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From: Preston A. Elder (prez_at_[hidden])
Date: 2007-11-01 07:56:18

On Thu, 01 Nov 2007 11:52:40 +0200, John Torjo wrote:

>> But the most important thing here is that it is flexible (you can
>> create your own appenders, formatters, etc and register them with the
>> system and they will act as if they were built in) and FAST. Plus it
>> is configurable
> It certainly is extensible - quite a lot ;)

I see that :)

>> Anyway, my code might be worth a look - but coming back to my initial
>> question have you done speed benchmarks? Or thought about not using
>> streams?
> I haven't done speed benchmarks yet, but as a side-note, I want to
> create a class that will benchmark how long the app spends doing
> logging. Also, if you turn "compile fast" mode off, you'll avoid one
> virtual call.
> About using streams - this is really your call. It's all about gathering
> your data:
> So gathering can happen using streams, or you can choose your own Log
> Syntax, avoiding streams.
OK, but the default file appender is not using iostreams?

> Note that logging can also become way faster if you do it on a dedicated
> thread (on_dedicated_thread.hpp class). I haven't yet tested this, but
> it's gonna be way faster than doing logging on the thread the message is
> logged. Basically, the only thing that happens in the current thread is
> gathering the message. Writing it (formatting it and then writing it to
> the destination(s)) will happen on the other thread.
> Thus, any destination you might have - can automatically become
> asynchronous as well ;) )
Yah, log4cxx and my logger also support async logging. But this is not
possible where I work (large financial). If use async logging, you have
a queue between your app thread and the logging thread. If your app
crashes, anything in that queue is lost. This is hell on wheels for
debugging. Plus some important information is lost ("Oops! We don't
know which of the $30 million in trades were sent to the market and which
weren't!"). So while I know Async logging is faster, it is not practical
in any important application.

> (note : your appenders = my destinations)
> I'd be curious to see how my lib benchmarks against what solution your
> company took ;)
I will see if I can grab your logger and benchmark it against mine -
first using generic formatters, then using custom formatters (which
increase efficiency dramatically).

PreZ :)

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