Hi, On Sun, 11 Nov 2012, Jeff King wrote:
> On Sun, Nov 11, 2012 at 05:46:32PM +0100, René Scharfe wrote: > > > >However, I couldn't reproduce it on Linux : where the windows > > >implementations crashes at a ~32000 depth (*not* exactly 32768, mind > > >you), on linux it happily went through 100000 commits. I didn't take > > >time to look much further, but maybe on my 64 bit Linux VM, the > > >process can afford to reserve a much bigger address range for the > > >stack of each thread than the 1Mb given to 32 bit processes on > > >windows. Jean-Jacques. > > > > I can reproduce it on Linux (Debian testing amd64) with ulimit -s 1000 > > to reduce the stack size from its default value of 8MB. > > > > After reverting ffc4b8012d9a4f92ef238ff72c0d15e9e1b402ed (tag: speed > > up --contains calculation) the test passes even with the smaller > > stack, but it makes "git tag --contains" take thrice the time as > > before. > > Right, I am not too surprised. That function replaced the original > algorithm with a much faster depth-first recursive one. I haven't looked > closely yet at Jean-Jacques' iterative adaptation, but that direction > seems like a good fix for now. > > Ultimately, I have some ideas for doing this in a breadth-first way, > which would make it more naturally iterative. It would involve having N > bits of storage per commit to check N tags, but it would mean that we > could get accurate answers in the face of clock skew (like the > merge-base calculation, it would merely get slower in the face of skew). > > But since I haven't worked on that at all, fixing the depth-first > algorithm to be iterative makes sense to me. Have you tried the latest tag-contains branch of git://github.com/msysgit/git/? It contains a couple of brush-ups and a re-write of the recursion (which I hope is right, I had only time to work on it during an unwanted layover at O'Hare). The SHA-1 is fc4f42787a0dd0022d202627681362081a66ef70. Ciao, Johannes