[Bf-cycles] Breaking news, OpenCL work on my AMD 5670 on linux x86_64

T S kartochka22 at yandex.ru
Sat Dec 24 15:09:16 CET 2011

Just a little additional info.

I suspect AMD OpenCL compiler bugs are main reason of crashes, I doubt we can workaround them. What i do now i trying to guess minimal subset of features to make it somwhat work, just to test my own code is it work at all on GPU(that important for me, i have no chance to test it before). I commenting some cases in shader interpretator in svm.h, one-by one, trying to isolate code that make internal AMD compiler hardlock GPU.

As a side note, i experience very suspisious behavior of compiler time. When i disable my "precious" volume subset (by commenting out MY_VOLUME definition in kernel_type.h), compiling kernel took 8-14 seconds looking at message in terminal, but really it compile longer, maybe 30 sec or more. But if i uncomment volume patch, it compile 6+ _MINUTES_. perf top say most time spend in glibc strstr, memchr, memset. After another change, i got 11 GB blender virtual memory usage, terrific swap storm, but no crash, i wait 40 minutes staring at vmstat output, it sloooly decrease from 11 GB to 2, then start to grow again, i killl task. I guess maybe AMD compiler so buggy, it desighned only for tiny DSP-like kernel and fail miserable in our case, big program have O(N*N) or worse time. strstr search substring, obviously it have problem even on preprocessor stage.

Ideally, we must push AMD, thats all. I got crashes in COMPILER (crachdump point deep inside AMD binary library), then GPU hardlocks (can only move mouse, KB locked, can ssh from other computer, blender take 99% cpu time, any try to strace , attach gdb, kill -15, kill -9 are all ignored. Only hardware reset work).

Jens, thanx for testing, but it is not that new on Apple, as i understend Apple already worked with resent revisions (1-2 weeks), may be with less features, main goal was make it work at linux with that proprietary binary blob.

Textures are disabled with that patch completely, i make subset that work with wave and gradient, as always, when i going to post updated patch my computer go crazy, after another lokup (trying to add musgrave texture) it start to glitching, artefacts on screen, even GDM theme changed to basic after reboot. I suspect overheat or other things, so no new patches for now, maybe later. (Wohoo, volume patch killing hardware! :) )

Speed is very bad BTW, so-so as 4 core Phenom. Need to profile GPU to search bottleneck.

24.12.2011, 16:10, "Jens Verwiebe" <info at jensverwiebe.de>:
> Hi
> I used Storms patch and played a bit with.
> On Apple turned out with my ATI 5870 i get now:
> - shaders
> - emission on meshes
> Can´t use textures right now, always RGB input for the moment. Have to investigate a bit more, but
> this is a good find !!
> A bit of evidence: http://www.jensverwiebe.de/Blender/Bildschirmfoto%202011-12-24%20um%2010.41.16.jpg
> Merry Christmas, hohoho and all this ;)
> Jens
> _____________________________________
> Jens Verwiebe
> Allerskehre 44  -  22309 Hamburg
> Tel.: +49 40 68 78 50
> mobil: +49 172 400 49 07
> mailto: info at jensverwiebe.de
> web:  http://www.jensverwiebe.de
> _____________________________________
> _______________________________________________
> Bf-cycles mailing list
> Bf-cycles at blender.org
> http://lists.blender.org/mailman/listinfo/bf-cycles

More information about the Bf-cycles mailing list