Re: PDC20265 IDE controller trouble

[Andre Hedrick]

Well blame that on the folks that are not taking kernel code that will
allow you to solve this problem.  Linus is the number one offender.

Regards,

Andre Hedrick
CEO/President, LAD Storage Consulting Group
Linux ATA Development
Linux Disk Certification Project

On Sat, 15 Dec 2001, Rene Rebe wrote:

> Hi.
> 
> This is on a AMD K6-2 350Mhz, 128MB RAM, on a Ali Aladin5 based Gigabyte board
> 3x IBM DTLA 40GB discs on a Promisse TX2 Ultra 100 in a PCI slot.
> 
> Single transfer to one disk:
> server1:~ # hdparm -tT /dev/ide/host2/bus0/target0/lun0/disc
> 
> /dev/ide/host2/bus0/target0/lun0/disc:
>  Timing buffer-cache reads:   128 MB in  2.12 seconds = 60.38 MB/sec
>  Timing buffered disk reads:  64 MB in  2.86 seconds = 22.38 MB/sec
> 
> Dual transfer to disks on sperated channels (values per disk):
> server1:~ # hdparm -tT /dev/ide/host2/bus0/target0/lun0/disc
> 
> /dev/ide/host2/bus0/target0/lun0/disc:
>  Timing buffer-cache reads:   128 MB in  4.13 seconds = 30.99 MB/sec
>  Timing buffered disk reads:  64 MB in  4.66 seconds = 13.73 MB/sec
> 
> Dual transfer to disks on the same channel (values per dics):
> server1:~ # hdparm -tT /dev/ide/host2/bus0/target1/lun0/disc
> 
> /dev/ide/host2/bus0/target1/lun0/disc:
>  Timing buffer-cache reads:   128 MB in  4.44 seconds = 28.83 MB/sec
>  Timing buffered disk reads:  64 MB in  8.36 seconds =  7.66 MB/sec
> 
> Hey! This might be the cause for the slowdown I reported in another
> Raid5 / ReiserFS thread!!
> 
> Is this an general IDE issue or is some queueing code in the kernel
> rather bad/slow for this task???
> 
> On Sat, 15 Dec 2001 18:35:29 +0100 (MET)
> Jurij Smakov <[e-mail]> wrote:
> 
> > Hi!
> > 
> > Recently I've got an Asus TUSL2 motherboard, which has an extra Promise
> > IDE RAID controller with a PDC20265 chip. I've connected two IBM 60 GB
> > disks to it (one disk per channel). I am using kernel 2.4.17-pre8
> > (with CONFIG_BLK_DEV_PDC202XX=y and with/without CONFIG_PDC202XX_BURST=y),
> > which nicely detects the extra controller and both disks, hde and hdg. If
> > I test the writing and reading speed (hdparm -t, dd if=/dev/zero of=test
> > ...) separately for each disk, I get the expected figures, like 36-37
> > MB/sec for reading, about 30 MB/sec for writing. If, however, I try to
> > write simultaneously to both disks, the performance drops drastically. The
> > rate for writing is then something like 3.5 MB/sec (!). I wonder if anyone
> > have seen anything like that or might have any ideas on how to solve the
> > problem.
> > 
> > Suspecting the hardware, I've posted this message to
> > comp.os.linux.hardware first, but no one have seen such a behaviour. I
> > have also tried different sets of IDE cables.
> > 
> > Best regards and TIA,
> > 
> > 
> > Jurij.
> > 
> > P.S. Please cc responses to me, because I'm not on the list.
> > 
> > -
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> 
> 
> 
> k33p h4ck1n6
>   René
> 
> -- 
> René Rebe (Registered Linux user: #248718 <http://counter.li.org>)
> 
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