The first two patches are posted already, which help keep memory usage down in the present of large blobs. The forth patch attempts to resolve deltas in parallel. $ time ./git index-pack --threads=1 --verify -v XXXX Indexing objects: 100% (165375/165375), done. Resolving deltas: 100% (124749/124749), done. real 1m15.470s user 1m14.899s sys 0m0.552s $ time ./git index-pack --threads=2 --verify -v XXXX Indexing objects: 100% (165375/165375), done. Resolving deltas: 100% (124749/124749), done. real 0m41.339s user 1m15.116s sys 0m0.680s $ time ./git index-pack --threads=3 --verify -v XXXX Indexing objects: 100% (165375/165375), done. Resolving deltas: 100% (124749/124749), done. real 0m37.008s user 1m35.742s sys 0m0.803s $ time ./git index-pack --verify -v XXXX # four core machine Indexing objects: 100% (165375/165375), done. Resolving deltas: 100% (124749/124749), done. real 0m33.701s user 1m51.316s sys 0m0.768s $ time ./git index-pack --threads=8 --verify -v XXXX Indexing objects: 100% (165375/165375), done. Resolving deltas: 100% (124749/124749), done. real 0m33.638s user 1m51.783s sys 0m0.773s So there's improvement from user persepective, but overhead is too high (user time from 1m14 to 1m51). Making threaded_second_pass to process 512 consecutive objects each iteration to reduce contention on work_mutex does not help. Any ideas? Nguyễn Thái Ngọc Duy (4): index-pack --verify: skip sha-1 collision test index-pack: reduce memory usage when the pack has large blobs index-pack: move second pass code into separate function index-pack: support multithreaded delta resolving Documentation/config.txt | 4 + Documentation/git-index-pack.txt | 10 ++ Makefile | 2 +- builtin/index-pack.c | 298 +++++++++++++++++++++++++++++++------- 4 files changed, 260 insertions(+), 54 deletions(-) -- 1.7.8.36.g69ee2 -- 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