Re: Speed difference in Gnus

Stephen J. Turnbull wrote: what do you mean? as i said before, i have mostly finished code that will make text properties efficient by implementing them entirely in non-overlapping intervals, as fsf does. the problem with an extent covering the entire buffer is that it causes the "stack of extents" [soe] caching mechanism that determines which extents cover a particular position to entirely break down. i think the problem is that the current algorithm at least needs to examine all extents within the boundaries of the union of all extents covering the current position in order to find the correct set of extents overlapping an adjacent position. when there is an extent covering the whole buffer, all soe operations have to scan all extents in the buffer. i'm sure there are more sophisticated data structures to help with this problem, but in general this is a very tough problem, and using simpler solutions when possible (e.g. non-overlapping text properties). it might be possible to simulate extents in general using non-overlapping intervals, where multiple intervals could represent a single extent and each interval contains parts of all extents crossing over them. this interval would be guaranteed efficient and not too hard to implement, i think -- in fact it's the same algorithm i'd be using for text-properties, and could be extended to extents in general. but first we need some more profiling data. redisplay and certain other operations need to know about all extents covering a particular position, which is cached using a structure. map-extents, for example, when told to map over all extents overlapping a region, uses the soe structure to determine the bounds within which it needs to look. but when one extent covers the entire buffer, the current code that maintains the soe and moves it to adjoining buffer positions breaks down at least it is impossible to maintain the the caching info from the soe will be useless, and it will always have to uses ; but an extent over the entire buffer essentially invalidates this cache, since updating it requires looking over