Messages in this thread | | | Date | Wed, 25 Apr 2001 00:12:36 +0200 | From | Vojtech Pavlik <> | Subject | Re: PIO disk writes using 100% system time and performing poorly with VIA vt82c686b on kernels 2.2 & 2.4 |
| |
On Tue, Apr 24, 2001 at 07:19:41PM -0400, Ignacio Monge wrote:
> I have VIA686a too and a UDMA100 hard disk. > This is my cat /proc/ide/via: > > ----------VIA BusMastering IDE Configuration---------------- > Driver Version: 3.23 > South Bridge: VIA vt82c686a > Revision: ISA 0x22 IDE 0x10 > Highest DMA rate: UDMA66 > BM-DMA base: 0xb800 > PCI clock: 33MHz > -----------------------Primary IDE-------Secondary IDE------ > Enabled: yes yes > Cable Type: 40w 40w > -------------------drive0----drive1----drive2----drive3----- > Transfer Mode: DMA UDMA PIO PIO > Address Setup: 30ns 30ns 120ns 120ns > Cmd Active: 90ns 90ns 480ns 480ns > Cmd Recovery: 30ns 30ns 480ns 480ns > Data Active: 90ns 90ns 330ns 330ns > Data Recovery: 30ns 30ns 270ns 270ns > Cycle Time: 120ns 60ns 600ns 600ns > Transfer Rate: 16.5MB/s 33.0MB/s 3.3MB/s 3.3MB/s > > As you can see, l use UDMA66 instead UDMA100.
You use UDMA33 dor your second drive and MWDMA16 for your first. Check your BIOS UDMA enable settings.
> I don't know why. Maybe VIA vt82c686a doesn't support it?
Yes, it supports modes only up to 66 MB/sec.
> I have answering in this list a days ago about this problem. but none seems to have a question. Like you, my system goes down when I try to compile something (I have a 394 Mb of RAM and a 1 Ghz processor). > Although, my hdparm output is this: > /dev/hde2: > Timing buffer-cache reads: 128 MB in 0.79 seconds =162.03 MB/sec > Timing buffered disk reads: 64 MB in 2.44 seconds = 26.23 MB/sec > and sometime looks better.
26 megabytes per second is quite surprising in your setup
> I don't know is this is a problem with the VIA kernel driver or not. But the system doesn't seem to work fine since 2.4.2 or 2.4.1 kernel. I hope (plz!) this problem will be fixed in future.
You can disable the VIA driver.
> PS: in cat /proc/ide/via I see "Cable Type: 40w 40w"... Is it right? I have a 80w cable, not 40.
Check your BIOS settings, if you have disabled UDMA in the BIOS, the driver can't detect the cable. If that doesn't work, use "ide0=ata66" on the kernel command line.
-- Vojtech Pavlik SuSE Labs - 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/
| |