Re: 2.6.0 performance problems

[David B. Stevens]

Thomas,

Have you tried lowering the read ahead in 2.6 to 8.

I don't know what you are doing with your workload but it is possible 
that you are transferring useless data and clogging the plumbing a bit.

Cheers,
 Dave



Thomas Molina wrote:

> It certainly looks like DMA is enabled.  Under 2.4 I get:
>
> [root@lap root]# hdparm /dev/hda
>
> /dev/hda:
> multcount    = 16 (on)
> IO_support   =  1 (32-bit)
> unmaskirq    =  1 (on)
> using_dma    =  1 (on)
> keepsettings =  0 (off)
> readonly     =  0 (off)
> readahead    =  8 (on)
> geometry     = 2584/240/63, sectors = 39070080, start = 0
>
>
> Under 2.6  I get:
>
> [root@lap root]# hdparm /dev/hda
>
> /dev/hda:
> multcount    = 16 (on)
> IO_support   =  1 (32-bit)
> unmaskirq    =  1 (on)
> using_dma    =  1 (on)
> keepsettings =  0 (off)
> readonly     =  0 (off)
> readahead    = 256 (on)
> geometry     = 38760/16/63, sectors = 39070080, start = 0
>  


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