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Re: Speed-optimized file copy
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Re: Speed-optimized file copy


  • Subject: Re: Speed-optimized file copy
  • From: "Quinn \"The Eskimo!\"" <email@hidden>
  • Date: Thu, 21 Jul 2011 10:56:20 +0100

On 20 Jul 2011, at 20:28, Wim Lewis wrote:

> Now that I think about it, all of these optimizations amount to implementing readahead in user space. The question then is whether Darwin's readahead is operational even when F_NOCACHE is in effect [...]

Setting no-cache will disable read ahead.  When you think about this, it's pretty obvious why: if there's no caching going on, there's no where to read ahead to.  So if no cache is set, one would want to implement read ahead in user space, which brings us back to the producer/consumer approach I outlined in my first email.

S+E
--
Quinn "The Eskimo!"                    <http://www.apple.com/developer/>
Apple Developer Relations, Developer Technical Support, Core OS/Hardware


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  • Follow-Ups:
    • Re: Speed-optimized file copy
      • From: "Quinn \"The Eskimo!\"" <email@hidden>
References: 
 >Speed-optimized file copy (From: Stevo Brock <email@hidden>)
 >Re: Speed-optimized file copy (From: Wim Lewis <email@hidden>)
 >Re: Speed-optimized file copy (From: "Quinn \"The Eskimo!\"" <email@hidden>)
 >Re: Speed-optimized file copy (From: Wim Lewis <email@hidden>)

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