Re: Add a cooperative FS lock to lilypond-book. (issue 555360043 by address@hidden)

[dak]

On 2020/02/23 16:23:34, hanwenn wrote:
> On 2020/02/23 16:05:08, dak wrote:
> > On 2020/02/23 15:54:54, hanwenn wrote:
> > > I think this is worth it because it simplifies the build system,
and puts
> the
> > > locking in the place where we actually access the resource.
> > 
> > Is there any indication that letting Make run multiple instances of
> > lilypond-book with every instance except one at a time locking up is
going to
> be
> > a net win for performance?
> 
> input/regression/lilypond-book:
> 
> rm -rf out-tst; time make out=tst local-test -j4 CPU_COUNT=4
> 
> 
> before
> real  1m16.588s
> 
> after
> real  0m25.224s

So the idea is not as much to run parallel instances of lilypond-book
but rather let lilypond-book itself do the serialization.

The net result will be that Make counts lilypond-book's use of 4 CPUs as
just a single CPU, so unless the parallel makes run into a locking
instance of lilypond-book, this will now result in a maximum of 7 jobs
in parallel, right?

https://codereview.appspot.com/555360043/