Re: [jamboost] Re: [Boost-build] CVS: boost/tools/build/v1 allyourbase.jam,1.56,1.57 boost-base.jam,1.143,1.144

From: Rene Rivera (grafik.list_at_[hidden])
Date: 2004-11-17 11:56:04

Vladimir Prus wrote:
> On Wednesday 17 November 2004 11:30, Rene Rivera wrote:
> 
> 
>>Modified Files:
>> allyourbase.jam boost-base.jam
>>Log Message:
>>Fix extra updates on targets when a header has the same name as a directory
>>which is in the headers search path.
>>
>>+ if ! [ GLOB "$(bound-path)" : * ]
>>+ {
>>+ header-locate = $(bound-path) ;
>>+ }
> 
> Rene, did you do any performance testing of this patch? This seems to me a 
> pretty easy way to kill performance. FWIW, I've spend some time removing any 
> loops from V2 header scanning because of performance reasons.

It will definitely make things slower... And there are ways to make it 
faster. But this is BBv1 so the lifetime is limited, it can be improved 
with some caching if needed. I expect that we can come up with a much 
better fix for BBv2. Most likely adding some Jam native rule to handle this.

While working on this I noticed a rather slow aspect of the way binding 
works in Jam. If a binding does not already exist it will do directory 
scans every time to search for a binding. That should be a candidate for 
caching, no point in scanning the same directories over and over for 
each target.

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