Hi Matthias, Lately the reported issues have been more often race conditions or other bugs in the application side code rather than bugs in PoCL. These can appear as the program working as expected (by luck) in one OpenCL platform, but not the other.
Can you try with the latest version (3.0-RC1) and the latest LLVM to see if there's any difference? If it fails, a simplified reproducer is needed to track the issue - otherwise it's only guesswork. BR, Pekka On 5/20/22 00:56, Matthias Bock wrote:
Hi, I am experiencing an incorrect behaviour when running OpenCL kernels via pocl: I wrote an application in C/C++ calling kernels written in OpenCL C. It is a numerical simulation of the propagation of an electrical stimulus on tissue, from point to point on a 3D mesh with thousands of points. On one computer I run it with Intel's Open Source Beignet driver on an Ivy Bridge GT2 featuring 16 compute units. Calculation is time consuming, but the results are good: A wavefront of excitation forms and travels across the mesh as one would expect. When I run the identical source code with pocl on a machine featuring a Xeon L5640 showing 23 compute units, the results are completely different i.e. incorrect: The stimulus is not propagating in a wavefront, but instead wanders in random lines across the mesh. The platform is OpenCL 1.2 pocl 1.6, None+Asserts, LLVM 9.0.1, RELOC, SLEEF, DISTRO, POCL_DEBUG. The device is pthread-Intel(R) Xeon(R) CPU L5640 @ 2.27GHz OpenCL 1.2 pocl HSTR: pthread-x86_64-pc-linux-gnu-westmere. Unfortunately, I can't share the original source code, but I suspect some sort of race condition or the queue not being executed in the correct order. Inserting global memory barriers in all kernels and adding queue flush & finish calls in the main program after every kernel call didn't change anything though. Do you have any ideas or suggestions? Cheers, Matthias _______________________________________________ pocl-devel mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/pocl-devel
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