On Fri, 24 Feb 2006, Junio C Hamano wrote: > Nicolas Pitre <nico@xxxxxxx> writes: > > > Indexing based on adler32 has a match precision based on the block size > > (currently 16). Lowering the block size would produce smaller deltas > > but the indexing memory and computing cost increases significantly. > > Indeed. > > I had this patch in my personal tree for a while. I was > wondring why sometimes progress indication during "Deltifying" > stage stops for literally several seconds, or more. Note that above I'm saying that _keeping_ adler32 for small blocks is even longer. In other words, for small blocks, the version not using adler32 is about 3 times faster. I also noticed the significant slowdown after I made the improved progress patch. The idea now has to do with detecting patological cases and breaking out of them early. > In Linux 2.6 repository, these object pairs take forever to > delta. > > blob 9af06ba723df75fed49f7ccae5b6c9c34bc5115f -> > blob dfc9cd58dc065d17030d875d3fea6e7862ede143 > size (491102 -> 496045) > 58 seconds > > blob 4917ec509720a42846d513addc11cbd25e0e3c4f -> > blob dfc9cd58dc065d17030d875d3fea6e7862ede143 > size (495831 -> 496045) > 64 seconds Thanks for this. I'll see what I can do to tweak the code to better cope with those. Just keep my fourth delta patch in the pu branch for now. Nicolas - : 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