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From Dean Gaudet <>
Subject Re: Want to add file caching to Apache
Date Fri, 21 Nov 1997 02:49:52 GMT

On Thu, 20 Nov 1997, Brian Behlendorf wrote:

> >If you do add file caching to apache, make sure to leave a way not to do
> >this on NT.  File caching comes for free when you use the Win32 functions
> >like TransmitFile, etc that we have talked about using for Apache 2.0.  To
> >manage the file cache you setup a file handle cache, closing file handles
> >when you do not need the file in cache and keeping open the ones you do want
> >in cache.  Implementing a separate file cache would move the file cache out
> >of the kernel into user space and would force copies of the file date, which
> >is very CPU expensive...

Are file handles a limited resource under win32?  If so then this bites. 
At least with open()/mmap()/close() under unix you can fill many many Mb
of your process space with file data.  More than you would be able to keep
around open filehandles for typically.  But I suppose the same trick might
work for win32 using its similar-to-mmap stuff.  Remember that web
documents average 6k (from the point of view of an http proxy cache... 
some day I should get off my butt and get real data off of one of wired's


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