On 2023.05.06 07:50, Peter Humphrey wrote:
Hello list,
I still don't know how this works. I ran a test over the last two
days, and
the result does not accord with 'man make.conf' nor 'man 1 make'.
First, 'man make.conf' does not state that --load-average, if set,
will
override --jobs, as it clearly does.
Second, the two pages contribute actively to the confusion between
the emerge
jobs submitted in parallel by portage and the concurrent tasks that
may be
launched by each of those.
The test:
I ran 'emerge -e @world' with EMERGE_DEFAULT_OPTS="--jobs=10 --load-
average=40 ...". It took 350m46s.
Then I ran the same -e with --load-average=40, but no --jobs and no
-j. That
took 351m21s - 35 seconds longer! What's worse, the load average was
controlled at about 72, not 40. I watched it for some time, and even
though
all three load averages were at 72-75, portage kept on starting more
packages.
As far as I could see, swap was not touched.
The machine has 24 threads and 64GB RAM (not to mention plenty of
swap), so
how was the 72 figure arrived at?
I still don't know how to control the number of simultaneous
compilations,
short of limiting them to one.
--
Regards,
Peter.
Minor point - are you sure ccache isn't affecting your results?
I hope I'm not preaching to the choir, and I have NOT reread the
various man pages, but the different options you mention (and some you
don't) apply to different parts of the process. Some tell emerge
whether or not to start working on another package, but once it starts
the process, it has no control over how busy the machine can get. Then
there are those that get passed to make. I wouldn't think so, but are
you possibly confusing the two? Lastly, I don't see that those that
apply to make would have any effect on packages that use ninja instead,
so that might also contribute to the issue..
Separate question, only vaguely related: is there any easy way to tell
what build tools (ninja vs make, gcc vs clang vs ?) were used for an
installed package without actually looking into the ebuild? It's
probably not relevant to your question about controlling the load, but
I used to rebuild everything after installing a new version of gcc, and
have since realized there are many packages that make no use of gcc, so
the rebuild serves no point, and I miss rebuilding packages that use
clang after an upgrade of it and related tools.
Jack
