fix ya.make

1 files changed, 73 insertions, 0 deletions

diff --git a/library/cpp/yt/threading/spin_wait.cpp b/library/cpp/yt/threading/spin_wait.cpp
new file mode 100644
index 00000000000..309fdb8b3a4
--- /dev/null
+++ b/library/cpp/yt/threading/spin_wait.cpp
@@ -0,0 +1,73 @@
+#include "spin_wait.h"
+
+#include <util/datetime/base.h>
+
+#include <util/system/compiler.h>
+
+#include <atomic>
+
+namespace NYT::NThreading {
+
+////////////////////////////////////////////////////////////////////////////////
+
+static constexpr int SpinIterationCount = 1000;
+
+namespace {
+
+TDuration SuggestSleepDelay(int iteration)
+{
+    static std::atomic<ui64> Rand;
+    auto rand = Rand.load(std::memory_order_relaxed);
+    rand = 0x5deece66dLL * rand + 0xb;   // numbers from nrand48()
+    Rand.store(rand, std::memory_order_relaxed);
+
+    constexpr ui64 MinDelayUs = 128;
+
+    // Double delay every 8 iterations, up to 16x (2ms).
+    if (iteration > 32) {
+        iteration = 32;
+    }
+    ui64 delayUs = MinDelayUs << (iteration / 8);
+
+    // Randomize in delay..2*delay range, for resulting 128us..4ms range.
+    delayUs = delayUs | ((delayUs - 1) & rand);
+    return TDuration::MicroSeconds(delayUs);
+}
+
+} // namespace
+
+////////////////////////////////////////////////////////////////////////////////
+
+TSpinWait::TSpinWait(
+    const TSourceLocation& location,
+    ESpinLockActivityKind activityKind)
+    : Location_(location)
+    , ActivityKind_(activityKind)
+{ }
+
+TSpinWait::~TSpinWait()
+{
+    if (SlowPathStartInstant_ >= 0) {
+        auto cpuDelay = GetCpuInstant() - SlowPathStartInstant_;
+        InvokeSpinWaitSlowPathHooks(cpuDelay, Location_, ActivityKind_);
+    }
+}
+
+void TSpinWait::Wait()
+{
+    if (Y_LIKELY(SpinIteration_++ < SpinIterationCount)) {
+        return;
+    }
+
+    SpinIteration_ = 0;
+
+    if (SlowPathStartInstant_ < 0) {
+        SlowPathStartInstant_ = GetCpuInstant();
+    }
+
+    Sleep(SuggestSleepDelay(SleepIteration_++));
+}
+
+////////////////////////////////////////////////////////////////////////////////
+
+} // namespace NYT::NThreading