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From Paul Querna <>
Subject Re: Per module LogLevel configuration
Date Mon, 28 Dec 2009 09:02:01 GMT
On Sun, Dec 27, 2009 at 11:08 PM, William A. Rowe Jr.
<> wrote:
> Dan Poirier wrote:
>> Looking at log_error_core(), it appears that if the logging level is set
>> to disallow a particular message from being logged, that
>> log_error_core() returns before doing any argument processing.  So the
>> overhead would only consist of a few function calls, and my sense would
>> be that saving that wouldn't make a big difference.
> You describe the internal arg processing.  Keep in mind that fn args aren't
> conditionally processed, they must be created before being passed to the
> function.  If we can dodge that with a module query 'is mod_foo at loglevel
> debug here?' then we can optimize this considerably.
> A minimum vector is per-vhost-per-module, but per-dir-per-module would be
> even better :)  At that granularity, and adding per-mod forensics, the user
> can be grabbing lots of detail on one specific module in the single context
> that is causing that module to misbehave.

Yes, see the implementation of the Noit Logger which I linked to, it
uses a Macro to check if a logger is enabled, so you don't have the
function arg prep/frame overhead if a logger isn't enabled.

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