Re: Not able to make full use of CPUs for processing speed

On 9/16/21 10:08, Bill Deegan wrote:
> you can also use the --taskmastertrace=FILE scons option and look at the 
> output file, that may give you hints why you're not getting the 
> parallelism you suspect, though that's a deeper dive.


I guess a question to answer is if there's enough parallelism available 
in your setup that a larger jobs pool helps.  If there rarely are 
situations when more than five builds are ready to run at once, 
increasing the jobs pool way beyond five is unlikely to help much.  Not 
sure there's a really good way to get SCons to tell you that... a lot of 
the information is in the taskmaster trace, sure, but my experience is 
using it is kind of like trying to drink from a firehose most times.

There should probably be some kind of sampling profile setup to help 
figure out if things aren't being kept busy just because there's not 
unblocked work available, or if SCons is blowing too much time 
calculating things... it's my impression (don't shoot me, Bill!) that 
the performance characterizations that were made of SCons and its 
taskmaster/jobs setup were done on computing technologies several 
generations removed from today's and could stand a revisit.