>This patch lets ccache examine an include file's mtime and size in >lieu of hashing it, during direct mode. If the mtime and size don't >match, we fall back to hashing. > >The net result is roughly a factor-of-two speedup in ccache hits (*), >on my machine. > >I'm not sure if this is a desirable feature, because obviously mtimes >can be tampered with.
IMO I at my site I would be reluctant to use ccache with this enabled, and believe the default should be as safe as possible. I've been burned by mtime only checking before as (excluding some recent file systems) mtime has a resolution only down to one second. However including it as an option seems fine, and recording it into the manifest also seems good. I would also suggest making the manifest format backward compatible when it is easy as in this case; just test the version number when reading the file. _______________________________________________ ccache mailing list firstname.lastname@example.org https://lists.samba.org/mailman/listinfo/ccache