[Quant] make x86 the default quantization backend (qengine)

Xia-Weiwen · Xia-Weiwen · commit f529bbe11246 · 2022-12-21T15:15:20.000+08:00
diff --git a/aten/src/ATen/Context.cpp b/aten/src/ATen/Context.cpp
@@ -307,7 +307,12 @@ at::QEngine Context::qEngine() const {
 
 #ifdef USE_FBGEMM
     if (fbgemm::fbgemmSupportedCPU()) {
-      qengine = at::kFBGEMM;
+      /* X86 is enabled if and only if fbgemm is available.
+       * It combines goodness of fbgemm and onednn by dispatching.
+       * If onednn not available, always dispatch to fbgemm.
+       * Make it default qengine for X86 CPU platforms.
+      */
+      qengine = at::kX86;
     }
 #endif
     return qengine;
