[plug] hdparm troubles

[Bernd Felsche]

On Saturday 17 July 2004 11:14, Steve Boak wrote:

> I'm trying to optimise the hd performance on my Via C3 500MHz system, and
> wondering why I have such terrible performance with what I thought was a
> fairly good configuration.
>
> min:~# hdparm -X68 -c3 -m16 -d1 /dev/hda
> /dev/hda:
>  setting 32-bit IO_support flag to 3
>  setting multcount to 16
>  setting using_dma to 1 (on)
>  setting xfermode to 68 (UltraDMA mode4)
>  multcount    = 16 (on)
>  IO_support   =  3 (32-bit w/sync)
>  using_dma    =  1 (on)
>
> min:~# hdparm -Tt /dev/hda
> /dev/hda:
>  Timing buffer-cache reads:   192 MB in  2.03 seconds =  94.58 MB/sec
>  Timing buffered disk reads:   12 MB in  3.20 seconds =   3.75 MB/sec
>
> 3.75 MB/sec ???

> udma is enabled in the BIOS,
> 80-way cables installed,
> brand new WDC  WD800BB hd.
> What have I missed?

Seems like DMA isn't actually on. I get 5.64 MB/sec on my 933MHz C3
reading 64MB with a non-DMA drive in a generic Pentium 2.2.x
kernel... and 37.74 off a 7200rpm 80GB with UDMA on a C3-compiled
2.4.20(?) kernel.

Maybe the IDE chipset drivers aren't working.

Scary figures on this system;

/dev/hda:
 Timing buffer-cache reads:   128 MB in  0.32 seconds =400.00 MB/sec
 Timing buffered disk reads:  64 MB in  1.35 seconds = 47.41 MB/sec

Buffer-cache is very fast, but actual disk isn't very much quicker
than the Mini-ITX

-- 
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