Thanks, but this is now not thread-safe. I'm not sure how much we should
care about that, but anyway, as I see it there are three options:
1) Add some kind of locking.
2) Make the caller provide a struct for the state (similar to rand_r).
3) Ignore the issue and add a fat warning comment about it.
Personally, I'd say (2) is the most robust option.
Cheers,
Nicolai
On 21.03.2017 09:57, Timothy Arceri wrote:
---
src/gallium/drivers/radeon/r600_test_dma.c | 3 +-
src/util/rand_xor.c | 62 ++++++++++++++++++++++++++++--
src/util/rand_xor.h | 6 ++-
3 files changed, 64 insertions(+), 7 deletions(-)
diff --git a/src/gallium/drivers/radeon/r600_test_dma.c
b/src/gallium/drivers/radeon/r600_test_dma.c
index 7d636b9..abef8ed 100644
--- a/src/gallium/drivers/radeon/r600_test_dma.c
+++ b/src/gallium/drivers/radeon/r600_test_dma.c
@@ -172,22 +172,21 @@ void r600_test_dma(struct r600_common_screen *rscreen)
max_levels = screen->get_param(screen, PIPE_CAP_MAX_TEXTURE_2D_LEVELS);
max_tex_side = 1 << (max_levels - 1);
/* Max 128 MB allowed for both textures. */
max_alloc_size = 128 * 1024 * 1024;
/* the seed for random test parameters */
srand(0x9b47d95b);
/* the seed for random pixel data */
- seed_xorshift128plus[0] = 0x3bffb83978e24f88;
- seed_xorshift128plus[1] = 0x9238d5d56c71cd35;
+ s_rand_xorshift128plus(false);
iterations = 1000000000; /* just kill it when you are bored */
num_partial_copies = 30;
/* These parameters are randomly generated per test:
* - whether to do one whole-surface copy or N partial copies per test
* - which tiling modes to use (LINEAR_ALIGNED, 1D, 2D)
* - which texture dimensions to use
* - whether to use VRAM (all tiling modes) and GTT (staging, linear
* only) allocations
diff --git a/src/util/rand_xor.c b/src/util/rand_xor.c
index adb799d..cc834fa 100644
--- a/src/util/rand_xor.c
+++ b/src/util/rand_xor.c
@@ -1,21 +1,77 @@
-/* Super fast random number generator.
+/*
+ * Copyright 2017 Timothy Arceri
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
THE
+ * SOFTWARE.
*
- * This rand_xorshift128plus function by Sebastiano Vigna belongs
- * to the public domain.
*/
+#if defined(__linux__)
+#include <sys/file.h>
+#include <unistd.h>
+#endif
+
#include "rand_xor.h"
+static uint64_t seed_xorshift128plus[2];
+
+/* Super fast random number generator.
+ *
+ * This rand_xorshift128plus function by Sebastiano Vigna belongs
+ * to the public domain.
+ */
uint64_t
rand_xorshift128plus(void)
{
uint64_t *s = seed_xorshift128plus;
uint64_t s1 = s[0];
const uint64_t s0 = s[1];
s[0] = s0;
s1 ^= s1 << 23;
s[1] = s1 ^ s0 ^ (s1 >> 18) ^ (s0 >> 5);
return s[1] + s0;
}
+
+void
+s_rand_xorshift128plus(bool randomised_seed)
+{
+#if defined(__linux__)
+ if (!randomised_seed)
+ goto fixed_seed;
+
+ int fd = open("/dev/urandom", O_RDONLY);
+ if (fd < 0)
+ goto fixed_seed;
+
+ size_t seed_size = sizeof(uint64_t) * 2;
+ if (read(fd, &seed_xorshift128plus, seed_size) != seed_size)
+ goto fixed_seed;
+
+ close(fd);
+ return;
+
+fixed_seed:
+#endif
+
+ /* Fallback to a fixed seed */
+ seed_xorshift128plus[0] = 0x3bffb83978e24f88;
+ seed_xorshift128plus[1] = 0x9238d5d56c71cd35;
+}
diff --git a/src/util/rand_xor.h b/src/util/rand_xor.h
index c7667e4..8a48d63 100644
--- a/src/util/rand_xor.h
+++ b/src/util/rand_xor.h
@@ -19,17 +19,19 @@
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
THE
* SOFTWARE.
*
*/
#ifndef RAND_XOR_H
#define RAND_XOR_H
#include <stdint.h>
-
-static uint64_t seed_xorshift128plus[2];
+#include <stdbool.h>
uint64_t
rand_xorshift128plus(void);
+void
+s_rand_xorshift128plus(bool randomised_seed);
+
#endif /* RAND_XOR_H */
_______________________________________________
mesa-dev mailing list
mesa-dev@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/mesa-dev
