[Intel-gfx] [IGT PATCH 2/2] aux: Use IGT version of system() call to run rtcwake

[Chris Wilson]

Quoting Imre Deak (2017-10-12 14:22:07)
> The clone() system call has difficulty to make progress if interrupted
> frequently by the signal helper process. At least on an APL, like in the
> Bugzilla ticket below, this can introduce minutes of overhead to a
> single system() call (leading to a global CI timeout). To get rid of the
> overhead suspend the signal helper process for the duration of the
> system() call, which is provided already by igt_system().

The alternative is to pull small binaries into ourselves, e.g.
converting system("modprobe") to libkmod calls fixed a bunch of similar
issues (under kasan they were slow even without interruptions!).
We could absorb rtcwake in a couple of hundred lines, if the system() is
slow enough to be interrupted, it's slow. ;)

> 
> Cc: Chris Wilson <chris at chris-wilson.co.uk>
> Cc: Daniel Vetter <daniel.vetter at intel.com>
> Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=103160
> Signed-off-by: Imre Deak <imre.deak at intel.com>
Reviewed-by: Chris Wilson <chris at chris-wilson.co.uk>
-Chris