Re: RFC: subcommand to pause/resume builds

[Mark H Weaver <mhw@netris.org>]

Hi Ludovic,

Ludovic Courtès <ludo@gnu.org> writes:

> Last, you’d need to send SIGTSTP to the whole process group of the
> build, like so (I think, haven’t tried):
>
>   sudo kill -TSTP -123
>
> where 123 is the “SessionPID” shown by ‘guix processes’.  However, doing
> so may affect build results: processes in the build environment might
> handle SIGTSTP specially, which can have side effects.  It’s an
> observable action.

What's the rationale for using SIGTSTP instead of SIGSTOP here?

FWIW, on a few occasions I've paused builds by sending SIGSTOP to the
relevant process group, and later SIGCONT, and it has worked for me.  As
I recall, I've done this while building rust, webkitgtk, and icecat.

However, I suspect that if I paused a build while running tests, the
test suite might ultimately fail due to a "timeout".

> Conclusion: I don’t think we can implement this reliably.

Agreed.

     Thanks,
       Mark