MacOS X 10.10 talos numbers now way more stable... but why?

[William Lachance]

Hey all,

As Joel noted in bug 1191019
(https://bugzilla.mozilla.org/show_bug.cgi?id=1191019#c12), the MacOS X
10.10 talos numbers got a *lot* more stable recently. This makes me
happy, as it makes it a lot easier to catch MacOS X regressions, in fact
I just filed one yesterday
(https://bugzilla.mozilla.org/show_bug.cgi?id=1228439) which we probably
wouldn't have caught with the old setup.

Two things though:

1. Are these changes being logged somewhere? It's very difficult to do
performance sheriffing properly unless I have a clear idea of what's
changing and when. I had a vague idea that MacOS X 10.10 would be
changing, but I feel like this caught me by surprise.

I will admit that my mind is not on this stuff much (I spend about 95%
of my time @ Mozilla hacking on Perfherder), but I think that would go
for the volunteer sheriffs that we eventually want to recruit to help
out with this stuff too.

2. Does anyone have a clear idea *why*, specifically, these numbers are
so much more stable than before? Are OS version + hardware the only
things we changed, or were there some other configuration changes that
came along for the ride?

Anyway, congratulations to the people involved. This is a big step
forward. \o/

Will

[jma...@mozilla.com]

I recall looking into the ARP's coming from OSX used for itunes,etc. and we had a storm of them. I think more on reboots. the M-DNS tools were changed (to the older more stable form) in 10.10.5. I am sure there are many other differences, but this is one that I recall. I am sure others can correct me as I am bound to mess up some TLA on something I know very little about :)

-Joel