diff --git a/auto/os/conf b/auto/os/conf
index d7f6e0382..bb0ce4ef2 100644
--- a/auto/os/conf
+++ b/auto/os/conf
@@ -115,6 +115,21 @@ case "$NGX_MACHINE" in
         NGX_MACH_CACHE_LINE=64
     ;;
 
+    ppc64* | powerpc64*)
+        have=NGX_ALIGNMENT value=16 . auto/define
+        NGX_MACH_CACHE_LINE=128
+    ;;
+
+    riscv64)
+        have=NGX_ALIGNMENT value=16 . auto/define
+        NGX_MACH_CACHE_LINE=64
+    ;;
+
+    s390x)
+        have=NGX_ALIGNMENT value=16 . auto/define
+        NGX_MACH_CACHE_LINE=256
+    ;;
+
     *)
         have=NGX_ALIGNMENT value=16 . auto/define
         NGX_MACH_CACHE_LINE=32