Re: [bug #40225] Deterministic output ordering

[Frank Heckenbach]

Tim Murphy wrote:

> One problem with reordering is how do you do it without actually
> affecting the way you schedule jobs?

Dunno, maybe just like I described it in
http://lists.gnu.org/archive/html/bug-make/2013-10/msg00065.html

> [...]
> 
> So, you might say, it's not random because there are 64 CPUs and jobs
> are allocated round-robin so there's some window of something around
> 64 (perhaps more) bits of output that one would have to keep given
> that the scheduler is still iterating over jobs in the same order and
> given that the execution time of each job doesn't change.
>
> But now what if make decides to execute jobs in a different order from
> one build to the next for some very good reason?  What if you run the
> build on a machine with a much faster disc than CPU and jobs stop
> completing in the same way.  That would make it a lot less scalable to
> implement.

No, I might not say what you think I'd say. What I might say is what
I actually did say (see above). In particular:

- output-sync *already* does redirect every command's output to a
  separate (currently temporary) file. No need to buffer it in
  memory.

- My suggestion relies on the order the jobs are *started* (which,
  as I said, ought to be deterministic and the same as with "-j0",
  though Paul should know this better than me). The order in which
  they finish can, of course, depend on the number of CPUs, disk
  speed and phase of the moon, but it wouldn't matter.

Apparently you don't like my proposal. Fine, feel free to implement
something else. But please don't make up problems that don't exist.