Re: [boost] Proposed templated integer_sort

From: David Abrahams (dave_at_[hidden])
Date: 2008-07-03 17:02:23

Steven Ross wrote:
> On Thu, Jul 3, 2008 at 9:36 AM, Phil Endecott <
> spam_from_boost_dev_at_[hidden]> wrote:
> 
>> I'll have a look at that.  What do we think about "magic tuning parameters"
>> in algorithms?  My feeling is that things dependent on e.g. cache sizes (or
>> number of processors etc) really need to be determined at run time to be
>> useful to most people.
>>
> 
> The values I picked are pretty good across most systems.  If there is a
> standard, quick way to find the size of the processor cache, then I could
> consider using it.  By far the most important parameter MAX_SPLITS is
> dependent on the page size, and 9 corresponds to the number of bins that
> take up 4096 bytes on a 32-bit system, which is a common page size.
> introsort looks like it has a tuning parameter of 16 in SGI's
> implementation.

It would be really good to get an ATLAS-like tuning framework into Boost
so people could configure these things properly at installation time.

-- 
Dave Abrahams
BoostPro Computing
http://www.boostpro.com