[Scons-users] Clone effectiveness

[Mats Wichmann]

On 09/13/2018 12:52 PM, Damien Hocking wrote:
> We do this too.  Most dlls and sos have a cloned environment.

As I said earlier, we clone lots (>90% of our sconscripts contain a
Clone() call), but the actual build time dwarfs the "process the
SConscripts" phase (*) so I don't worry much about it. We're not getting
killed on memory; I can build easily enough in a 2gb Vagrant-provisioned
(Linux) image. So while I'd like to *know* the numbers, it's mostly
curiosity.

Maybe we can resurrect some of the benchmarking/timing code that exists
in the codebase now to get more info?

* - recent build timings:
Total build time: 360.533189 seconds  (using scons -j4)
Total SConscript file execution time: 14.785102 seconds

15 seconds is slow, but if I sped up the sconscript time by 50%, I'd
still make no more than a 2% impact on the overall time.

>> On Sep 13, 2018, at 12:27 PM, Pierre-Luc Boily <pierreluc.boily at gmail.com> wrote:
>>
>> Hello!
>>
>> Just read on the forum :
>>
>> /Here's the caveat.
>> Don't make a gazillion Clone's they're not lightweight.
>> If you make 100, it won't kill you, if you make 1000's you may start seeing
>> memory and speed impacted./
>>
>> Our project branch contains 800 sconscript files.  From those 800, 300 are
>> for windows compilation, 500 are for unix compilation.
>>
>> We systematically create a clone of the environment at the beginning of
>> *each *sconscript.  So, if I understand well, it might not be the best
>> approach.  It would be better to do a Clone only when it is needed? 
>> Reducing the number of clone could potentially speed up the creating of the
>> tree?
>>
>> Thx
>>
>>
>>
>> --
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