Hook up the link pool in the GN build.

Hook up the link pool in the GN build.

This uses the code from GYP to compute the maximum number of concurrent links
to use in the link pool, and sets this value in the toolchains.

Committed: https://crrev.com/937a6d51df85cd7e338b952aeacb03bf7e5726c2
Cr-Commit-Position: refs/heads/master@{#294007}

[brettw, 2014-09-09 17:15:57]

brettw@chromium.org changed reviewers:
+ scottmg@chromium.org

[scottmg, 2014-09-09 18:04:48]

Is this to fix something? It mostly sucked in gyp, so I'm not sure it's a win to
port it over.

[scottmg, 2014-09-09 19:37:51]

On 2014/09/09 18:04:48, scottmg wrote:
> Is this to fix something? It mostly sucked in gyp, so I'm not sure it's a win
to
> port it over.

ok, per discussion lgtm.

i don't think it's useful on dev machines because e.g. it'll only be capping at
16 concurrent links on a z620 with 64G of ram, but maybe the legacy gyp_*
behaviour is useful on bots.

[brettw, 2014-09-09 19:39:04]

The CQ bit was checked by brettw@chromium.org

[commit-bot: I haz the power, 2014-09-09 19:58:28]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/brettw@chromium.org/548633004/1

[commit-bot: I haz the power, 2014-09-09 20:58:08]

Committed patchset #1 (id:1) as f8f8574fbe6ac7691a870196b3584bb5cb9bcdd0

[Nico, 2014-09-09 21:04:25]

On 2014/09/09 19:37:51, scottmg wrote:
> On 2014/09/09 18:04:48, scottmg wrote:
> > Is this to fix something? It mostly sucked in gyp, so I'm not sure it's a
win
> to
> > port it over.
> 
> ok, per discussion lgtm

(can you summarize the discussion here, for future archeology?)

[brettw, 2014-09-09 21:11:27]

We added this originally in GYP/Ninja because it would sometimes lock up your
machine toward the end of a build doing more links in parallel than the machine
could handle. This might not be a problem on current developer desktops, but on
some bots it might be good, and GYP compat here seems like a good idea.

[commit-bot: I haz the power, 2014-09-10 03:55:34]

Patchset 1 (id:??) landed as
https://crrev.com/937a6d51df85cd7e338b952aeacb03bf7e5726c2
Cr-Commit-Position: refs/heads/master@{#294007}