Re: Do I need to build B2/bjam with options to run with all cores?

On Mon, Jul 8, 2019 at 12:27 PM Paul A Bristow via Boost-build <
[email protected]> wrote:

> The Quickbook documentation build  of Boost.Math is on my critical path
> of the ‘edit-compile-run-crash’ cycle 😉
>
> When the docs build, it only ever uses one core, leaving 15 of my shiny new
> cores idle ☹
>
> I have tried adding -j15 (even though I understand that this is now the
> default).
>
Not even that is required now, since it's suppose to use all the cores by
default. But doesn't hurt to be explicit.

> Do I need to compile b2 in some multiprocessor way to get all cores
> working and hopeful cut the build time?
>
No.

> (In contrast, if I build all the math examples or tests etc, I get all
> the cores working at 100%).
>
> Or am I expecting the impossible?
>
I would guess there's something about the documentation build that isn't
parallelizable. And thinking about it, it makes some sense. Building a
single library documentation is a linear sequence of steps: source qbk =>
boostbook => xslt transform to docbook => xslt transform to html. Do you
have some other dependency chain arrangement that would theoretically allow
parallel processing? Or are you talking about some other intrinsic
multi-core capability of an individual transform step?

-- 
-- Rene Rivera
-- Grafik - Don't Assume Anything
-- Robot Dreams - http://robot-dreams.net

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