Planet GNOME

The All Systems Go! 2025 Call for Participation Closes Tomorrow!

The Call for Participation (CFP) for All Systems Go! 2025 will close tomorrow, on 13th of June! We’d like to invite you to submit your proposals for consideration to the CFP submission site quickly!

Good evening, hackfolk. A quick note this evening to record a waypoint in my efforts to improve Guile’s memory manager.

So, I got Guile running on top of the Whippet API. This API can be implemented by a number of concrete garbage collector implementations. The implementation backed by the Boehm collector is fine, as expected. The implementation that uses the bump-pointer-allocation-into-holes strategy is less good. The minor reason is heap sizing heuristics; I still get it wrong about when to grow the heap and when not to do so. But the major reason is that non-moving Immix collectors appear to have pathological fragmentation characteristics.

Fragmentation, for our purposes, is memory under the control of the GC which was free after the previous collection, but which the current cycle failed to use for allocation. I have the feeling that for the non-moving Immix-family collector implementations, fragmentation is much higher than for size-segregated freelist-based mark-sweep collectors. For an allocation of, say, 1024 bytes, the collector might have to scan over many smaller holes until you find a hole that is big enough. This wastes free memory. Fragmentation memory is not gone—it is still available for allocation!—but it won’t be allocatable until after the current cycle when we visit all holes again. In Immix, fragmentation wastes allocatable memory during a cycle, hastening collection and causing more frequent whole-heap traversals.

The value proposition of Immix is that if there is too much fragmentation, you can just go into evacuating mode, and probably improve things. I still buy it. However I don’t think that non-moving Immix is a winner. I still need to do more science to know for sure. I need to fix Guile to support the stack-conservative, heap-precise version of the Immix-family collector which will allow for evacuation.

So that’s where I’m at: a load of gnarly Guile refactors to allow for precise tracing of the heap. I probably have another couple weeks left until I can run some tests. Fingers crossed; we’ll see!

Damned Lies is the name of GNOME’s web application for managing localization (l10n) across its projects. But why is it named like this?

Damned Lies about GNOME

On the About page of GNOME’s localization site, the only explanation given for the name Damned Lies is a link to a Wikipedia article called “Lies, damned lies, and statistics”.

“Damned Lies” comes from the saying “Lies, damned lies, and statistics” which is a 19th-century phrase used to describe the persuasive power of statistics to bolster weak arguments, as described on Wikipedia. One of its earliest known uses appeared in a 1891 letter to the National Observer, which categorised lies into three types:

“Sir, —It has been wittily remarked that there are three kinds of falsehood: the first is a ‘fib,’ the second is a downright lie, and the third and most aggravated is statistics. It is on statistics and on the absence of statistics that the advocate of national pensions relies …”

To find out more, I asked in GNOME’s i18n Matrix room, and Alexandre Franke helped a lot, he said:

Stats are indeed lies, in many ways. Like if GNOME 48 gets 100% translated in your language on Damned Lies, it doesn’t mean the version of GNOME 48 you have installed on your system is 100% translated, because the former is a real time stat for the branch and the latter is a snapshot (tarball) at a specific time. So 48.1 gets released while the translation is at 99%, and then the translators complete the work, but you won’t get the missing translations until 48.2 gets released. Works the other way around: the translation is at 100% at the time of the release, but then there’s a freeze exception and the stats go 99% while the released version is at 100%. Or you are looking at an old version of GNOME for which there won’t be any new release, which wasn’t fully translated by the time of the latest release, but then a translator decided that they wanted to see 100% because the incomplete translation was not looking as nice as they’d like, and you end up with Damned Lies telling you that version of GNOME was fully translated when it never was and never will be. All that to say that translators need to learn to work smart, at the right time, on the right modules, and not focus on the stats.

So there you have it: Damned Lies is a name that reminds us that numbers and statistics can be misleading even on GNOME’s I10n Web application.