Re: building LLVM threads gets killed

On 22 Aug 2018, at 04:01, Mark Millard <marklmi_at_yahoo.com> wrote:
> 
> Brooks Davis brooks at freebsd.org wrote on
> Tue Aug 21 20:29:45 UTC 2018 :
> 
>> On Mon, Aug 20, 2018 at 07:33:32PM +0200, Dimitry Andric wrote:
>>> . . .
>>> 
>>> I have attached a patch for most of the llvm ports, which sets the
>>> LLVM_PARALLEL_LINK_JOBS CMake flag during the configure phase.
>> 
>> Committed in r477756.
>> 
> 
> lld itself has --threads (default) and --no-threads
> (non-default, single threaded link). (Mark Johnston
> recently made me aware of this.) In my quick experiment
> in just one context, --threads used 5 or so threads
> in the lld process. (Likely helps with speed when
> the hardware threads are simply available without
> conflicts.)
> 
> Does LLVM_PARALLEL_LINK_JOBS contribute to which of
> these is in use?

No, it just controls how many link processes ninja starts in parallel.
If those link processes use threads, like lld does by default, it is
outside the control of ninja.

Note that lld uses threads to speed up linking, but it might use more
memory, so you could turn it off if you are memory constrained.

-Dimitry