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Re: TRIM details

To: karn@xxxxxxxx
Subject: Re: TRIM details
From: Matthias Schniedermeyer <ms@xxxxxxx>
Date: Fri, 7 Jan 2011 10:17:20 +0100
Cc: xfs@xxxxxxxxxxx
In-reply-to: <20110107091120.GA6634@xxxxxxx>
References: <4D2686ED.7000304@xxxxxxxxxxxx> <20110107091120.GA6634@xxxxxxx>
User-agent: Mutt/1.5.19 (2009-01-05)
On 07.01.2011 10:11, Matthias Schniedermeyer wrote:
> On 06.01.2011 19:22, Phil Karn wrote:
> 
> > Just have the drive interpret an ordinary write of all 0's to any LBA as
> > an implicit "unmap" indication for that LBA. As long as the drive
> 
> The drive would have to look into each written sector in the off chance 
> that it might be 0, that's a lot of electrons you have to burn for not 
> much gain. And that's ignoring the performance side, doing such a check 
> on each incoming write would be expensive at best.

Altough, after thinking about it a little more. Doing a Population count 
in the controller while the data comes in over the wire can't be that 
expensive.





Bis denn

-- 
Real Programmers consider "what you see is what you get" to be just as 
bad a concept in Text Editors as it is in women. No, the Real Programmer
wants a "you asked for it, you got it" text editor -- complicated, 
cryptic, powerful, unforgiving, dangerous.

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