Messages in this thread | | | Date | Tue, 24 Apr 2001 19:19:41 -0400 | From | Ignacio Monge <> | Subject | Re: PIO disk writes using 100% system time and performing poorly with VIA vt82c686b on kernels 2.2 & 2.4 |
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Hi. 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 Master Read Cycle IRDY: 0ws Master Write Cycle IRDY: 0ws BM IDE Status Register Read Retry: yes Max DRDY Pulse Width: No limit -----------------------Primary IDE-------Secondary IDE------ Read DMA FIFO flush: yes yes End Sector FIFO flush: no no Prefetch Buffer: no no Post Write Buffer: no no Enabled: yes yes Simplex only: no no 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. I don't know why. Maybe VIA vt82c686a doesn't support it? 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.
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. Luck.
PS: in cat /proc/ide/via I see "Cable Type: 40w 40w"... Is it right? I have a 80w cable, not 40.
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