Nicolas Pitre <nico@xxxxxxx> writes: > Given that the early eviction of objects with maximum delta depth > may exhibit bad packing on its own, why not considering a bias against > deep base objects in try_delta() to mitigate that bad behavior. This is really a good stuff. Thanks. Oh, and thanks for noticing my puzzlement expressed with "#if 0" ;-). > @@ -1038,8 +1038,8 @@ static int try_delta(struct unpacked *tr > > /* Now some size filtering euristics. */ > size = trg_entry->size; > - max_size = size / 2 - 20; > - if (trg_entry->delta) > + max_size = (size/2 - 20) / (src_entry->depth + 1); > + if (trg_entry->delta && trg_entry->delta_size <= max_size) > max_size = trg_entry->delta_size-1; > src_size = src_entry->size; > sizediff = src_size < size ? size - src_size : 0; At the first glance, this seems rather too agressive. It makes me wonder if it is a good balance to penalize the second generation base by requiring it to produce a small delta that is at most half as we normally would (and the third generation a third), or maybe the penalty should kick in more gradually, like e.g. ((max_depth * 2 - src_entry->depth) / (max_depth * 2). Having said that, judging from your past patches, I learned to trust that you have tried tweaking this part and settled on this simplicity and elegance, so I'll take the patch as is -- if somebody wants to play with it that can always be done to further improve things. - : 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