Re: [Boost-users] [spirit] benchmarks/qi benchmarks valid?

Subject: Re: [Boost-users] [spirit] benchmarks/qi benchmarks valid?
From: Joel de Guzman (joel_at_[hidden])
Date: 2009-09-14 11:21:10

Steven Watanabe wrote:
> AMDG
> 
> Daniel Mierswa wrote:
>> I was merely wondering if what I'm doing is right or if I fail at 
>> basic benchmarking:
>>
>> impulze_at_istari ~/dev/repositories/boost.svn/libs/spirit/benchmarks/qi 
>> $ g++ -O3 int_parser.cpp -I../../../../ -lrt && ./a.out
>> <snip>
>> atoi_test:            5.0041852930 [s] {checksum: 13f6bf40}
>> strtol_test:          5.4193627260 [s] {checksum: 13f6bf40}
>> spirit_int_test:      2.2137115780 [s] {checksum: 13f6bf40}
>>
>>
>> impulze_at_istari ~/dev/repositories/boost.svn/libs/spirit/benchmarks/qi 
>> $ g++ -O0 int_parser.cpp -I../../../../ -lrt && ./a.out
>> <snip>
>> atoi_test:            0.5902040060 [s] {checksum: e9ed193a}
>> strtol_test:          0.6001010490 [s] {checksum: e9ed193a}
>> spirit_int_test:      3.6562933090 [s] {checksum: e9ed193a}
> 
> -O0 means no optimization.
> 
>> According to this, the optimized binary is 10 times slower wrt to the 
>> atoi/strtol implementation. I find that somehow quite hard to believe, 
>> is my toolchain broken, the testsuite or is it really true? The level 
>> of optimization doesn't matter btw, I get similar results with -O[,1,2]

This has been discussed in the Spirit list. Seems that the test
is skewed bigtime with no optimization. The benchmarks were
designed with full optimization, of course.

Regards,
-- 
Joel de Guzman
http://www.boostpro.com
http://spirit.sf.net
http://doiop.com/jdg_facebook