diff --git a/server/TracyEvent.hpp b/server/TracyEvent.hpp
index 25b3ef3c..708e5662 100644
--- a/server/TracyEvent.hpp
+++ b/server/TracyEvent.hpp
@@ -131,6 +131,11 @@ public:
         return val;
     }
 
+    tracy_force_inline bool IsNonNegative() const
+    {
+        return ( m_val[5] >> 7 ) == 0;
+    }
+
 private:
     uint8_t m_val[6];
 };
@@ -355,6 +360,7 @@ struct ContextSwitchData
     tracy_force_inline void SetStart( int64_t start ) { assert( start < (int64_t)( 1ull << 47 ) ); memcpy( ((char*)&_start_cpu)+2, &start, 4 ); memcpy( ((char*)&_start_cpu)+6, ((char*)&start)+4, 2 ); }
     tracy_force_inline int64_t End() const { return int64_t( _end_reason_state ) >> 16; }
     tracy_force_inline void SetEnd( int64_t end ) { assert( end < (int64_t)( 1ull << 47 ) ); memcpy( ((char*)&_end_reason_state)+2, &end, 4 ); memcpy( ((char*)&_end_reason_state)+6, ((char*)&end)+4, 2 ); }
+    tracy_force_inline bool IsEndValid() const { return ( _end_reason_state >> 63 ) == 0; }
     tracy_force_inline uint8_t Cpu() const { return uint8_t( _start_cpu & 0xFF ); }
     tracy_force_inline void SetCpu( uint8_t cpu ) { memcpy( &_start_cpu, &cpu, 1 ); }
     tracy_force_inline int8_t Reason() const { return int8_t( (_end_reason_state >> 8) & 0xFF ); }
@@ -378,6 +384,7 @@ struct ContextSwitchCpu
     tracy_force_inline void SetStart( int64_t start ) { assert( start < (int64_t)( 1ull << 47 ) ); memcpy( ((char*)&_start_thread)+2, &start, 4 ); memcpy( ((char*)&_start_thread)+6, ((char*)&start)+4, 2 ); }
     tracy_force_inline int64_t End() const { return _end.Val(); }
     tracy_force_inline void SetEnd( int64_t end ) { assert( end < (int64_t)( 1ull << 47 ) ); _end.SetVal( end ); }
+    tracy_force_inline bool IsEndValid() const { return _end.IsNonNegative(); }
     tracy_force_inline uint16_t Thread() const { return uint16_t( _start_thread ); }
     tracy_force_inline void SetThread( uint16_t thread ) { memcpy( &_start_thread, &thread, 2 ); }
 
diff --git a/server/TracyView.cpp b/server/TracyView.cpp
index 38fb9afd..98e98324 100644
--- a/server/TracyView.cpp
+++ b/server/TracyView.cpp
@@ -2664,7 +2664,7 @@ void View::DrawZones()
                 {
                     const auto& back = ctx->v.back();
                     first = ctx->v.begin()->Start();
-                    last = back.End() >= 0 ? back.End() : back.Start();
+                    last = back.IsEndValid() ? back.End() : back.Start();
                 }
                 if( !v->timeline.empty() )
                 {
@@ -3095,7 +3095,7 @@ void View::DrawContextSwitches( const ContextSwitch* ctx, bool hover, double pxn
             }
         }
 
-        const auto end = ev.End() >= 0 ? ev.End() : m_worker.GetLastTime();
+        const auto end = ev.IsEndValid() ? ev.End() : m_worker.GetLastTime();
         const auto zsz = std::max( ( end - ev.Start() ) * pxns, pxns * 0.5 );
         if( zsz < MinCtxSize )
         {
@@ -3111,7 +3111,7 @@ void View::DrawContextSwitches( const ContextSwitch* ctx, bool hover, double pxn
                 if( it == prevIt ) ++it;
                 num += std::distance( prevIt, it );
                 if( it == citend ) break;
-                const auto nend = it->End() >= 0 ? it->End() : m_worker.GetLastTime();
+                const auto nend = it->IsEndValid() ? it->End() : m_worker.GetLastTime();
                 const auto pxnext = ( nend - m_vd.zvStart ) * pxns;
                 if( pxnext - px1 >= MinCtxSize * 2 ) break;
                 px1 = pxnext;
@@ -4718,7 +4718,7 @@ int View::DrawCpuData( int offset, double pxns, const ImVec2& wpos, bool hover,
                                     if( it == prevIt ) ++it;
                                     num += std::distance( prevIt, it );
                                     if( it == eit ) break;
-                                    const auto nend = it->End() >= 0 ? it->End() : m_worker.GetLastTime();
+                                    const auto nend = it->IsEndValid() ? it->End() : m_worker.GetLastTime();
                                     const auto pxnext = ( nend - m_vd.zvStart ) * pxns;
                                     if( pxnext - px1 >= MinVisSize * 2 ) break;
                                     px1 = pxnext;
diff --git a/server/TracyWorker.cpp b/server/TracyWorker.cpp
index 2adb0972..c32efb1c 100644
--- a/server/TracyWorker.cpp
+++ b/server/TracyWorker.cpp
@@ -1779,7 +1779,7 @@ void Worker::GetCpuUsageAtTime( int64_t time, int& own, int& other ) const
         if( !cs.empty() )
         {
             auto it = std::lower_bound( cs.begin(), cs.end(), time, [] ( const auto& l, const auto& r ) { return (uint64_t)l.End() < (uint64_t)r; } );
-            if( it != cs.end() && it->Start() <= time && it->End() >= 0 )
+            if( it != cs.end() && it->Start() <= time && it->IsEndValid() )
             {
                 if( GetPidFromTid( DecompressThreadExternal( it->Thread() ) ) == m_pid )
                 {
@@ -4766,7 +4766,7 @@ void Worker::ProcessThreadWakeup( const QueueThreadWakeup& ev )
         it = m_data.ctxSwitch.emplace( ev.thread, ctx ).first;
     }
     auto& data = it->second->v;
-    if( !data.empty() && data.back().End() < 0 ) return;        // wakeup of a running thread
+    if( !data.empty() && !data.back().IsEndValid() ) return;        // wakeup of a running thread
     auto& item = data.push_next();
     item.SetWakeup( time );
     item.SetStart( time );
@@ -4989,7 +4989,7 @@ void Worker::ReconstructContextSwitchUsage()
                         other++;
                         assert( other <= cpucnt );
                     }
-                    if( cpus[i].it->End() < 0 )
+                    if( !cpus[i].it->IsEndValid() )
                     {
                         cpus[i].it++;
                         assert( cpus[i].it = cpus[i].end );