Re: IDE DMA disabled with via82cxxx on kernels >= 2.5.35

[Andrew Morton]

On Mon January 13 2003 18:49, [e-mail] wrote:
>
> 2.4.20-pre3-jam1:
> 
> /dev/hda:
>  Timing buffer-cache reads:   128 MB in  0.70 seconds =182.86 MB/sec
>  Timing buffered disk reads:  64 MB in  2.07 seconds = 30.92 MB/sec
> 
> 2.5.53-mm1
> 
> /dev/hda:
>  Timing buffer-cache reads:   128 MB in  7.20 seconds = 17.78 MB/sec
>  Timing buffered disk reads:  64 MB in 19.66 seconds =  3.26 MB/sec

2.5.53-mm1 had a dud patch in it which made part of the kernel think HZ=100,
other parts think HZ=1000, depending on whether the .c file happened to
include config.h before including param.h.

Hence your nice 10x discrepancy.