28 Feb
2025
28 Feb
'25
7:35 p.m.
At Fri, 28 Feb 2025 12:09:49 -0500, Dennis Boone <drb(a)msu.edu> wrote:
Subject: [TUHS] Re: VM over-commit (and the OOM killers)
I was told a few years ago by a smart person I respect that one of the
reasons Mac laptops were still so poorly endowed with RAM (iirc 8 GB
max) was because Apple was shipping SSD in them, so the performance hit
wasn't really noticeable. One hopes those were sturdy (DWPD) SSDs, but
barring the marketing decisions (removing ports people want), Apple's
hardware engineering is usually decent.
That's probably mostly true, but also misguided and ignorant of the
actual behaviour of RAM-starved systems. I suspect it was policy based
on memory prices at some time in the past, but seemingly hasn't been
re-evaluated for modern workloads more recently.
MacOS has long been OK at handling a little bit of paging, but seems to
get to the state of thrashing far sooner than one would expect it to. I
find Apple's default memory provisioning to be half as big as it should
be for the real-world uses most people encounter, especially these days
with the bloatware that is modern desktop software (especially browsers!)
On my BSD systems I always allocate lots of swap space (I try for at
least as much as I have RAM, if not more), but I get worried any time I
see any of it used. As Warner said, it's fine for transient loads, but
if a system starts paging during regular production loads then I have a
big problem.
--
Greg A. Woods <gwoods(a)acm.org>
Kelowna, BC +1 250 762-7675 RoboHack <woods(a)robohack.ca>
Planix, Inc. <woods(a)planix.com> Avoncote Farms <woods(a)avoncote.ca>