[Haskell-cafe] whatever happened to sendFile?

Brandon S. Allbery KF8NH allbery at ece.cmu.edu
Wed Aug 13 15:17:49 EDT 2008

On 2008 Aug 13, at 15:04, Brandon S. Allbery KF8NH wrote:

> On 2008 Aug 13, at 15:01, Chaddaï Fouché wrote:
>> 2008/8/13 Jason Dusek <jason.dusek at gmail.com>:
>>> I found an old lib for it:
>>>  http://www.haskell.org/ghc/docs/6.0/html/unix/System.Sendfile.html
>>> Hoogle turns up nothing, though.
>> That don't sound very useful... Maybe when we only had String it was
>> much more performant for big transfert, but now we can recode this in
>> one short line of ByteString code and get the same performance as C.
> sendfile() is actually a system call, not a library function.

I should clarify:  what sendfile() is supposed to optimize isn't  
writing large strings, or even the user<->kernel roundtrips; it's an  
optimization to the kernel network stack (network buffer management,  
to be specific).  Web servers use it to serve static content (e.g.  
icons, images, stylesheets) because it significantly reduces system  

brandon s. allbery [solaris,freebsd,perl,pugs,haskell] allbery at kf8nh.com
system administrator [openafs,heimdal,too many hats] allbery at ece.cmu.edu
electrical and computer engineering, carnegie mellon university    KF8NH

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