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mdbx: add mdbx_osal_jitter() and mdbx_jitter4testing().

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This commit is contained in:
Leo Yuriev
2017-04-27 15:18:33 +03:00
parent 40dee6f05f
commit 7204c46421
4 changed files with 36 additions and 13 deletions
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26
src/osal.c
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@@ -626,3 +626,29 @@ int mdbx_mlock(const void *address, size_t length) {
return (mlock(address, length) == 0) ? MDB_SUCCESS : errno;
#endif
}
/*----------------------------------------------------------------------------*/
__cold void mdbx_osal_jitter(bool tiny) {
for (;;) {
#if defined(_M_IX86) || defined(_M_X64) || defined(__i386__) || \
defined(__x86_64__)
const unsigned salt = 277u * (unsigned)__rdtsc();
#else
const unsigned salt = rand();
#endif
const unsigned coin = salt % (tiny ? 29u : 43u);
if (coin < 43 / 3)
break;
#if defined(_WIN32) || defined(_WIN64)
SwitchToThread();
if (coin > 43 * 2 / 3)
Sleep(1);
#else
sched_yield();
if (coin > 43 * 2 / 3)
usleep(coin);
#endif
}
}