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Chaos sanitizer: development

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This commit is contained in:
Alexey Milovidov 2020-03-01 19:07:51 +03:00
parent 2c6d1eebf2
commit e00767134f
1 changed files with 1 additions and 9 deletions
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10
dbms/src/Common/tests/chaos_sanitizer.cpp
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@ -109,16 +109,8 @@ private:
static constexpr UInt32 TIMER_PRECISION = 1e6;
/// Randomize offset as uniform random value from 0 to period - 1.
/// It will allow to sample short queries even if timer period is large.
/// (For example, with period of 1 second, query with 50 ms duration will be sampled with 1 / 20 probability).
/// It also helps to avoid interference (moire).
UInt32 period_rand = std::uniform_int_distribution<UInt32>(0, cpu_time_period_us)(thread_local_rng);
struct timeval interval{.tv_sec = long(cpu_time_period_us / TIMER_PRECISION), .tv_usec = long(cpu_time_period_us % TIMER_PRECISION)};
struct timeval offset{.tv_sec = period_rand / TIMER_PRECISION, .tv_usec = period_rand % TIMER_PRECISION};
struct itimerval timer = {.it_interval = interval, .it_value = offset};
struct itimerval timer = {.it_interval = interval, .it_value = {0, 0}};
if (0 != setitimer(ITIMER_PROF, &timer, nullptr))
throwFromErrno("Failed to create profiling timer", ErrorCodes::CANNOT_CREATE_TIMER);