Re: 2.6.21.1 - 97% wait time on IDE operations

["Julio M. Merino Vidal" <jmerino@ac.upc.edu>]

On 26/05/2007, at 15:05, Tommy Vercetti wrote:

> Hi folks,
>
> I was trying to get answer to my question around, but no one knows.
> I do have DMA turned on, etc, yet - on extensive harddrive  
> operations wait
> time is 90+% , which means that machine is waiting, rather than doing
> something meanwhile. (I guess).
> Can someone describe to me , in more detail why is that happening,  
> and what
> steps should I consider to avoid it ? I couldn't find any answers  
> that would
> have help me on net.

I see in your other post that you have a laptop disk drive and, based  
on its specs, it is a 4200RPM one.  Laptop drives are incredibly slow  
for random disk access -- I have one and hate it with passion... even  
though it is slightly better (5400RPM)...

You mention that you are doing expensive disk operations.  If these  
involve a lot of disk seeks (such as, for example, a "cvs update" on  
a large source tree), disk performance will be very very poor and any  
other operation you attempt on it will be slow as well.  These kind  
of drives are the major bottleneck of current laptop machines, in my  
opinion.

(I just wanted to make this clear wrt the hardware.  I do not know if  
Linux is also involved or not.)

--
Julio M. Merino Vidal <jmerino@ac.upc.edu>


-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/