@@ -226,7 +226,10 @@ LOCALES := \
include ../gen-locales.mk
endif
-stdlib-benchset := strtod
+stdlib-benchset := \
+ arc4random \
+ strtod \
+ # stdlib-benchset
stdio-common-benchset := sprintf
new file mode 100644
@@ -0,0 +1,224 @@
+/* arc4random benchmarks.
+ Copyright (C) 2022 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+
+ The GNU C Library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Lesser General Public
+ License as published by the Free Software Foundation; either
+ version 2.1 of the License, or (at your option) any later version.
+
+ The GNU C Library is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public
+ License along with the GNU C Library; if not, see
+ <https://www.gnu.org/licenses/>. */
+
+#include "bench-timing.h"
+#include "json-lib.h"
+#include <array_length.h>
+#include <intprops.h>
+#include <signal.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <support/support.h>
+#include <support/timespec.h>
+#include <support/xthread.h>
+
+/* Prevent compiler to optimize away call. */
+#define DO_NOT_OPTIMIZE(__value) \
+ ({ \
+ __typeof (__value) __v = (__value); \
+ asm volatile("" : : "r,m" (__v) : "memory");\
+ })
+
+static volatile sig_atomic_t timer_finished;
+
+static void timer_callback (int unused)
+{
+ timer_finished = 1;
+}
+
+static timer_t timer;
+
+/* Run for approximately DURATION seconds, and it does not matter who
+ receive the signal (so not need to mask it on main thread). */
+static void
+timer_start (void)
+{
+ timer_finished = 0;
+ timer = support_create_timer (DURATION, 0, false, timer_callback);
+}
+static void
+timer_stop (void)
+{
+ support_delete_timer (timer);
+}
+
+static const uint32_t sizes[] = { 0, 16, 32, 48, 64, 80, 96, 112, 128 };
+
+static double
+bench_throughput (void)
+{
+ uint64_t n = 0;
+
+ struct timespec start, end;
+ clock_gettime (CLOCK_MONOTONIC, &start);
+ while (1)
+ {
+ DO_NOT_OPTIMIZE (arc4random ());
+ n++;
+
+ if (timer_finished == 1)
+ break;
+ }
+ clock_gettime (CLOCK_MONOTONIC, &end);
+ struct timespec diff = timespec_sub (end, start);
+
+ double total = (double) n * sizeof (uint32_t);
+ double duration = (double) diff.tv_sec
+ + (double) diff.tv_nsec / TIMESPEC_HZ;
+
+ return total / duration;
+}
+
+static double
+bench_latency (void)
+{
+ timing_t start, stop, cur;
+ const size_t iters = 1024;
+
+ TIMING_NOW (start);
+ for (size_t i = 0; i < iters; i++)
+ DO_NOT_OPTIMIZE (arc4random ());
+ TIMING_NOW (stop);
+
+ TIMING_DIFF (cur, start, stop);
+
+ return (double) (cur) / (double) iters;
+}
+
+static double
+bench_buf_throughput (size_t len)
+{
+ uint8_t buf[len];
+ uint64_t n = 0;
+
+ struct timespec start, end;
+ clock_gettime (CLOCK_MONOTONIC, &start);
+ while (1)
+ {
+ arc4random_buf (buf, len);
+ n++;
+
+ if (timer_finished == 1)
+ break;
+ }
+ clock_gettime (CLOCK_MONOTONIC, &end);
+ struct timespec diff = timespec_sub (end, start);
+
+ double total = (double) n * len;
+ double duration = (double) diff.tv_sec
+ + (double) diff.tv_nsec / TIMESPEC_HZ;
+
+ return total / duration;
+}
+
+static double
+bench_buf_latency (size_t len)
+{
+ timing_t start, stop, cur;
+ const size_t iters = 1024;
+
+ uint8_t buf[len];
+
+ TIMING_NOW (start);
+ for (size_t i = 0; i < iters; i++)
