AMD EPYC Turin Power Profile Selection Impact On Performance & Efficiency

Last week I published an article looking at the power efficiency of 5th Gen AMD EPYC “Turin” using the modern AMD P-State driver and the Power Profile options. The AMD P-State driver being used by default now for the EPYC 9005 series processors on Linux 6.12+ and paired with Power Profile option tuning can deliver a nice boost to server energy efficiency with only modest impact to the performance. Today’s article are some complementary numbers I carried out recently on a Supermicro server looking at more of the Power Profile Selection options.

Two new site features: full-text RSS and automatic dark mode

One of the often-requested LWN site features that has languished the
longest on our to-do list is full-text RSS feeds. We are happy to announce
that, finally, there is a set of such feeds available; the full set can be
seen on our feeds page. This is a
subscriber-only feature, and it works by creating a unique fetch URL for
each user. We will, of course, be counting on our readers to not share
those URLs.

Another feature we have had requests for is to automatically present the
site in dark-mode colors when a reader’s browser has been configured to
prefer it. That feature, too, is now available. In this case, we had to
think about the interaction between automatic selection and the color
customization that the site has long had. The conclusion we reached is
that, if custom colors have been configured for an account, they will win
out over the automatic selection. There is a new preference in the customization area to change this
default if desired.

Both of these features — and the other enhancements we have made recently —
were enabled by the support of LWN’s subscribers. By making it possible to
bring in new staff last year, you created the space to improve the site
experience while keeping up with the writing. We thank all of you for your
support.

[$] Python interpreter adds tail calls

The

Faster CPython project
has been working to speed up the Python interpreter
for the past several years. Now, Ken Jin, a member of the project, has merged a

new set of changes
that
have been

benchmarked
as improving performance by 10% for some architectures.
The only change is switching from using computed goto statements to using
tail calls as part of the implementation of Python’s bytecode interpreter — but that change allows
modern compilers to generate significantly better code.

Eternal Vigilance

At the moment things are still tense; we deal with violent Microsoft con jobs (American citizens) and their “hired guns from London” sending unauthorised and totally inappropriate messages to our lawyer, basically trying to not only threaten but also spy