news
New Articles in LWN (Outside Paywall Today)
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Python
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LWN ☛ Python performance myths and fairy tales
Antonio Cuni, who is a longtime Python performance engineer and PyPy developer, gave a presentation at EuroPython 2025 about "Myths and fairy tales around Python performance" on the first day of the conference in Prague. As might be guessed from the title, he thinks that much of the conventional wisdom about Python performance is misleading at best. With lots of examples, he showed where the real problems that he sees lie. He has come to the conclusion that memory management will ultimately limit what can be done about Python performance, but he has an early-stage project called SPy that might be a way toward a super-fast Python.
He started by asking the audience to raise their hands if they thought ""Python is slow or not fast enough""; lots of hands went up, which was rather different than when he gave the presentation at PyCon Italy, where almost no one raised their hand. ""Very different audience"", he said with a smile. He has been working on Python performance for many years, has talked with many Python developers, and heard some persistent myths, which he would like to try to dispel.
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Applications
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LWN ☛ The NNCPNET email network
Running a modern mail server is a complicated business. In part, this complication is caused by the series of incrementally developed practices designed to combat the huge flood of spam that dominates modern email communication. An unfortunate side effect is that it prevents people from running their own mail servers, concentrating people on a few big providers. NNCPNET is a suite of software written by John Goerzen based on the node-to-node copy (NNCP) protocol that aims to make running one's own mail servers as easy as it once was. While the default configurations communicates only with other NNCPNET servers, there is a public relay that connects the system to the broader internet mail ecosystem.
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NNCP is a spiritual successor to the unix-to-unix copy protocol (UUCP) in the same way that SSH is a spiritual successor to rsh. Sergey Matveev created the project to be an easier to use, more secure replacement for UUCP. Like its predecessor, NNCP is both a (relatively simple) protocol, and a suite of reusable single-purpose command-line tools. The project's code is licensed under the GPLv3.
As with early computer networks, routing in NNCP is manual. In order to contact a host, the user needs to explicitly tell NNCP what routes are available to connect to it. In modern parlance, that makes it a friend-to-friend network, where each computer connects only to computers that the owner knows about and trusts. This makes it impossible to tell exactly how many people are using NNCP, because there's no network-wide consensus on membership. Routes may also be indirect: if two servers aren't directly connected, but they both know how to reach some third server, they can be configured to talk to each other via the third server. This avoids the need for explicit bang paths in each email, but is still a form of manual routing. In practice, many users likely have a connection to the quux.org server operated by Goerzen for this purpose.
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Debian
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LWN ☛ Don't fear the TPM
There is a great deal of misunderstanding, and some misinformation, about the Trusted Platform Module (TPM); to combat this, Debian developer Jonathan McDowell would like to clear the air and help users understand what it is good for, as well as what it's not. At DebConf25 in Brest, France, he delivered a talk about TPMs that explained what they are, why people might be interested in using them, and how users might do so on a Debian system.
McDowell started with a disclaimer; he was giving the talk in his personal capacity, not on behalf of his employer. He wanted to talk about ""something that is useful to Debian and folks within Debian"", rather than the use of TPMs in a corporate environment.
McDowell has been a Debian developer for quite some time—more than 24 years, in fact. Professionally, he has done a lot of work with infrastructure; he has written networking software, high-end storage systems, and software-defined networking. He has also run an ISP. To him, TPMs are simply ""another piece of infrastructure and how we secure things"".
Unfortunately, there is a lot of FUD around TPMs, he said, especially now that Microsoft is pushing TPM devices as part of the baseline requirement for Windows 11. That has been part of the baseline since it was introduced, of course, but with the end-of-life approaching for Windows 10 people are starting to take more notice.
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LWN ☛ Debian grapples with offensive packages, again
A pair of packages containing fortune "cookies" that were deemed offensive have been removed from the upcoming Debian 13 ("trixie") release. This has, of course, led to a lengthy discussion and debate about what does, or does not, belong in the distribution. It may also lead to a general resolution (GR) to decide whether Debian's code of conduct (CoC) applies to the contents of packages.
The fortune program prints out a random quote or other piece of text from one or more topic databases. On Debian, for example, the topic categories shipped with the fortunes package include art, ascii-art, food, love, Linux, pets, Star Trek, and more. Those are installed by default when one installs fortune-mod, the package that contains the fortune program.
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Kernel
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LWN ☛ [Linux] 6.17 Merge window, part 1
As of this writing, just over 4,000 non-merge changesets have been pulled into the mainline repository during the 6.17 merge window. When he announced the merge-window opening, Linus Torvalds let it be known that, due to a busy personal schedule, he was likely to pull changes more quickly than usual this time around; that has been borne out to some extent. Changes merged so far are focused on core-kernel and filesystem work; read on for the details.
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LWN ☛ Improving control over transparent huge page use
The use of huge pages can significantly increase the performance of many workloads by reducing both memory-management overhead in the kernel and pressure on the system's translation lookaside buffer (TLB). The addition of transparent huge pages (THP) for the 2.6.38 kernel release in 2011 caused the kernel to allocate huge pages automatically to make their benefits available to all workloads without any effort needed on the user-space side. But it turns out that use of huge pages can make some workloads slower as the result of internal memory fragmentation, so the THP feature is often disabled. Two patch sets aimed at better targeting the use of transparent huge pages are currently working their way through the review process.
Over the years, the kernel has evolved a number of ways to control the use of THP; they are described in Documentation/admin-guide/mm/transhuge.rst. At the global level, the /sys/kernel/mm/transparent_hugepage/enabled knob controls behavior system-wide. It can be set to "always" or "never" with obvious results. This knob also supports the "madvise" setting, which only enables THP for processes that explicitly opt in for specific memory regions with a call to madvise(). The kernel, in other words, allows for the imposition of a system-wide policy, with the possibility of restricting THP usage to places where applications have explicitly enabled it.
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