add functions without overflow

3 files changed, 31 insertions, 0 deletions

diff --git a/util/datetime/cputimer.cpp b/util/datetime/cputimer.cpp
index a032dbd3df..32ccfd4740 100644
--- a/util/datetime/cputimer.cpp
+++ b/util/datetime/cputimer.cpp
@@ -49,10 +49,27 @@ TDuration CyclesToDuration(ui64 cycles) {
     return TDuration::MicroSeconds(cycles * 1000000 / GetCyclesPerSecond());
 }
 
+TDuration CyclesToDurationSafe(ui64 cycles)
+{
+    constexpr ui64 cyclesLimit = std::numeric_limits<ui64>::max() / 1000000;
+    if (cycles <= cyclesLimit) {
+        return CyclesToDuration(cycles);
+    }
+    return TDuration::MicroSeconds(cycles / GetCyclesPerSecond() * 1000000);
+}
+
 ui64 DurationToCycles(TDuration duration) {
     return duration.MicroSeconds() * GetCyclesPerSecond() / 1000000;
 }
 
+ui64 DurationToCyclesSafe(TDuration duration)
+{
+    if (duration.MicroSeconds() <= std::numeric_limits<ui64>::max() / GetCyclesPerSecond()) {
+        return DurationToCycles(duration);
+    }
+    return duration.MicroSeconds() / 1000000 * GetCyclesPerSecond();
+}
+
 TPrecisionTimer::TPrecisionTimer()
     : Start(::GetCycleCount())
 {
diff --git a/util/datetime/cputimer.h b/util/datetime/cputimer.h
index 7d38d5bdb3..b24d6fae8e 100644
--- a/util/datetime/cputimer.h
+++ b/util/datetime/cputimer.h
@@ -62,6 +62,10 @@ void SetCyclesPerSecond(ui64 cycles);
 TDuration CyclesToDuration(ui64 cycles);
 ui64 DurationToCycles(TDuration duration);
 
+// NBS-3400 - CyclesToDuration and DurationToCycles may overflow for long running events
+TDuration CyclesToDurationSafe(ui64 cycles);
+ui64 DurationToCyclesSafe(TDuration duration);
+
 class TPrecisionTimer {
 private:
     ui64 Start = 0;
diff --git a/util/datetime/cputimer_ut.cpp b/util/datetime/cputimer_ut.cpp
new file mode 100644
index 0000000000..21a657d5c7
--- /dev/null
+++ b/util/datetime/cputimer_ut.cpp
@@ -0,0 +1,10 @@
+#include <library/cpp/testing/unittest/registar.h>
+
+#include "cputimer.h"
+
+Y_UNIT_TEST_SUITE(TestCpuTimerSuite) {
+    Y_UNIT_TEST(TestCyclesToDurationSafe) {
+        ui64 cycles = DurationToCyclesSafe(TDuration::Hours(24));
+        UNIT_ASSERT_VALUES_EQUAL(24, CyclesToDurationSafe(cycles).Hours());
+    }
+}