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7401b26824
Before: Ten builds, laptop -j5, no ccache: ``` real 0m36.686000-38.956000(38.608+/-0.65)s user 2m32.864000-42.253000(40.7545+/-2.7)s sys 0m16.618000-18.316000(17.8531+/-0.48)s ``` Ten builds, laptop -j5, ccache (warm): ``` real 0m8.212000-8.577000(8.39989+/-0.13)s user 0m12.731000-13.212000(12.9751+/-0.17)s sys 0m3.697000-3.902000(3.83722+/-0.064)s ``` After: Ten builds, laptop -j5, no ccache: 8% faster ``` real 0m33.802000-35.773000(35.468+/-0.54)s user 2m19.073000-27.754000(26.2542+/-2.3)s sys 0m15.784000-17.173000(16.7165+/-0.37)s ``` Ten builds, laptop -j5, ccache (warm): 1% faster ``` real 0m8.200000-8.485000(8.30138+/-0.097)s user 0m12.485000-13.100000(12.7344+/-0.19)s sys 0m3.702000-3.889000(3.78787+/-0.056)s ``` Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
58 lines
1.1 KiB
C
58 lines
1.1 KiB
C
#include "pseudorand.h"
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#include <assert.h>
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#include <ccan/crypto/sha256/sha256.h>
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#include <ccan/crypto/siphash24/siphash24.h>
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#include <ccan/isaac/isaac64.h>
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#include <ccan/likely/likely.h>
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#include <sodium/randombytes.h>
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#include <string.h>
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static struct isaac64_ctx isaac64;
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static struct siphash_seed siphashseed;
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static bool pseudorand_initted = false;
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static void init_if_needed(void)
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{
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if (unlikely(!pseudorand_initted)) {
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unsigned char seedbuf[16];
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struct sha256 sha;
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randombytes_buf(seedbuf, sizeof(seedbuf));
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memcpy(&siphashseed, seedbuf, sizeof(siphashseed));
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/* In case isaac is reversible, don't leak seed. */
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sha256(&sha, seedbuf, sizeof(seedbuf));
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isaac64_init(&isaac64, sha.u.u8, sizeof(sha.u.u8));
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pseudorand_initted = true;
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}
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}
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uint64_t pseudorand(uint64_t max)
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{
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init_if_needed();
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assert(max);
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return isaac64_next_uint(&isaac64, max);
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}
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uint64_t pseudorand_u64(void)
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{
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init_if_needed();
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return isaac64_next_uint64(&isaac64);
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}
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double pseudorand_double(void)
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{
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init_if_needed();
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return isaac64_next_double(&isaac64);
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}
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const struct siphash_seed *siphash_seed(void)
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{
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init_if_needed();
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return &siphashseed;
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}
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