Darktable Hangs with Intel OpenCL Enabled after Update to Kernel 6.8 + compute-runtime

[PorcelainMouse]

Since kernel 6.8 + compute-runtime, Intel A750 hasn't worked correctly. With kernel 6.7, BOINC was working well and no problems with Darktable were noticed. However, immediately after kernel 6.8, A750 wasn't even detected by BOINC. After an update to intel-compute-runtime recently, A750 is detected, but performance is much worse, power usage down by 90 % for the same workload. clpeak hangs.

I just tested Darktable, too, and it completely hangs with Intel OCL enabled, but works with Intel OCL disabled. I'm assuming this is due to the same underlying performance issue, but I thought I would report it because I couldn't see any other recent issues for darktable.

[ph0b]

Hi, I believe this is a duplicate of #726 that just got fixed.

[PorcelainMouse]

Awesome. I saw that, but wasn't sure. I'll try to get back on upstream kernel or at least try 6.9.

[ph0b]

if you have troubles with the current kernel on your system while waiting for the fix to land, you may work around the issue by using these environment variables:
NEOReadDebugKeys=1 NodeOrdinal=0 that will force all compute execution to run on the RCS (Render Command Streamer).

[eero-t]

Awesome. I saw that, but wasn't sure. I'll try to get back on upstream kernel or at least try 6.9.

As discussed in #726, you will need 6.10 kernel for full (= no perf regression) fix.

[eero-t]

Awesome. I saw that, but wasn't sure. I'll try to get back on upstream kernel or at least try 6.9.

As discussed in #726, you will need 6.10 kernel for full (= no perf regression) fix.

Which has also been released, few days ago: https://www.phoronix.com/news/Linux-6.10-Released

@PorcelainMouse Please verify / close when convenient.

[PorcelainMouse]

Yes, well, I'm on kernel 6.9.10 now. I got excited and thought I got 6.10 today. I re-enabled OCL & Intel OCL, restarted, it did some building of things, then I restarted it twice. No problems were noticed, seems to run smooth. But, if 6.10 is indicated, I'll revert back and wait some more. I haven't had time to get back to pulling from upstream kernel. It's just very inconvenient to manage that.

Thanks for the information, though! Much appreciated.

[PorcelainMouse]

Well, I have kernel 6.10, now, and dark table isn't hanging with Intel OCL enabled.

[eero-t]

Sorry for late reply.

Yes, well, I'm on kernel 6.9.10 now. I got excited and thought I got 6.10 today. I re-enabled OCL & Intel OCL, restarted, it did some building of things, then I restarted it twice. No problems were noticed, seems to run smooth. But, if 6.10 is indicated, I'll revert back and wait some more.

6.9 fixed the functional issue (hang), so AFAIK it should have already been useful, just potentially a bit slow due to performance regression in it (all compute engines might not get used), which was fixed in 6.10.