On Sat, Nov 12, 2022 at 11:42:20PM +0100, Aurelien Jarno wrote: >... > On 2022-11-12 23:04, Adrian Bunk wrote: >... > > Sebastian, was there any real-world problem motivating your commit, > > or did it just sound more correct? > > > > With default settings there should be < 100 MB/core RAM usage, > > and even with "xz -9"[1] RAM usage should be < 700 MB/core. > > I think the use case there, is for the desktop. It's preferable to use 2 > threads only on a 4 core processor than sending Firefox to the swap. > That said that heuristics is not necessary the best for the build > daemon. >...
On a desktop that managed to successfully build a package large enough that multithreaded compression is even possible, why does it matter whether compression needs 200 MB or 400 MB of RAM? You can create a huge data package where the build just copies the data from the source package and then compresses with "xz -9", but the common case for big packages is C++ code where even in a single-threaded build g++ might need > 2 GB and then compressed with the default "xz -6". IOW, if building on a desktop that is so RAM-starved that this code would matter, I would expect that Firefox was already sent to swap during compilation. > Regards > Aurelien cu Adrian