Re: [boost] [xpressive] Performance Tuning?

Subject: Re: [boost] [xpressive] Performance Tuning?
From: Edward Grace (ej.grace_at_[hidden])
Date: 2009-07-20 15:40:08

>>     chrono_start = chrono();
>>     while ( double( chrono_wall() - chrono_wall_start ) <
>> chrono_wall_scale*4.0);
>>     chrono_end = chrono();
>>
>> I'm now doubly confused as it appears to be complaining about the  
>> return
>> type of std::clock, (the default wall-clock timer).  Maybe I can  
>> get my
>> hands on a windows machine and compiler tomorrow....
>
> Edward, just a compliment (for now): what you are doing is cool!
> I'm starting to be an eager supporter.

Always good to hear.... ;-)

After a mammoth effort and much code rejigging I've got it to not  
only compile, but work on Windows with MSVC8!  In fairness to the MS  
compiler it did spot some subtle run-time errors that I was getting  
away with just fine with g++.   I've had to rip out parts that used  
my home brew striding_iterator since there's no way to avoid  
dereferencing one past the end of the end.

Similarly I've had to give up on keeping all the time deltas as  
integer types in order to cope with the Windows .QuadPart approach.   
If you refer back to the discussion I was having with OverminD1  
(thanks a lot for your efforts) you'll see it was causing some grief  
when trying to compile on Windows.   As a consequence the timer  
appears to be less sensitive, so may not pick out differences < 0.5%,  
but frankly who cares? ;-)

Anyhow, enough rambling:

   http://tinyurl.com/km9xlh

The new timing code (with a better PDF containing docs) is:

   ejg-timer-0.0.3.tar.gz

Those of you watching in black and white need to set up MSVC and  
compile example_timer.cpp.  Everyone watching in colour need only do  
the usual:

   ./configure; make; make install

voodo...

The uint_parser example that utilises the above is:

   ejg_uint_parser_0_0_3.cpp

I wait with baited breath.

-ed

------------------------------------------------
"No more boom and bust." -- Dr. J. G. Brown, 1997