Re: 2.6.1-rc1 [resend]

[Paolo Ornati <ornati _at_ xxxxxxxx>]

On Wednesday 31 December 2003 17:31, Ed Sweetman wrote:
> Paolo Ornati wrote:
> > On Wednesday 31 December 2003 16:20, you wrote:
> >>On Wednesday 31 December 2003 16:06, you wrote:
> >>>>What io scheduler are you using? Or, could you post /var/log/dmesg?
> >>
> >>On Wed, Dec 31, 2003 at 04:19:27PM +0100, Paolo Ornati wrote:
> >>>"dmesg" and "config" attached.
> >>
> >>Could you try this with elevator=deadline?
> >
> > ok, I have just tried...
> > I don't see any big difference.
>
> Wasn't it mentioned in another thread related to a drop in ide
> performance that there is possibly some bug in the ide code that ends up
> requiring you to set the readahead on all your devices to see the max
> performance of any one?
>
> set all the readaheads of all your ide devices to 8192  You should see
> the best peformance doing this.

No, I have just try it but I don't see any changes.

My question is about a strange change of "behaviour" in IDE performance 
changing readahead.

Here I report a new thing that I've noticed today:

Kernel 2.6.0:

o readahead up to 224:
when I run "hdparm -t /dev/hda" the HD LED light up... and after a while 
light down

o readahead > 224:
running "hdparm" the HD LED starts blinking... and then light down

The best performance are riched with values between 128 and 224 --> IOW when 
the HD led starts blinking the performance diminish...


Kernel 2.6.1-rc1:

the HD LED starts to blink with readahead = 16 !!!
Why?


BYE

-- 
	Paolo Ornati
	Linux v2.6.0

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