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Re: [Xen-users] Very slow drives, I/O - DMA issues?

To: xen-users@xxxxxxxxxxxxxxxxxxx
Subject: Re: [Xen-users] Very slow drives, I/O - DMA issues?
From: "Lonny Selinger" <lonny@xxxxxxxxxxxxxxxxxxxxxxxx>
Date: Tue, 20 Feb 2007 16:54:48 -0600 (CST)
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> First here are my hdparm results:
> # hdparm -tT /dev/hda
> /dev/hda:
>  Timing cached reads:   1476 MB in  2.00 seconds = 737.13 MB/sec
>  Timing buffered disk reads:   10 MB in  3.44 seconds =   2.90 MB/sec
> # hdparm -tT /dev/hdb
> /dev/hdb:
>  Timing cached reads:   1480 MB in  2.01 seconds = 738.15 MB/sec
>  Timing buffered disk reads:    6 MB in  3.15 seconds =   1.91 MB/sec

Follow up ... here are the drives using the stock non-xen kernel ... I have
some dmesg to weed through and figure out what driver I need.

# hdparm -tT /dev/hda

 Timing cached reads:   1396 MB in  2.00 seconds = 697.06 MB/sec
 Timing buffered disk reads:  142 MB in  3.02 seconds =  47.03 MB/sec
[root@localhost ~]# hdparm -tT /dev/hdb

 Timing cached reads:   1448 MB in  2.00 seconds = 722.66 MB/sec
 Timing buffered disk reads:  136 MB in  3.01 seconds =  45.13 MB/sec

Uniform Multi-Platform E-IDE driver Revision: 7.00alpha2
ide: Assuming 33MHz system bus speed for PIO modes; override with idebus=xx
NFORCE2: IDE controller at PCI slot 0000:00:09.0
NFORCE2: chipset revision 162
NFORCE2: not 100% native mode: will probe irqs later
NFORCE2: BIOS didn't set cable bits correctly. Enabling workaround.
NFORCE2: 0000:00:09.0 (rev a2) UDMA133 controller
    ide0: BM-DMA at 0xf000-0xf007, BIOS settings: hda:DMA, hdb:DMA
    ide1: BM-DMA at 0xf008-0xf00f, BIOS settings: hdc:DMA, hdd:DMA
Probing IDE interface ide0...
hda: WDC WD400JB-00ENA0, ATA DISK drive
hdb: WDC WD2000JB-32FUA0, ATA DISK drive
Using cfq io scheduler
ide0 at 0x1f0-0x1f7,0x3f6 on irq 14
Probing IDE interface ide1...
hdd: HL-DT-ST GCE-8523B, ATAPI CD/DVD-ROM drive
ide1 at 0x170-0x177,0x376 on irq 15
Probing IDE interface ide2...
Probing IDE interface ide3...
Probing IDE interface ide4...
Probing IDE interface ide5...
hda: max request size: 128KiB
hda: 78165360 sectors (40020 MB) w/8192KiB Cache, CHS=65535/16/63, UDMA(100)
hda: cache flushes not supported
 hda: hda1 hda2
hdb: max request size: 1024KiB
hdb: 390721968 sectors (200049 MB) w/8192KiB Cache, CHS=24321/255/63, UDMA(100)
hdb: cache flushes supported
 hdb: hdb1
hdc: ATAPI 48X DVD-ROM drive, 512kB Cache, UDMA(33)
Uniform CD-ROM driver Revision: 3.20
hdd: ATAPI 52X CD-ROM CD-R/RW drive, 2048kB Cache, UDMA(33)

Possibly the top line?

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