I'm planning to release a v2 for buffer objects. Can we get the naming scheme decided upon? I suggest mesa buffer data fallback. On Feb 3, 2015 10:30 AM, "Kristian Høgsberg" <[email protected]> wrote:
> On Mon, Feb 2, 2015 at 11:59 AM, Thomas Helland > <[email protected]> wrote: > > 2015-02-02 19:18 GMT+01:00 Jason Ekstrand <[email protected]>: > >> Hi all, > >> I wanted to send out a quick message about naming conventions for mesa > >> entrypoints and dd table fallbacks. There has been some confusion and > >> disagreement about this with some of the stuff Laura has been doing to > >> implement DSA. Instead of side-track one of those patches for this > >> discussion, I thought it was worth its own e-mail. > >> > >> When Laura started working on DSA, I suggested that, since we're > refactoring > >> everything anyway, we refactor the guts of the entrypoint into a > DSA-style > >> "internal entrypoint". This internal entrypoint takes a gl_context > pointer, > >> does less error checking, and actual mesa object pointers instead of > GLuint > >> names. I'll get to why in a minute here. However, that leaves us > needing a > >> naming convention for three things: > >> > >> 1) The entrypoint itself (currently _mesa_EntryPoint) > >> 2) the internal entrypoint (Laura chose _mesa_entry_point) > >> 3) the software fallback for the DD table entry (Laura chose > >> _mesa_TableEntry_sw) > >> > >> I think we can all agree on not changing (1). Previously we had > something > >> of a convention of _mesa_entry_point for (3) but it wasn't perfectly > >> consistent. Since we didn't have DSA, we didn't have anything for (2). > >> Personally, I'm OK with what Laura chose, but I understand that it's a > >> change of convention. Another option, would be to do > _mesa_main_TableEntry > >> or _mesa_main_table_entry for the standard DD fallback. Or we can come > up > >> with a different convention for the internal entry points. I don't care > >> much. > >> > >> Why the internal entrypoints? > >> > >> The first reason is that we have to do the refactor anyway, and that > seems > >> reasonable. The more important reason is meta. This is something that > >> Kristian, Ken and I have talked about a good bit lately. I've done some > >> traces with meta lately and meta_begin/end show up a lot and what shows > up > >> more is hash table lookups and, in particular, the mutex lock/unlock > that's > >> involved. Inside meta, we do all sorts of stupidity like > > > > Kind of off-topic, but since you're mentioning overhead of hash tables: > > I've been doing some work on util/hash_table that is yet to be sent to > the list. > > Thought I could share my experience if someone happens to be > > working on other improvements to the hash-tables. > > > > TLDR of approach: > > Power-of-two sized table instead of prime size. > > -> We can replace the modulo with bitmasking to fit keys in the table. > > -> Reduced overhead on insert, search, resize, etc. > > -> FNV-1a has good avalanche properties -> collisions is a no-issue. > > > > Changing to quadratic probing removes the rehash-stuff. > > -> Less code, simpler, seems to do a better job. > > -> Reduced memory usage and better cache locality? > > > > Preliminary oprofile results of a shader-db run with NIR: > > > > hash_table_insert: 4.13 % --> 2.13 % > > hash_table_search: 4.12 % --> 2.29 % > > > > To be done: > > Do the same for hash set. > > Change some hash table uses to the one in util. > > Similar treatment for the other tables. > > Test on something that is actually CPU bound. > > Yeah, I was never convinced that the prime size hashtables provided > any benefit. Sounds good to me looking forward to seeing the patches. > > Kristian > > > -Thomas Helland > > _______________________________________________ > > mesa-dev mailing list > > [email protected] > > http://lists.freedesktop.org/mailman/listinfo/mesa-dev > _______________________________________________ > mesa-dev mailing list > [email protected] > http://lists.freedesktop.org/mailman/listinfo/mesa-dev >
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