Re: [Boost-build] Parallel vs serial gcc linker invocation

Subject: Re: [Boost-build] Parallel vs serial gcc linker invocation
From: Jürgen Hunold (jhunold_at_[hidden])
Date: 2015-06-01 01:20:45

Hi Jim, 

Am Sonntag, 31. Mai 2015, 21:41:41 schrieb Jim Thoenen:
> As an experiment, in gcc.jam, I commented out the link rules'
> "JAM_SEMAPHORE on $(targets)" lines to allow independent links to run in
> parallel, and the speedup was dramatic.

Yes, that is to be expected. At least until the link jobs eat up the available 
memory, which is why the semaphore exists.

> It would be very nice if there was a feature or some mechanism to control
> whether or not independent linker invocations are allowed to run in
> parallel.  Thoughts?

IMHO, we need an a separate option to control the number of allowed link jobs. 
It must be independent of the -j option controlling the number of compile 
jobs. The rationale behind this is that some people (read: myself) use 
distributed compiles like icecc with -j96 and don't want that many linker 
started locally, especially when doing things like static linking or huge 
monolithic shared libraries.

My 0.02 €

Yours,

Jürgen
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