Han-Wen Nienhuys <hanw...@gmail.com> writes: > On Sun, Dec 13, 2009 at 12:13 PM, Graham Percival > <gra...@percival-music.ca> wrote: >> On Sun, Dec 13, 2009 at 2:00 PM, Neil Puttock <n.putt...@gmail.com> wrote: >>> 2009/12/13 Mark Polesky <markpole...@yahoo.com>: >>> >>>> Is there a way to improve this? I don't want to put too >>>> much extra stress on CPU1 if I run `make check' alot. Or am >>>> I being paranoid? >>> >>> make -j5 CPU_COUNT=5 check >> >> Be warned that sometimes lilypond-book has hash collisions in the >> filename, which can lead to weird compile errors when one process >> finished dealing with aa/lily-aaaa.ps (and thus deletes it), while >> another process has finished generating aa/lily-aaaa.ps but hasn't >> started running ps2pdf yet, and thus doesn't find the file that it >> just wrote. > > Do you have real evidence for that? We use 10 hex digits, yielding > 2^40 combinations, so a 2^20 (one in a million) chance of collisions.
If we are talking about 2 particular files colliding. If we are talking about a collision in n files, there are n(n+1)/2 combinations all of which have a 2^20 chance of collision (of course, those are not independent collisions, but the approximation is pretty good). A 1% chance of collision is (first order approximation) achieved when n(n+1)/2=10000, meaning n is something like 140. Close enough to make 40 bits feel uncomfortable. -- David Kastrup _______________________________________________ lilypond-devel mailing list lilypond-devel@gnu.org http://lists.gnu.org/mailman/listinfo/lilypond-devel
