Initial code.

src/lib/scryptenc/scryptenc_cpuperf.c

Index: src/lib/scryptenc/scryptenc_cpuperf.c
diff --git a/src/lib/scryptenc/scryptenc_cpuperf.c b/src/lib/scryptenc/scryptenc_cpuperf.c
new file mode 100644
index 0000000000000000000000000000000000000000..aa2d5035d7f8e6b721a9b72394febef4cab0f256
--- /dev/null
+++ b/src/lib/scryptenc/scryptenc_cpuperf.c
@@ -0,0 +1,185 @@
+/*-
+ * Copyright 2009 Colin Percival
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ * This file was originally written by Colin Percival as part of the Tarsnap
+ * online backup system.
+ */
+#include "scrypt_platform.h"
+
+#include <sys/time.h>
+
+#include <stdint.h>
+#include <stdio.h>
+#include <time.h>
+
+#include "crypto_scrypt.h"
+
+#include "scryptenc_cpuperf.h"
+
+#ifdef HAVE_CLOCK_GETTIME
+
+static clock_t clocktouse;
+
+static int
+getclockres(double * resd)
+{
+	struct timespec res;
+
+	/*
+	 * Try clocks in order of preference until we find one which works.
+	 * (We assume that if clock_getres works, clock_gettime will, too.)
+	 * The use of if/else/if/else/if/else rather than if/elif/elif/else
+	 * is ugly but legal, and allows us to #ifdef things appropriately.
+	 */
+#ifdef CLOCK_VIRTUAL
+	if (clock_getres(CLOCK_VIRTUAL, &res) == 0)
+		clocktouse = CLOCK_VIRTUAL;
+	else
+#endif
+#ifdef CLOCK_MONOTONIC
+	if (clock_getres(CLOCK_MONOTONIC, &res) == 0)
+		clocktouse = CLOCK_MONOTONIC;
+	else
+#endif
+	if (clock_getres(CLOCK_REALTIME, &res) == 0)
+		clocktouse = CLOCK_REALTIME;
+	else
+		return (-1);
+
+	/* Convert clock resolution to a double. */
+	*resd = res.tv_sec + res.tv_nsec * 0.000000001;
+
+	return (0);
+}
+
+static int
+getclocktime(struct timespec * ts)
+{
+
+	if (clock_gettime(clocktouse, ts))
+		return (-1);
+
+	return (0);
+}
+
+#else
+static int
+getclockres(double * resd)
+{
+
+	*resd = 1.0 / CLOCKS_PER_SEC;
+
+	return (0);
+}
+
+static int
+getclocktime(struct timespec * ts)
+{
+	struct timeval tv;
+
+	if (gettimeofday(&tv, NULL))
+		return (-1);
+	ts->tv_sec = tv.tv_sec;
+	ts->tv_nsec = tv.tv_usec * 1000;
+
+	return (0);
+}
+#endif
+
+static int
+getclockdiff(struct timespec * st, double * diffd)
+{
+	struct timespec en;
+
+	if (getclocktime(&en))
+		return (1);
+	*diffd = (en.tv_nsec - st->tv_nsec) * 0.000000001 +
+	    (en.tv_sec - st->tv_sec);
+
+	return (0);
+}
+
+/**
+ * scryptenc_cpuperf(opps):
+ * Estimate the number of salsa20/8 cores which can be executed per second,
+ * and return the value via opps.
+ */
+int
+scryptenc_cpuperf(double * opps)
+{
+	struct timespec st;
+	double resd, diffd;
+	uint64_t i = 0;
+
+	/* Get the clock resolution. */
+	if (getclockres(&resd))
+		return (2);
+
+#ifdef DEBUG
+	fprintf(stderr, "Clock resolution is %f\n", resd);
+#endif
+
+	/* Loop until the clock ticks. */
+	if (getclocktime(&st))
+		return (2);
+	do {
+		/* Do an scrypt. */
+		if (crypto_scrypt(NULL, 0, NULL, 0, 16, 1, 1, NULL, 0))
+			return (3);
+
+		/* Has the clock ticked? */
+		if (getclockdiff(&st, &diffd))
+			return (2);
+		if (diffd > 0)
+			break;
+	} while (1);
+
+	/* Could how many scryps we can do before the next tick. */
+	if (getclocktime(&st))
+		return (2);
+	do {
+		/* Do an scrypt. */
+		if (crypto_scrypt(NULL, 0, NULL, 0, 128, 1, 1, NULL, 0))
+			return (3);
+
+		/* We invoked the salsa20/8 core 512 times. */
+		i += 512;
+
+		/* Check if we have looped for long enough. */
+		if (getclockdiff(&st, &diffd))
+			return (2);
+		if (diffd > resd)
+			break;
+	} while (1);
+
+#ifdef DEBUG
+	fprintf(stderr, "%ju salsa20/8 cores performed in %f seconds\n",
+	    (uintmax_t)i, diffd);
+#endif
+
+	/* We can do approximately i salsa20/8 cores per diffd seconds. */
+	*opps = i / diffd;
+	return (0);
+}