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From: Paulo Marques <pmarques@grupopie.com>
To: Hamie <hamish@travellingkiwi.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>,
	Russell King <rmk+lkml@arm.linux.org.uk>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: ide-cs using 100% CPU
Date: Mon, 09 Aug 2004 10:57:41 +0100	[thread overview]
Message-ID: <41174A95.3050705@grupopie.com> (raw)
In-Reply-To: <4115EC6C.5040608@travellingkiwi.com>

Hamie wrote:
> Alan Cox wrote:
> 
>> On Gwe, 2004-08-06 at 20:33, Hamie wrote:
>>  
>>
>>> Is 100% CPU not excessive? IIRC my PIII-750 used to use less CPU 
>>> doing the same job as quick, or even slightly faster...
>>>   
>>
>>
>> PCMCIA IDE is PIO only so it burns CPU. This is one case where
>> hyperthreading is nice. Cardbus IDE is a lot better but very little
>> exists and we don't currently support hotplug IDE controllers.
>>
>>  
>>
> 
> Ah right. But would a CF memory card be cardbus anyway?

I've never seen a CF card that supported DMA (and I've worked with 
several brands). Compact Flash cards have several modes of operation and 
only one of this modes is "IDE-compatible".

> 
>>> And should it not use system CPU rather than user CPU?
>>>   
>>
>>
>> Yes - but figure out please if the kernel or userspace is getting that
>> wrong ;)
>>
>>  
>>
> 
> My apologies. It was gkrellm leading me up the garden path on that 
> one... Copying about 100MB from a 512MB CF card (25+ photos from my 
> camera) vmstat 5 reports 4% usercpu, 96% system cpu. And the response on 
> the system is sluggish to say the least. (Moving the pointer in X is 
> painful :). gkrell meanwhile on it's cpu graph shows about 30% system, 
> and the rest as userCPU. No idea why, I guess till I find out I'll just 
> regard gkrellm's cpu graph as a waste of space (To differentiate system 
> & user cpu anyway :).

I think this is more of a scheduler/priorities problem. Maybe all the 
work that is being done with staircase / low-latency will help you on 
this :)

-- 
Paulo Marques - www.grupopie.com
"In a world without walls and fences who needs windows and gates?"

  parent reply	other threads:[~2004-08-09  9:57 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2004-07-18  9:30 ide-cs using 100% CPU Hamie
2004-08-06 19:27 ` Russell King
2004-08-06 19:33   ` Hamie
2004-08-06 19:38     ` Russell King
2004-08-07 17:55       ` Hamie
2004-08-07 22:26     ` Alan Cox
2004-08-08  9:03       ` Hamie
2004-08-08 15:24         ` Alan Cox
2004-08-09  9:57         ` Paulo Marques [this message]
2004-08-09 12:32           ` P
2004-08-09 20:11       ` Bill Davidsen
     [not found] <fa.j0leddb.okcbor@ifi.uio.no>
     [not found] ` <fa.goasld9.1q1kb05@ifi.uio.no>
2004-08-07 19:21   ` Robert Hancock
2004-08-08 15:24     ` Hamie
     [not found] <fa.hhjr2f2.1ql2t80@ifi.uio.no>
     [not found] ` <fa.ggacpdl.26on0d@ifi.uio.no>
2004-08-08 19:32   ` Robert Hancock

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