# Any reason to change io scheduler on a desktop system?

## Purrkur

I was just compiling my kernel and I noticed that three io schedulers are built in. The anticipatory io scheduler is used as default so I searched for some information to see if anybody had opinions on what scheduler is best for a desktop system but I didn't come up with all that much. 

So the question is, has anybody looked into this in any detail for a desktop system? Will I gain anything from using the deadline or cfq schedulers? I can't say that I am having any problems or difficulties with io performance so this is just a question because these choices have made me curious  :Smile: 

Fwiw, the information on these schedulers in the kernel say that the cfq should be good for desktops because of it's politically correct behaviour (that is, all processes are equal), but they don't say anything about how the desktop behaviour will change , what kind of behaviour to expect or why it is better to have such a scheduler.

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## luisfelipe

Well, there's no better way to find out than testing them on your own. 

I have tried changing io schedulers once, but didn't notice too much difference.

Gonna do some tests again on my next kernel update and if I get something 

interesting I'll post here.

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## Purrkur

 *luisfelipe wrote:*   

> Well, there's no better way to find out than testing them on your own. 

 

I will certainly do that if time allows. The reason why I wrote this post was to ask for feedback because if everybody went ahead and tested then I guess it would be like reinventing the wheel now wouldn't it?  :Wink:  I guess the first step for testing would be to figure out ways to test the schedulers in order to see what they are made of and I haven't come that far yet.

 *luisfelipe wrote:*   

> I have tried changing io schedulers once, but didn't notice too much difference.
> 
> Gonna do some tests again on my next kernel update and if I get something 
> 
> interesting I'll post here.

 

Thanks.

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## luisfelipe

OK, this is completely offtopic, but are you certain that the "end up somewhere else" quote is from

Alfred Adler ?? Wikiquote says it's from Yogi Berra, and doesn't list anything similar to it on their 

Alfred Adler page. I really like that quote, and I never saw it being attributed to Adler, that's why

I'm asking it.

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## Purrkur

 *luisfelipe wrote:*   

> OK, this is completely offtopic, but are you certain that the "end up somewhere else" quote is from
> 
> Alfred Adler ?? 

 

Off topic indeed  :Smile:   I wasn't around to hear Adler say it but if you google for the quote and "adler" then you'll find plenty of references to adler and this saying. I can't be 100% certain but the place I got it from (can't remember where) said it was from him and I didn't want to change that reference.

See here and [url=http://www.quoteworld.org/author.php?thetext=Alfred+Adler+(1870-1937)]here[/url] and here and here for at least four references that should be credible.

Now how about that scheduler??  :Smile: 

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## nephros

Well I have taken the habit to NOT enable CFQ on my optical drives, always use AS.

I have not any test data or words from experts for this, but my reasoning is that data on CDs/DVDs is highly contiguous and transfer better if read consecutively and not interrupted by reads from other devices.

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