Re: [boost] [xpressive] Performance Tuning?

Subject: Re: [boost] [xpressive] Performance Tuning?
From: Edward Grace (ej.grace_at_[hidden])
Date: 2009-07-29 06:20:44

>> Proceeding to timing tests.Calibrating overhead......done
>> Timer overhead (t_c) ~= : 117.426
>> Jitter               ~= : 25.9133
>> qi_parse vs atoi    : 86.0764 86.3074 86.4471% faster.
>> qi_parse vs strtol  : 71.9253 72.1881 72.5288% faster.
>> strtol vs atoi      : 8.0502 8.26097 8.47215% faster.
>> qi_parse vs qi_parse : -0.0274542 0.0393936 0.231944% faster.
>>
>>
>> All done!
>> ====================
>>
>>
>> On my platform this is entirely consistent with the simple one-liner
>> modification you mentioned to the previous code.
>>
>> Take home message - yes Spirit really *is* faster.
>
> Enter buffer size: 10000
> initializing input strings...
>
>
>
> Checking that the parsers are functioning  correctly...
> atoi is behaving itself!
> strtol is behaving itself!
> qi is behaving itself!
>
> Proceeding to timing tests.Calibrating overhead......done
> Timer overhead (t_c) ~= : 12
> Jitter               ~= : 8.43769e-015
> qi_parse vs atoi     : 160.834 187.892 197.781% faster.
> qi_parse vs strtol  : 152.088 173.709 197.184% faster.
> strtol vs atoi       : 5.34019 7.29527 9.82952% faster.
> qi_parse vs qi_parse : -3.12862 -0.194198 1.53912% faster.
>
> All done!
>

[fixed with font required]

Interesting.  So, there is no difference between the speedup of  
strtol and atoi between your platform and mine (their confidence  
intervals overlap).

strtol vs atoi

OvermindDL1:   [5.3 ---------x-------- 9.8] %

          Ed:           [8.1 --x- 8.5] %

on the other hand qi_parse is significantly faster under Windows on  
your architecture compared to atoi than OS X.

qi_parse vs atoi

OvermindDL1:                                                    
[160.8  ---------x-- 197.8] %

          Ed:   [86.0 -----x----- 86.4] %

Likewise in both cases the timing of qi_parse against itself shows no  
difference since the confidence interval includes zero.

qi_parse vs qi_parse

OvermindDL1: [-3.13 ----------- 0 ----------- +1.54] %

          Ed:          [-0.03 -- 0 -- +0.23] %

> MSVC definitely compiles templates code better then GCC

More warnings?

> it seems (you
> said you were using GCC yes?).

Yes.... I wonder why am I starting to feel sheepish about that...

-ed