On Fri, May 3, 2013 at 8:35 AM, Nguyễn Thái Ngọc Duy <pclo...@gmail.com> wrote: > In order to make sure the cloned repository is good, we run "rev-list > --objects --not --all $new_refs" on the repository. This is expensive > on large repositories. This patch attempts to mitigate the impact in > this special case. > > In the "good" clone case, we only have one pack. If all of the > following are met, we can be sure that all objects reachable from the > new refs exist, which is the intention of running "rev-list ...": > > - all refs point to an object in the pack > - there are no dangling pointers in any object in the pack > - no objects in the pack point to objects outside the pack > > The second and third checks can be done with the help of index-pack as > a slight variation of --strict check (which introduces a new condition > for the shortcut: pack transfer must be used and the number of objects > large enough to call index-pack). The first is checked in > check_everything_connected after we get an "ok" from index-pack. > > "index-pack + new checks" is still faster than the current "index-pack > + rev-list", which is the whole point of this patch. If any of the > conditions fails, we fall back to the good old but expensive "rev-list
s/fails/fail/ > ..". In that case it's even more expensive because we have to pay for > the new checks in index-pack. But that should only happen when the > other side is either buggy or malicious. > > Cloning linux-2.6 over file:// > > before after > real 3m25.693s 2m53.050s > user 5m2.037s 4m42.396s > sys 0m13.750s 0m16.574s > > A more realistic test with ssh:// over wireless > > before after > real 11m26.629s 10m4.213s > user 5m43.196s 5m19.444s > sys 0m35.812s 0m37.630s > > This shortcut is not applied to shallow clones, partly because shallow > clones should have no more objects than a usual fetch and the cost of > rev-list is acceptable, partly to avoid dealing with corner cases when > grafting is involved. > > Signed-off-by: Nguyễn Thái Ngọc Duy <pclo...@gmail.com> -- To unsubscribe from this list: send the line "unsubscribe git" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
