While rebuilding glibc-final on aarch64 I realized that the 'strip phase took 235 seconds. The relevant code for 'strip from gnu-build-system is in guix/build/gnu-build-system.scm, starting at line 340, with the actual stripping starting at 398. When I changed 'for-each' to 'par-for-each' the time dropped from 235 seconds to 215, about an 8.5% savings. I'm pretty sure most of that time was spent failing to strip certain files, but it is still a savings. I'm guessing there are other parts that can be parallelized in a similar manner. As for par-for-each (as many threads as cores on the machine) vs n-par-for-each (n threads), I think it would be better to use n-par-for-each, but I didn't quickly see a way to limit based on the number of cores offered to each builder. -- Efraim Flashner אפרים פלשנר GPG key = A28B F40C 3E55 1372 662D 14F7 41AA E7DC CA3D 8351 Confidentiality cannot be guaranteed on emails sent or received unencrypted