Add flag for optimising for specific CPU (#240)

CMakeLists.txt

@@ -5,6 +5,8 @@ option(FAABRIC_WASM_BUILD "Build Faabric wasm library" OFF)
 option(FAABRIC_BUILD_TESTS "Build Faabric tests" ON)
 option(FAABRIC_SELF_TRACING "Turn on system tracing using the logger" OFF)
 
+option(FAABRIC_TARGET_CPU "CPU to optimise for, e.g. skylake, icelake or native" OFF)
+
 # Enable colorized compiler output
 if("${CMAKE_CXX_COMPILER_ID}" STREQUAL "GNU")
     add_compile_options(-fdiagnostics-color=always)
@@ -13,7 +15,12 @@ elseif("${CMAKE_CXX_COMPILER_ID}" STREQUAL "Clang")
 endif()
 
 # Optimise for CPU
-include(cmake/OptimiseCPU.cmake)
+if(FAABRIC_TARGET_CPU)
+    message(STATUS "Optimising Faabric for CPU ${FAABRIC_TARGET_CPU}")
+    add_compile_options(-march=${FAABRIC_TARGET_CPU} -mtune=${FAABRIC_TARGET_CPU})
+else()
+    message(STATUS "Faabric not optimised for specific CPU")
+endif()
 
 # Top-level CMake config
 set(CMAKE_CXX_FLAGS "-Wall")

tasks/dev.py

@@ -15,7 +15,13 @@
 
 @task
 def cmake(
-    ctx, clean=False, shared=False, build="Debug", sanitiser="None", prof=False
+    ctx,
+    clean=False,
+    shared=False,
+    build="Debug",
+    sanitiser="None",
+    prof=False,
+    cpu=None,
 ):
     """
     Configures the build
@@ -44,6 +50,7 @@ def cmake(
         "-DCMAKE_C_COMPILER=/usr/bin/clang-13",
         "-DFAABRIC_USE_SANITISER={}".format(sanitiser),
         "-DFAABRIC_SELF_TRACING=ON" if prof else "",
+        "-DFAABRIC_TARGET_CPU={}".format(cpu) if cpu else "",
         PROJ_ROOT,
     ]