Re: [gentoo-user] Controlling emerges

[Alan McKinnon <alan.mckinnon@gmail.com>]

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On Mon, Sep 18, 2023 at 6:03 PM Peter Humphrey <peter@prh.myzen.co.uk>
wrote:

> On Monday, 18 September 2023 14:48:46 BST Alan McKinnon wrote:
> > On Mon, Sep 18, 2023 at 3:44 PM Peter Humphrey <peter@prh.myzen.co.uk>
> >
> > wrote:
> > > It may be less complex than you think, Jack. I envisage a package being
> > > marked
> > > as solitary, and when portage reaches that package, it waits until all
> > > current
> > > jobs have finished, then it starts the solitary package with the
> > > environment
> > > specified for it, and it doesn't start the next one until that one has
> > > finished.
> > > The dependency calculation shouldn't need to be changed.
> > >
> > > It seems simple the way I see it.
> >
> > How does that improve emerge performance overall?
>
> By allocating all the system resources to huge packages while not flooding
> the
> system with lesser ones. For example, I can set -j20 for webkit-gtk today
> without overflowing the 64GB RAM, and still have 4 CPU threads available
> to
> other tasks. The change I've proposed should make the whole operation more
> efficient overall and take less time.
>
> As things stand today, I have to make do with -j12 or so, wasting time and
> resources. I have load-average set at 32, so if I were to set -j20
> generally
> I'd run out of RAM in no time. I've had many instances of packages failing
> to
> compile in a large update, but going just fine on their own; and I've had
> mysterious operational errors resulting, I suspect, from otherwise
> undetected
> miscompilation.
>
> Previous threads have more detail of what I've tried already.
>
>
> I did read all those but no matter how you move things around you still
have only X resources available all the time.
Whether you just let emerge do it's thing or try get it to do big packages
on their own, everything is still going to use the same number of cpu
cycles overall and you will save nothing.

If webkit-gtk is the only big package, have you considered:

emerge -1v webkit-gtk && emerge -avuND @world?


What you have is not a portage problem. It is a orthodox parallelism
problem, and I think you are thinking your constraint is unique in the work
- it isn't.
With parallelism, trying to fiddle single nodes to improve things overall
never really works out.

Just my $0.02


Alan

-- 
Alan McKinnon
alan dot mckinnon at gmail dot com

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