On Thursday, July 11, 2019 11:19 AM, Daniel Vetter <daniel@xxxxxxxx> wrote: > Aside: This all kinda doesn't go in the right direction for > high-performance composing, so I guess I need to get started with typing > up what that should look like. Some related logs from IRC: 2019-07-10 19:42:49 danvet ickle, is there an idiot guide to reasonable fast blending/composing with the cpu? 2019-07-10 19:43:13 danvet for vkms, so maitainability is high on the wishlist, but it needs to be somewhat fast to be able to keep up 2019-07-10 19:44:02 ickle pixman for rectangles 2019-07-10 19:45:00 ickle if you want reasonably fast, you want simd 2019-07-10 19:45:16 ickle so better to use some prebaked library 2019-07-10 19:45:38 ickle but within vkms? 2019-07-10 19:45:48 ickle or just for igt/vkms? 2019-07-10 19:46:40 ickle within vkms for writeback blending I guess 2019-07-10 19:51:38 ickle http://paste.debian.net/1091097/ 2019-07-10 19:53:08 ickle http://paste.debian.net/1091098/ 2019-07-10 19:54:36 emersion danvet: what are your plans for the compositor refactoring? 2019-07-10 19:55:21 emersion are we still really using macros instead of functions 2019-07-10 19:56:22 <-- nvishwa1 (~nvishwa1@192.55.54.44) has quit (Remote host closed the connection) 2019-07-10 19:56:44 emersion is this coming from pixman, ickle? 2019-07-10 19:56:50 --> karolherbst (~kherbst@2a02:8308:b0be:6900:d9e8:6dcd:2f6a:6cb5) has joined #intel-gfx 2019-07-10 19:57:23 ickle yes, take it as a reference on how to do abgr32 premultiplied alpha blending 2019-07-10 19:57:33 <-- amathes (ajmathes@nat/intel/x-ywywuftprrqndbaj) has quit (Ping timeout: 245 seconds) 2019-07-10 19:57:48 emersion yeah, that's a good idea 2019-07-10 19:57:49 ickle or argb32 actually 2019-07-10 19:58:01 emersion (asking for the source because license) 2019-07-10 19:58:04 ickle MIT 2019-07-10 19:58:07 emersion nice 2019-07-10 20:00:12 <-- sandeep (sandeep@nat/intel/x-buwbzkgopszvwbcr) has quit (Remote host closed the connection) 2019-07-10 20:01:34 danvet ickle, yeah vkms in the kernel 2019-07-10 20:02:41 danvet also might need more than 8 bits ... 2019-07-10 20:02:57 danvet and kinda hoped I could just tell gcc to simdify it for me 2019-07-10 20:03:23 danvet emersion, compositor refactoring 2019-07-10 20:03:46 danvet ickle, higher level I figured something like a fetch fifo in a standard format 2019-07-10 20:04:02 danvet with some drm_format->standard format conversion tools 2019-07-10 20:04:08 danvet and then one blender 2019-07-10 20:04:39 danvet and then either add that to the crc and toss it (again maybe scanline-by-scanline, or whatever fits reasonable into l1$ all together) 2019-07-10 20:04:44 danvet or dump it into writeback 2019-07-10 20:08:25 danvet https://gcc.gnu.org/onlinedocs/gcc/Vector-Extensions.html <- this stuff essentially, using generics 2019-07-10 20:08:38 danvet *generic intrinsics 2019-07-10 20:08:49 danvet or is that going to be real awful? 2019-07-10 20:09:35 ickle shouldn't be required for _basic_ blending 2019-07-10 20:09:52 danvet yeah I think all we want is premultiplied alpha 2019-07-10 20:09:53 ickle if all you need is an over operator, then gcc should be pretty good 2019-07-10 20:09:57 <-- sdutt (sdutt@nat/intel/x-zhquyrigdztslyqh) has quit (Ping timeout: 268 seconds) 2019-07-10 20:09:59 danvet maybe some yuv->rgb 2019-07-10 20:10:19 danvet expanding from whatever silly format we have to the right vector 2019-07-10 20:10:33 emersion what would be your universal format? 2019-07-10 20:10:46 danvet a16r16b16g16 2019-07-10 20:10:50 danvet except if gcc barfs on that 2019-07-10 20:11:02 danvet or maybe go all in on 4x float :-) 2019-07-10 20:11:10 emersion eh 2019-07-10 20:11:29 emersion fp16 would work, but would also mean rounding errors, probably? 