Hi, On 17 August 2017 at 15:05, Karl Palsson <ka...@etactica.com> wrote: > xz has supported multithreaded compression since 5.2 in 2014. Enable > it's automatic support for this via the "-T 0" flag.
its ;p > > Previously: (xz -7e) > real 3m13.631s > > Now: (xz -T 0 -7e) > real 1m23.051s After playing around with it, it seems enabling multiple threads makes it compress slightly worse, at least in case of the linux kernel sources (86.8 MiB single thread vs. 87.7 MiB multithread). This means that the archive will have a different checksum, and thus affects reproducability. [1] suggests this is because of a different block size default, but unfortunately there seems to be no way to set the block size in an attempt to make it use the same one regardless of threads. If we still do this, I would suggest taking over the value from -j, so we don't use more cores than allowed, and you can force single threaded mode on a multi core system. Also ImageBuilder and Toolchain might profit from it as well. Regards Jonas [1] https://lists.debian.org/debian-dpkg/2016/10/msg00008.html _______________________________________________ Lede-dev mailing list Lede-dev@lists.infradead.org http://lists.infradead.org/mailman/listinfo/lede-dev
