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 <jurij.smakov@telia.com> 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.
> >
> > -
> > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
> > the body of a message to majordomo@vger.kernel.org
> > More majordomo info at http://vger.kernel.org/majordomo-info.html
> > Please read the FAQ at http://www.tux.org/lkml/
> >
>
>
>
> k33p h4ck1n6
> René
>
> --
> René Rebe (Registered Linux user: #248718 <http://counter.li.org>)
>
> eMail: rene.rebe@gmx.net
> rene@rocklinux.org
>
> Homepage: http://www.tfh-berlin.de/~s712059/index.html
>
> Anyone sending unwanted advertising e-mail to this address will be
> charged $25 for network traffic and computing time. By extracting my
> address from this message or its header, you agree to these terms.
> -
> To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at http://vger.kernel.org/majordomo-info.html
> Please read the FAQ at http://www.tux.org/lkml/
>
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
This archive was generated by hypermail 2b29 : Sat Dec 15 2001 - 21:00:30 EST