Hi Maxime, Thanks for looking at optimising stuff. :-) On Sun, 05 Sep 2021 at 21:48, Maxime Devos wrote: > Let's compare the numbers again! This time, I've run > > echo powersave |sudo tee /sys/devices/system/cpu/cpufreq/policy{0,1,2,3}/scaling_governor > > to make sure the CPU frequency doesn't change. On a hot (disk) cache: > > # After the patch series > time GUIX_PROFILING="rpc gc" ./the-optimised-guix/bin/guix build -d --no-grafts pigx [...] > So on a hot disk cache, there doesn't appear to be any improvement > (except for ‘time spent in GC’ -- presumably that's due to the optimisations > to guix/base32.scm). Which kind of disk do you have? SSD, spinning HDD, other? > What about a cold cache? > > # After the patch series > > sync && echo 3 | sudo tee /proc/sys/vm/drop_caches > ./the-optimised-guix/bin/guix --help > time GUIX_PROFILING="rpc gc" ./the-optimised-guix/bin/guix build -d --no-grafts pigx > /gnu/store/fq6x8d2vcm6sbjkimg7g8kcgb4c5xv1b-pigx-0.0.3.drv > Remote procedure call summary: 5949 RPCs > built-in-builders ... 1 > add-to-store ... 3 > add-to-store/tree ... 26 > add-temp-root ... 195 > valid-path? ... 195 > add-text-to-store ... 5529 > Garbage collection statistics: > heap size: 93.85 MiB > allocated: 312.03 MiB > GC times: 17 > time spent in GC: 3.37 seconds (23% of user time) > > real 1m39,178s > user 0m14,557s > sys 0m0,990s How the average (against 3 examples) looks like? > It seems that if the disk cache is cold, the time-to-derivation decreases > a little by this patch series. Much less than I had hoped for though; I'll > have to look into other areas for interesting performance gains ... Please update the number using your diff showed in [1]. :-) 1: All the best, simon