Hi, On Sat, Jul 21, 2012 at 09:25:50PM +0300, Uoti Urpala wrote: > Joey Hess wrote: > > Hideki Yamane wrote: > > > I tested as well, and sometimes decompression with xz is so sloooow, > > > it takes 6-8 times than default gz. > > > > I was just watching your DebConf presentation "Lets shrink Debian > > package archive" and I think there you said decompression with xz was > > between 2x and 6x slower. Is that the current number? > > > > I'm concerned with the thought that installation of Debian (as well > > as debootstrap) could take twice or more as long if xz were used for > > say, every package on a Gnome desktop CD. In d-i we try to make > > installation faster; slow installs make people less happy. It would > > be useful to have some real-world installation time benchmarks with > > and without xz. > > Does unpacking really take a substantial portion of the time used by the > installer? [..] > So at least in this case the biggest performance problem by far is the > inappropriate use of fsync() or other disk synchronization primitives, > and CPU use for unpacking is pretty much irrelevant.
Though the kernel will have to sync sooner or later, I understand debian-installer ask dpkg not to fsync: http://bugs.debian.org/605384 base-installer (1.121) unstable; urgency=low . [ Colin Watson ] * Merge from Ubuntu: - Run dpkg with --force-unsafe-io during installation; syncing is unnecessary in this context and can slow things down quite a bit (closes: #605384). -- Simon Paillard -- To UNSUBSCRIBE, email to debian-devel-requ...@lists.debian.org with a subject of "unsubscribe". Trouble? Contact listmas...@lists.debian.org Archive: http://lists.debian.org/20120721224210.gj5...@glenfiddich.mraw.org
