On 20 May 2012 22:49, Justin Lebar <justin.le...@gmail.com> wrote: > This patch lets ccache examine an include file's mtime and size in > lieu of hashing it, during direct mode. [...]
Cool. I've had this thought myself but never tried it out, partly because (as mentioned in the thread) it's quite brittle. > The net result is roughly a factor-of-two speedup in ccache hits (*), > on my machine. Same for me when running ccache's perf.py. > I'm not sure if we'd want mtime-snooping enabled by default. I think it's a feature worth having in ccache, but it needs to be disabled by default. Checking ctime as well sounds good, but I don't think we can rely on it - there are just too many strange file systems to consider. Somewhat related to this: I'm seriously considering making the whole direct mode opt-in as well in ccache 3.2 because of the design bug described in https://bugzilla.samba.org/show_bug.cgi?id=8728#c1. (Any ideas on how to fix the problem, or make it less likely, are welcome.) -- Joel _______________________________________________ ccache mailing list ccache@lists.samba.org https://lists.samba.org/mailman/listinfo/ccache
