sycl : Add option to set the SYCL architecture for all targets (llama/10266)

* Add option to set the SYCL architecture for all targets
* Convert GGML_SYCL_HIP_TARGET to the more generic GGML_SYCL_ARCH option
* Document that setting GGML_SYCL_ARCH can improve the performance

ggml/CMakeLists.txt

@@ -164,6 +164,8 @@ option(GGML_SYCL                            "ggml: use SYCL"
 option(GGML_SYCL_F16                        "ggml: use 16 bit floats for sycl calculations"   OFF)
 set   (GGML_SYCL_TARGET "INTEL" CACHE STRING
                                             "ggml: sycl target device")
+set   (GGML_SYCL_DEVICE_ARCH "" CACHE STRING
+                                            "ggml: sycl device architecture")
 
 # extra artifacts
 option(GGML_BUILD_TESTS    "ggml: build tests"    ${GGML_STANDALONE})

ggml/src/ggml-sycl/CMakeLists.txt

@@ -72,10 +72,14 @@ else()
         set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -fsycl-targets=nvptx64-nvidia-cuda")
         target_link_libraries(ggml-sycl PRIVATE sycl pthread m dl onemkl)
     elseif (GGML_SYCL_TARGET STREQUAL "AMD")
-        if (GGML_SYCL_HIP_TARGET STREQUAL "")
-            message(ERROR "Can't enable SYCL hip backend, GGML_SYCL_HIP_TARGET has not been set.")
+        if (NOT GGML_SYCL_DEVICE_ARCH)
+            message(ERROR "Can't enable SYCL hip backend, GGML_SYCL_DEVICE_ARCH has not been set.")
         endif()
-        set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -fsycl-targets=amdgcn-amd-amdhsa -Xsycl-target-backend --offload-arch=${GGML_SYCL_HIP_TARGET}")
+        set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -fsycl-targets=amdgcn-amd-amdhsa")
         target_link_libraries(ggml-sycl PRIVATE sycl pthread m dl onemkl)
     endif()
+
+    if (GGML_SYCL_DEVICE_ARCH)
+      set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Xsycl-target-backend --offload-arch=${GGML_SYCL_DEVICE_ARCH}")
+  endif()
 endif()