[Scons-dev] scons-2.5.0 performance issue?

Thomas Berg merlin66b at gmail.com
Tue Apr 12 06:57:44 EDT 2016


William,

I ran scons --tree=prune on a small subset of our build, and the text
output goes up from 7.5MB to 35MB for that subset. I guess that means
the dependency graph is four times bigger now.

Cheers,
Thomas

On Tue, Apr 12, 2016 at 12:43 PM, Thomas Berg <merlin66b at gmail.com> wrote:
> Bill,
>
> Here is the output of --debug=objects:
> https://dl.dropboxusercontent.com/u/40097540/misc/scons/scons_objects_2_4_1.txt
> https://dl.dropboxusercontent.com/u/40097540/misc/scons/scons_objects_2_5_0.txt
>
> Both are around 22MB, so here's a 3MB zip containing the two files:
> https://dl.dropboxusercontent.com/u/40097540/misc/scons/scons_objects_output.zip
>
> The 2.5.0 output is around 2000 lines longer than the 2.4.1 output,
> both are around 430 000 lines.
>
> As a test, is it possible to disable the cross language scanner
> somehow, either by passing something to the environment or patching
> the scons code?
>
> Dirk: thanks for the link. I have tested some but not all the tricks
> used there, and I will definitely look closer at it after we
> (hopefully) get to the bottom of this.
>
> I would at least like to understand what's going on in our case, so
> thanks for all the help. Could it be that just adding a small number
> of dependencies in the wrong place can, due to recursive effects,
> cause such a significant increase in the processing time?
>
> Thanks,
> Thomas
>
>
>
>
> On Mon, Apr 11, 2016 at 6:02 PM, Dirk Bächle <tshortik at gmx.de> wrote:
>> Hi Thomas,
>>
>> On 11.04.2016 16:59, Thomas Berg wrote:
>>>
>>> Bill, below is the output of --debug=count, it is identical with
>>> scons-2.4.1 and scons-2.5.0.
>>>
>>> Since my case was about the no-op build (nothing is built), less
>>> parallelization should not be an issue. ...
>>
>>
>> if you haven't already done so, you might want to try out my "fastcpp"
>> extension at:
>>
>>   https://bitbucket.org/dirkbaechle/scons_fastcpp
>>
>> . It may give you some speedup, but please regard its disclaimer.
>>
>> Best regards,
>>
>> Dirk
>>
>>
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