On Sunday 19 January 2014 11:59:36 Mike Gilbert wrote:
> On Sun, Jan 19, 2014 at 4:44 AM, Mike Frysinger <vapier@gentoo.org> wrote:
> > Chromium OS for a long time was restricted to EAPI 4 for two reasons --
> > it had an old portage version (and upgrading to a newer one regressed
> > performance significantly, so we held off until we could figure out why)
>
> I am curious to know more about the performance regression if you can
> share. Is that something that got fixed, or did you disable some
> features (like the slot-operator stuff)?

we finally tracked it down (was due to new the new FEATURES=merge-sync option.
when you're installing 200 to 500 binary packages (with like 32 in parallel),
that can easily choke your throughput.  some systems saw really excessive
latencies (which i would guess was due to their drive taking longer to process
dirty blocks).  but it took us some time to figure that out as we were making a
large version jump and we didn't have too much time to dedicate to tracking it
down.  lots o bugs to fix.
-mike