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Re: Missing APR_BUFFERED flag on file open?

From: Greg Hudson <ghudson_at_MIT.EDU>
Date: 2005-11-03 18:11:34 CET

On Thu, 2005-11-03 at 14:20 +0000, Julian Foad wrote:
> Hmm. What exactly is the benefit of this flag? Looking at the code, I see it
> causes APR to do its own buffering on top of what the C run-time library and/or
> OS already do.

APR doesn't use the C run-time library (in the sense of using stdio) to
access files; it uses direct OS calls, which are expensive when done in
many small chunks.

We used to have some noticable performance problems because we opened
files unbuffered and then did a bunch of small reads and writes for,
say, keyword translation. We added a bunch of buffered flags and things
got better. I'm not sure whether it matters for these 31 instances, but
it's entirely possible that we could noticeably improve performance for
some operation.

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Received on Thu Nov 3 18:14:45 2005

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