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From "Roy T. Fielding" <field...@gbiv.com>
Subject Re: svn commit: r109866 - /httpd/httpd/trunk/modules/loggers/mod_log_config.c
Date Mon, 06 Dec 2004 22:29:25 GMT
-1 (veto) -- the message is copied to a single buffer for the write
because that is the only way to guarantee an atomic append under
Unix without locks, thus preventing multiple children from scribbling
over each other's log entries.  Please revert this change ASAP.

....Roy

On Dec 5, 2004, at 12:58 PM, Paul Querna wrote:

> Joe Orton wrote:
>> On Sun, Dec 05, 2004 at 07:05:23AM -0000, Paul Querna wrote:
>>> Author: pquerna
>>> Date: Sat Dec  4 23:05:23 2004
>>> New Revision: 109866
>>>
>>> URL: http://svn.apache.org/viewcvs?view=rev&rev=109866
>>> Log:
>>> mod_log_config.c: Use iovecs to write the log line to eliminate a 
>>> memcpy
>> IIRC, writev'ing several small blocks to a file is actually generally
>> more expensive than doing a memcpy in userspace and calling write.  
>> Did
>> you benchmark this to be faster/better/...?
>
> I did a local mini-benchmark of write w/ memcpy vs writev... and they 
> came out to almost exactly the same on average with small sets of 
> data.
>
> -Paul
>
>


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