From: A Large Angry SCM Date: Thu, 06 Aug 2009 23:35:32 GMT Subject: Re: [PATCH 0/5] Suggested for PU: revision caching system to significantly speed up packing/walking Message-ID: <4A7B68C4.8070406@gmail.com> In-Reply-To: <20090806203223.GK1033@spearce.org> Shawn O. Pearce wrote: > Nick Edelen wrote: >> Hrmm, I just realized that it dosn't actually cache paths/names... >> This obviously has no bearing on its use in packing, but I should >> either add that in or restrict usage in non-packing-related walks. >> Weird how things like that escape you. >> >> I think I may go ahead and add support for this tomorrow. It should >> have no effect on performance and very little impact on cache slice >> size. > > You may not need the path name, but instead the hash value that > pack-objects computes from the path name. All that matters is > the hash, so pack-objects can schedule the objects into the right > buckets when its doing delta computation for objects which are not > yet delta compressed, or whose delta cannot be suitably reused. > Please do NOT expose the hash values. The hash used by pack-objects is an implementation detail of the heuristics used by the _current_ object packing code. It would be a real shame to have to maintain backward compatibility with it at some future date after the packing machinery has changed.