+ arc4random_buf (buf, len);
+ TIMING_NOW (stop);
+
+ TIMING_DIFF (cur, start, stop);
+
+ return (double) (cur) / (double) iters;
+}
+
+static void
+bench_singlethread (json_ctx_t *json_ctx)
+{
+ json_element_object_begin (json_ctx);
+
+ json_array_begin (json_ctx, "throughput");
+ for (int i = 0; i < array_length (sizes); i++)
+ {
+ timer_start ();
+ double r = sizes[i] == 0
+ ? bench_throughput () : bench_buf_throughput (sizes[i]);
+ timer_stop ();
+
+ json_element_double (json_ctx, r);
+ }
+ json_array_end (json_ctx);
+
+ json_array_begin (json_ctx, "latency");
+ for (int i = 0; i < array_length (sizes); i++)
+ {
+ timer_start ();
+ double r = sizes[i] == 0
+ ? bench_latency () : bench_buf_latency (sizes[i]);
+ timer_stop ();
+
+ json_element_double (json_ctx, r);
+ }
+ json_array_end (json_ctx);
+
+ json_element_object_end (json_ctx);
+}
+
+static void
+run_bench (json_ctx_t *json_ctx, const char *name,
+ char *const*fnames, size_t fnameslen,
+ void (*bench)(json_ctx_t *ctx))
+{
+ json_attr_object_begin (json_ctx, name);
+ json_array_begin (json_ctx, "functions");
+ for (int i = 0; i < fnameslen; i++)
+ json_element_string (json_ctx, fnames[i]);
+ json_array_end (json_ctx);
+
+ json_array_begin (json_ctx, "results");
+ bench (json_ctx);
+ json_array_end (json_ctx);
+ json_attr_object_end (json_ctx);
+}
+
+static int
+do_test (void)
+{
+ char *fnames[array_length (sizes)];
+ for (int i = 0; i < array_length (sizes); i++)
+ if (sizes[i] == 0)
+ fnames[i] = xasprintf ("arc4random");
+ else
+ fnames[i] = xasprintf ("arc4random_buf(%u)", sizes[i]);
+
+ json_ctx_t json_ctx;
+ json_init (&json_ctx, 0, stdout);
+
+ json_document_begin (&json_ctx);
+ json_attr_string (&json_ctx, "timing_type", TIMING_TYPE);
+
+ run_bench (&json_ctx, "single-thread", fnames, array_length (fnames),
+ bench_singlethread);
+
+ json_document_end (&json_ctx);
+
+ for (int i = 0; i < array_length (sizes); i++)
+ free (fnames[i]);
+
+ return 0;
+}
+
+#include <support/test-driver.c>
@@ -25,9 +25,9 @@
#include <sys/param.h>
#include <sys/random.h>
-/* Besides the cipher state 'ctx', it keeps two counters: 'have' is the
- current valid bytes not yet consumed in 'buf', while 'count' is the maximum
- number of bytes until a reseed.
+/* arc4random keeps two counters: 'have' is the current valid bytes not yet
+ consumed in 'buf' while 'count' is the maximum number of bytes until a
+ reseed.
Both the initial seed and reseed try to obtain entropy from the kernel
and abort the process if none could be obtained.
@@ -81,10 +81,10 @@ arc4random_getrandom_failure (void)
__libc_fatal ("Fatal glibc error: Cannot get entropy for arc4random\n");
}
-/* Fork detection is done by checking if MADV_WIPEONFORK supported. If not
- the fork callback will reset the state on the fork call. It does not
- handle direct clone calls, nor vfork or _Fork (arc4random is not
- async-signal-safe due the internal lock usage). */
+/* If the kernel supports MADV_WIPEONFORK it is used to provide fork
+ detection. Otherwise, the state is resetied with an atfork handler. The
+ latter does not handle direct clone calls, nor vfork or _Fork (arc4random
+ is not async-signal-safe due to the internal lock usage). */
static void
arc4random_init (uint8_t *buf)
{