[Openmp-commits] [openmp] [amdgpu][openmp] Treat missing TIMESTAMP_FREQUENCY as non-fatal (PR #70987)

[via Openmp-commits]

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-backend-amdgpu

Author: Jon Chesterfield (JonChesterfield)

<details>
<summary>Changes</summary>

If you build with dynamic_hsa, the symbol is known and compilation succeeds. If you then run with a slightly older libhsa, this argument is not recognised and an error returned. I'd rather the program runs with a misleading omp wtime than refuses to run at all.

---
Full diff: https://github.com/llvm/llvm-project/pull/70987.diff


1 Files Affected:

- (modified) openmp/libomptarget/plugins-nextgen/amdgpu/src/rtl.cpp (+6-4) 


``````````diff
diff --git a/openmp/libomptarget/plugins-nextgen/amdgpu/src/rtl.cpp b/openmp/libomptarget/plugins-nextgen/amdgpu/src/rtl.cpp
index 71207f767fdcc60..378cad8f8ca4f15 100644
--- a/openmp/libomptarget/plugins-nextgen/amdgpu/src/rtl.cpp
+++ b/openmp/libomptarget/plugins-nextgen/amdgpu/src/rtl.cpp
@@ -1810,10 +1810,12 @@ struct AMDGPUDeviceTy : public GenericDeviceTy, AMDGenericDeviceTy {
       return Err;
     GridValues.GV_Warp_Size = WavefrontSize;
 
-    // Get the frequency of the steady clock.
-    if (auto Err = getDeviceAttr(HSA_AMD_AGENT_INFO_TIMESTAMP_FREQUENCY,
-                                 ClockFrequency))
-      return Err;
+    // Get the frequency of the steady clock. If the attribute is missing
+    // assume running on an older libhsa and default to 0, omp_get_wtime
+    // will be inaccurate but otherwise programs can still run.
+    if (auto Err = getDeviceAttrRaw(HSA_AMD_AGENT_INFO_TIMESTAMP_FREQUENCY,
+                                    ClockFrequency))
+      ClockFrequency = 0;
 
     // Load the grid values dependending on the wavefront.
     if (WavefrontSize == 32)

``````````

</details>


https://github.com/llvm/llvm-project/pull/70987