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Subject: Re: [Boost-build] It's time for my per release beg for patch on ticket #2552 (Extending bjam to accept parameters 10-19)
From: Jon Biggar (jon_at_[hidden])
Date: 2009-11-03 23:24:16

Vladimir Prus wrote:
>>>> 1.41 is coming soon. Can the patch in this ticket please be integrated
>>>> this time? It's been pending since 1.36.
>>> What is the change in performance and memory consumption of bjam with
>>> this patch, when building Boost C++ Libraries?
>> It increases the storage requirements for bjam rule parameters from
>> 9*sizeof(pointer) to 19*sizeof(pointer) for the memory allocation
>> associated with each bjam rule invocation stack frame.
>> It adds slight overhead when parsing rule text to find parameters $(10)
>> through $(19).
>> I expect the effects of either to be quite small.
> Given that you surely have both the patched version and the original version,
> can you try? The gut feeling is that the change should not be huge, but gut
> feelings are often wrong.

Unfortunately my main home linux machine went down, so I had to do this
on a VM which is somewhat memory constrained and accesses its storage
over NFS. I ran 'time bjam stage' on the entire 1.40.0 distro and got
these results:

original bjam: 166.328u 167.922s 18:33.62 30.0%
bjam with patch: 144.215u 157.788s 19:24.57 25.9%
second run: 158.794u 171.369s 18:32.89 29.6%

So with my setup, I can't detect any significant time difference.

Jon Biggar

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