Re: [boost] [xpressive] Performance Tuning?

Subject: Re: [boost] [xpressive] Performance Tuning?
From: OvermindDL1 (overminddl1_at_[hidden])
Date: 2009-07-28 10:54:15

On Tue, Jul 28, 2009 at 8:49 AM, Edward Grace<ej.grace_at_[hidden]> wrote:
>>> That does not make use of boost::bind - but tries to avoid the optimizer
>>> getting rid of void(void) functions by using globals.
>>
>> I have no clue why I am still awake, brain is already shut down, code
>> is a blurry blob to me right now, but I still compiled and ran your
>> latest file.  :)
>
> Thanks.
>
>> The results:
>>
>> initializing input strings...
>> Calibrating overhead......done
>> Timer overhead (t_c) ~= : 12
>> Jitter               ~= : 8.43769e-015
>> qi_parse vs atoi    : 1381.05 1385.57 1389.6% faster.
>> qi_parse vs strtol  : 1365.82 1389.6 1597.94% faster.
>> strtol vs atoi      : 1.03202 1.04052 10.6428% faster.
>> qi_parse vs qi_parse : 0 0 0% faster.
>
> Hmmm....  So you observe the same as me.  Spirit2 ~1000% faster than the
> basic libraries as opposed to 25% faster from the previous tests.
>
> "Curiouser and curiouser" said Alice.

Heh, when my brain is functional again, if I remember (or if I am
reminded by this email) I will run it through a profiler and see what
is going on as well as looking at the disassembly to see what kind of
code it all creates.

It is definitely odd though, if Spirit2.1 really is faster, then you
would think the compiler library programmers would do a better job
then what they are currently doing.  I am really curious to find out
what is going on, hopefully delving into assembly later will shed some
light.