On Fri, Dec 9, 2011 at 3:39 PM, Thomas Rast <trast@xxxxxxxxxxxxxxx> wrote: > Well, just to make sure we're all left in a confused mess of partly > conflicting patches, here's another angle on the same thing: > > Jeff King wrote: >> Wow, that's horrible. Leaving aside the parallelism, it's just terrible >> that reading from the cache is 20 times slower than the worktree. I get >> similar results on my quad-core machine. > > By poking around in sha1_file.c I got that down to about 10. It's not > great yet, but it seems a start. > > The goal would be to improve it to the point where a patch lookup that > already has all relevant packs open and windows mapped can proceed > without locking. I'm not sure that's doable short of duplicating the > whole pack state (including fds and windows) across threads, but I'll > give it some more thought before going that route. Another potential user for parallel pack access is fsck. Although fsck access pattern may be different from grep, fsck would open and read through all packs. -- Duy -- To unsubscribe from this list: send the line "unsubscribe git" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html