2019-07-10 20:11:35 danvet uint16 is not going to be awesome for hdr, but good enough for everything else 2019-07-10 20:11:42 danvet no cpu has fp16 2019-07-10 20:11:52 emersion ah, fp32 2019-07-10 20:11:57 krh wait for avx1024 2019-07-10 20:12:01 emersion seems kind of overkill 2019-07-10 20:12:01 danvet fg32 is probably fastest option we can get on common hw 2019-07-10 20:12:12 danvet krh, very much aiming for good enough here 2019-07-10 20:12:26 ickle one plan is to sneak ksim into the kernel as generic gpu-on-x86 2019-07-10 20:12:52 krh can the kernel use avx2? 2019-07-10 20:13:05 danvet well, all stuff I'd need to figure out 2019-07-10 20:13:07 danvet I hope so 2019-07-10 20:13:12 ickle it can 2019-07-10 20:13:19 ickle easier than mmx 2019-07-10 20:13:49 emersion when you say gcc barfs on a16r16b16g16: why? 2019-07-10 20:13:57 danvet kernel_fpu_begin/end + telling gcc to optimize the crap out of the file with the blending functions 2019-07-10 20:14:11 emersion uint64 too hard for gcc to optimize? 2019-07-10 20:14:14 danvet emersion, I haven't checked, but if it generates silly code then might be better to go with fp32 2019-07-10 20:14:28 vsyrjala the compiler always generates silly code 2019-07-10 20:14:30 danvet ideally it should all boil down to sse/avx 2019-07-10 20:14:32 emersion ahah 2019-07-10 20:14:51 danvet and ideally all with generic intrinsics so the arm folks don't freak out 2019-07-10 20:15:07 --> sandeep (~sandeep@134.134.139.76) has joined #intel-gfx 2019-07-10 20:15:23 emersion +1 for generic intrinsics 2019-07-10 20:15:42 danvet the conversion from uint to fp32 might be hilarious 2019-07-10 20:15:50 emersion yeah, probably 2019-07-10 20:15:52 danvet perhaps the one place where we want to use an sse or avx intrinsic 2019-07-10 20:16:19 danvet especially if we convert to simd16 instead of something like 4x4 2019-07-10 20:16:22 emersion we should probably do some little experiments before doing anything 2019-07-10 20:16:24 danvet simd4x4 2019-07-10 20:16:31 danvet yeah 2019-07-10 20:16:41 danvet that's why I'm asking here, since I have roughly 0 clue about this 2019-07-10 20:17:48 danvet I don't think we ever need a dot or anything like that, so plain simd is propably best 2019-07-10 20:18:07 danvet except the input is usually 4x or 3x vectors 2019-07-10 20:18:07 emersion a dot? 2019-07-10 20:18:12 danvet dot product 2019-07-10 20:18:14 emersion ah 2019-07-10 20:18:15 danvet for vertex shaders 2019-07-10 20:18:20 emersion yeah, probably not 2019-07-10 20:18:21 bwidawsk danvet› btw, I think "generic intrinsic" is an ARM thing 2019-07-10 20:18:29 bwidawsk I think everywhere else, they just say intrinsic 2019-07-10 20:18:41 bwidawsk at least, I've never heard the generic prefix other than ARM compiler 2019-07-10 20:19:19 vsyrjala just make the max supported resolution 8x8 or something and speed shouldn't be a huge issue 2019-07-10 20:19:30 emersion i think he meant generic intrinsic vs. sse/avx/whatever 2019-07-10 20:19:49 bwidawsk emersion› yes, I figured out what he meant, I just mentioned it because it was a source of confusion 2019-07-10 20:19:52 emersion vsyrjala, helpful as always :) 2019-07-10 20:20:32 danvet oh gcc has all the casting implementing in the intrinsics too 2019-07-10 20:20:50 danvet bwidawsk, gcc manpage also calls them generic intrinsics 2019-07-10 20:21:25 bwidawsk danvet› not my gcc manpage 2019-07-10 20:21:40 danvet well "generic vector operations" 2019-07-10 20:21:46 danvet ^^ that what you meant? 2019-07-10 20:22:03 danvet vs "machine-specific vector intrinsics" 2019-07-10 20:22:38 bwidawsk I thought the generic intrinsic term came from ARM's proprietary compiler 2019-07-10 20:22:40 bwidawsk but I might be wrong _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/dri-devel
