Add benchmark for ECDH multiplication

Author: apoelstra

.gitignore

@@ -1,4 +1,5 @@
 bench_inv
+bench_ecdh
 bench_sign
 bench_verify
 bench_recover

Makefile.am

@@ -51,7 +51,7 @@ libsecp256k1_la_LIBADD = $(SECP_LIBS)
 
 noinst_PROGRAMS =
 if USE_BENCHMARK
-noinst_PROGRAMS += bench_verify bench_recover bench_sign bench_internal
+noinst_PROGRAMS += bench_verify bench_recover bench_sign bench_internal bench_ecdh
 bench_verify_SOURCES = src/bench_verify.c
 bench_verify_LDADD = libsecp256k1.la $(SECP_LIBS)
 bench_verify_LDFLAGS = -static
@@ -65,6 +65,10 @@ bench_internal_SOURCES = src/bench_internal.c
 bench_internal_LDADD = $(SECP_LIBS)
 bench_internal_LDFLAGS = -static
 bench_internal_CPPFLAGS = $(SECP_INCLUDES)
+bench_ecdh_SOURCES = src/bench_ecdh.c
+bench_ecdh_LDADD = libsecp256k1.la $(SECP_LIBS)
+bench_ecdh_LDFLAGS = -static
+bench_ecdh_CPPFLAGS = $(SECP_INCLUDES)
 endif
 
 if USE_TESTS

src/bench_ecdh.c

@@ -0,0 +1,49 @@
+/**********************************************************************
+ * Copyright (c) 2015 Pieter Wuille, Andrew Poelstra                  *
+ * Distributed under the MIT software license, see the accompanying   *
+ * file COPYING or http://www.opensource.org/licenses/mit-license.php.*
+ **********************************************************************/
+
+#include <string.h>
+
+#include "include/secp256k1.h"
+#include "util.h"
+#include "bench.h"
+
+typedef struct {
+    unsigned char point[33];
+    int pointlen;
+    unsigned char scalar[32];
+} bench_multiply_t;
+
+static void bench_multiply_setup(void* arg) {
+    int i;
+    bench_multiply_t *data = (bench_multiply_t*)arg;
+    const unsigned char point[] = {
+        0x03,
+        0x54, 0x94, 0xc1, 0x5d, 0x32, 0x09, 0x97, 0x06,
+        0xc2, 0x39, 0x5f, 0x94, 0x34, 0x87, 0x45, 0xfd,
+        0x75, 0x7c, 0xe3, 0x0e, 0x4e, 0x8c, 0x90, 0xfb,
+        0xa2, 0xba, 0xd1, 0x84, 0xf8, 0x83, 0xc6, 0x9f
+    };
+
+    for (i = 0; i < 32; i++) data->scalar[i] = i + 1;
+    data->pointlen = sizeof(point);
+    memcpy(data->point, point, data->pointlen);
+}
+
+static void bench_multiply(void* arg) {
+    int i;
+    bench_multiply_t *data = (bench_multiply_t*)arg;
+
+    for (i = 0; i < 20000; i++) {
+        CHECK(secp256k1_point_multiply(data->point, &data->pointlen, data->scalar) == 1);
+    }
+}
+
+int main(void) {
+    bench_multiply_t data;
+
+    run_benchmark("ecdh_mult", bench_multiply, bench_multiply_setup, NULL, &data, 10, 20000);
+    return 0;
+}