /proc/diskstats
>    1    0 ram0 0 0 0 0 0 0 0 0 0 0 0
>    1    1 ram1 0 0 0 0 0 0 0 0 0 0 0
>    1    2 ram2 0 0 0 0 0 0 0 0 0 0 0
>    1    3 ram3 0 0 0 0 0 0 0 0 0 0 0
>    1    4 ram4 0 0 0 0 0 0 0 0 0 0 0
>    1    5 ram5 0 0 0 0 0 0 0 0 0 0 0
>    1    6 ram6 0 0 0 0 0 0 0 0 0 0 0
>    1    7 ram7 0 0 0 0 0 0 0 0 0 0 0
>    1    8 ram8 0 0 0 0 0 0 0 0 0 0 0
>    1    9 ram9 0 0 0 0 0 0 0 0 0 0 0
>    1   10 ram10 0 0 0 0 0 0 0 0 0 0 0
>    1   11 ram11 0 0 0 0 0 0 0 0 0 0 0
>    1   12 ram12 0 0 0 0 0 0 0 0 0 0 0
>    1   13 ram13 0 0 0 0 0 0 0 0 0 0 0
>    1   14 ram14 0 0 0 0 0 0 0 0 0 0 0
>    1   15 ram15 0 0 0 0 0 0 0 0 0 0 0
>  160   64 sx8/2 1 0 8 10 0 0 0 0 0 10 10
>  160   65 sx8/2p1 0 0 0 0
>  160  128 sx8/4 1 0 8 20 0 0 0 0 0 20 20
>  160  129 sx8/4p1 0 0 0 0
>  160  192 sx8/6 1 0 8 20 0 0 0 0 0 20 20
>  160  193 sx8/6p1 0 0 0 0
>    3    0 hda 1 0 8 0 0 0 0 0 0 0 0
>    3    1 hda1 0 0 0 0
>
>  $ mknod /dev/sda b 160 64
> $ mknod /dev/sdb b 160 128
> $ mknod /dev/sdc b 160 192
>  $ ./hdparm -t /dev/sda &
> $./hdparm -t /dev/sdb
................

Quoting kallol@nucleodyne.com:

> Hello Jeff,
>            Changing CARM_MAX_Q to 30 and upgrading the firmware to
> firmware(BIOS-1.00.0.37, Firmware-1.3.19) does not help.
>
> Anything else to try?
>
> Kallol
>
> Quoting Jeff Garzik <jgarzik@pobox.com>:
>
> > kallol@nucleodyne.com wrote:
> > > Does anyone have performace figure for sx8 driver which is for 
> > > promise SATAII150
> > > 8 port PCI-X adapter?
> > >
> > > Someone reports that on a platform with sx8 driver, multiple hdparms on
> > > different disks those are connected to the same adapter (there are 
> > > 8 ports) can
> > > not get more than 45MB/sec in total, whereas a SCSI based driver 
> > > for the same
> > > adapter gets around 150MB/sec.
> > >
> > > Any comment on this?
> >
> > Known.  Early firmwares for SX8 had problems that forced the driver to
> > limit the number of outstanding requests, for all ports, to _one_.
> >
> > Later firmwares have fixed this, but the driver has not been updated to
> > detect newer(fixed) firmwares.
> >
> > You may update drivers/block/sx8.c as such:
> >
> > - CARM_MAX_Q              = 1,               /* one command at a time */
> > + CARM_MAX_Q              = 30,              /* 30 commands at a time */
> >
> > if you have a newer firmware, to obtain much better performance.
> >
> > 	Jeff
> >
> >
> > -
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