Use X64 ASM ed25519 signatures on Linux/x64, which are about 10X faster. Will matter a lot for network controllers, not so much for other things.

ext/ed25519-amd64-asm/fe25519_pack.c

@@ -0,0 +1,13 @@
+#include "fe25519.h"
+
+/* Assumes input x being reduced below 2^255 */
+void fe25519_pack(unsigned char r[32], const fe25519 *x)
+{
+  int i;
+  fe25519 t;
+  t = *x;
+  fe25519_freeze(&t);
+  /* assuming little-endian */
+  for(i=0;i<32;i++) r[i] = i[(unsigned char *)&t.v]; 
+}
+