On 11/23/2011 7:32 PM, Joel de Guzman wrote:
On 11/24/2011 7:30 AM, Hartmut Kaiser wrote:
Something is definitely fishy with your Spirit numbers.
Yes, there's something wrong with the numbers alright. We have extensive int and real number tests in Spirit. I did a run and here's what I got:
Check it out. It's in:
boost/libs/spirit/optimization/
It doesn't include lexical_cast or iterator_range which is the topic here. My Spirit discrepancy is interesting (and I'd like to resolve it) but not on topic. MSVC 9 SP1 ---------- Compile options (minus some warning flags): /Ot /GL /D "WIN32" /D "NDEBUG" /D "_UNICODE" /D "UNICODE" /FD /EHsc /MD /Fo"Release\\" /Fd"Release\vc90.pdb" /c /TP Link options (minus some manifest stuff): /OPT:REF /OPT:ICF /LTCG /DYNAMICBASE /NXCOMPAT /MACHINE:X86 ---------- 1000000 iterations of "123": atoi: 0.0391888 seconds strtol: 0.038651 seconds Spirit: 0.273361 seconds lexical_cast(string): 0.248789 seconds lexical_cast(iterator_range): 2.24887 seconds lexical_cast(iterator_range->string): 0.340937 seconds 1000000 iterations of "123567890": atoi: 0.0631489 seconds strtol: 0.0616906 seconds Spirit: 0.52429 seconds lexical_cast(string): 0.311549 seconds lexical_cast(iterator_range): 3.60336 seconds lexical_cast(iterator_range->string): 0.411227 seconds 1000000 iterations of "1.23456": atof: 0.489091 seconds strtod: 0.50077 seconds Spirit: 0.578644 seconds lexical_cast(string): 2.88651 seconds lexical_cast(iterator_range): 5.84474 seconds lexical_cast(iterator_range->string): 3.00146 seconds 1000000 iterations of "1.23456789e42": atof: 0.689908 seconds strtod: 0.701619 seconds Spirit: 0.871071 seconds lexical_cast(string): 3.27655 seconds lexical_cast(iterator_range): 7.47095 seconds lexical_cast(iterator_range->string): 3.41462 seconds MSVC 10 ------- Compile options (minus some warning flags): /Zi /O2 /Ot /Oy- /GL /D "WIN32" /D "NDEBUG" /D "_UNICODE" /D "UNICODE" /Gm- /EHsc /MD /GS /fp:precise /Zc:wchar_t /Zc:forScope /Fp"Release\test.pch" /Fa"Release\" /Fo"Release\" /Fd"Release\vc100.pdb" /Gd /analyze- Link options (minus some manifest stuff): /PDB:"D:\test\test\Release\test.pdb" /SUBSYSTEM:CONSOLE /OPT:REF /OPT:ICF /PGD:"D:\test\test\Release\test.pgd" /LTCG /TLBID:1 /DYNAMICBASE /NXCOMPAT /MACHINE:X86 ------- 1000000 iterations of "123": atoi: 0.0428806 seconds strtol: 0.0381644 seconds Spirit: 0.0155017 seconds lexical_cast(string): 0.176925 seconds lexical_cast(iterator_range): 1.75922 seconds lexical_cast(iterator_range->string): 0.193789 seconds 1000000 iterations of "123567890": atoi: 0.0587083 seconds strtol: 0.0606732 seconds Spirit: 0.0342255 seconds lexical_cast(string): 0.201997 seconds lexical_cast(iterator_range): 2.49349 seconds lexical_cast(iterator_range->string): 0.210316 seconds 1000000 iterations of "1.23456": atof: 0.450875 seconds strtod: 0.448144 seconds Spirit: 0.0557749 seconds lexical_cast(string): 2.53753 seconds lexical_cast(iterator_range): 4.62941 seconds lexical_cast(iterator_range->string): 2.55487 seconds 1000000 iterations of "1.23456789e42": atof: 0.656821 seconds strtod: 0.657229 seconds Spirit: 0.0721354 seconds lexical_cast(string): 2.87113 seconds lexical_cast(iterator_range): 5.72209 seconds lexical_cast(iterator_range->string): 2.91933 seconds The Spirit issue seems to be between MSVC 9 and 10. Still off topic, but is anybody able to get better Spirit results with MSVC 9? Finally, I got lexical_cast down to its best performance with BOOST_LEXICAL_CAST_ASSUME_C_LOCALE (again using MSVC 10). There is some kind of optimization going on with the iterator_range->string branch, so let's ignore that. I added a sscanf line for better comparison with http://www.boost.org/doc/libs/1_48_0/doc/html/boost_lexical_cast/performance... : 1000000 iterations of "123": atoi: 0.0395041 seconds strtol: 0.037376 seconds sscanf: 0.141029 seconds lexical_cast(string): 0.0169919 seconds lexical_cast(iterator_range): 1.54364 seconds 1000000 iterations of "123567890": atoi: 0.0575238 seconds strtol: 0.0577509 seconds sscanf: 0.194656 seconds lexical_cast(string): 0.0428486 seconds lexical_cast(iterator_range): 2.23957 seconds 1000000 iterations of "1.23456": atof: 0.437103 seconds strtod: 0.45665 seconds sscanf: 0.590672 seconds Spirit: 0.0519114 seconds lexical_cast(iterator_range): 4.63105 seconds 1000000 iterations of "1.23456789e42": atof: 0.63978 seconds strtod: 0.673893 seconds sscanf: 0.888611 seconds lexical_cast(string): 2.88724 seconds lexical_cast(iterator_range): 5.65133 seconds Still we see that lexical_cast is quite slow for string->float (at least on MSVC 10) which doesn't match the GCC results on the performance.html page and it's abysmal for converting iterator_ranges. In case someone else wants to try, the latest code I'm using to test: http://codepad.org/P6Os5MKf I'm hoping Antony Polukhin will chime in and say how hard it would be to add iterator_range specializations and redirect the existing string->T specializations to forward to the iterator_range ones. I don't understand the TMP in the new lexical_cast. Also, [Antony] please add something like: "Tests were compiled with BOOST_LEXICAL_CAST_ASSUME_C_LOCALE defined for optimum performance." to the test description on the performance.html page? Thanks, -Matt