On Thu, Dec 06, 2007 at 09:18:39AM -0500, Nicolas Pitre wrote: > > The downside is that the threading partitions the object space, so the > > resulting size is not necessarily as small (but I don't know that > > anybody has done testing on large repos to find out how large the > > difference is). > > Quick guesstimate is in the 1% ballpark.
Fortunately, we now have numbers. Harvey Harrison reported repacking the gcc repo and getting these results: > /usr/bin/time git repack -a -d -f --window=250 --depth=250 > > 23266.37user 581.04system 7:41:25elapsed 86%CPU (0avgtext+0avgdata > 0maxresident)k > 0inputs+0outputs (419835major+123275804minor)pagefaults 0swaps > > -r--r--r-- 1 hharrison hharrison 29091872 2007-12-06 07:26 > pack-1d46ca030c3d6d6b95ad316deb922be06b167a3d.idx > -r--r--r-- 1 hharrison hharrison 324094684 2007-12-06 07:26 > pack-1d46ca030c3d6d6b95ad316deb922be06b167a3d.pack I tried the threaded repack with pack.threads = 3 on a dual-processor machine, and got: time git repack -a -d -f --window=250 --depth=250 real 309m59.849s user 377m43.948s sys 8m23.319s -r--r--r-- 1 peff peff 28570088 2007-12-06 10:11 pack-1fa336f33126d762988ed6fc3f44ecbe0209da3c.idx -r--r--r-- 1 peff peff 339922573 2007-12-06 10:11 pack-1fa336f33126d762988ed6fc3f44ecbe0209da3c.pack So it is about 5% bigger. What is really disappointing is that we saved only about 20% of the time. I didn't sit around watching the stages, but my guess is that we spent a long time in the single threaded "writing objects" stage with a thrashing delta cache. -Peff
