diff --git a/src/crystal/event_loop/epoll.cr b/src/crystal/event_loop/epoll.cr
index 2d7d08ce7c94..371b9039b6b5 100644
--- a/src/crystal/event_loop/epoll.cr
+++ b/src/crystal/event_loop/epoll.cr
@@ -55,7 +55,7 @@ class Crystal::EventLoop::Epoll < Crystal::EventLoop::Polling
   {% end %}
 
   private def system_run(blocking : Bool, & : Fiber ->) : Nil
-    Crystal.trace :evloop, "run", blocking: blocking ? 1 : 0
+    Crystal.trace :evloop, "run", blocking: blocking
 
     # wait for events (indefinitely when blocking)
     buffer = uninitialized LibC::EpollEvent[128]
diff --git a/src/crystal/event_loop/kqueue.cr b/src/crystal/event_loop/kqueue.cr
index 52a7701ef2b1..47f00ddc9e89 100644
--- a/src/crystal/event_loop/kqueue.cr
+++ b/src/crystal/event_loop/kqueue.cr
@@ -73,7 +73,7 @@ class Crystal::EventLoop::Kqueue < Crystal::EventLoop::Polling
   private def system_run(blocking : Bool, & : Fiber ->) : Nil
     buffer = uninitialized LibC::Kevent[128]
 
-    Crystal.trace :evloop, "run", blocking: blocking ? 1 : 0
+    Crystal.trace :evloop, "run", blocking: blocking
     timeout = blocking ? nil : Time::Span.zero
     kevents = @kqueue.wait(buffer.to_slice, timeout)
 
diff --git a/src/crystal/scheduler.cr b/src/crystal/scheduler.cr
index ad0f2a55672e..efee6b3c06f1 100644
--- a/src/crystal/scheduler.cr
+++ b/src/crystal/scheduler.cr
@@ -66,7 +66,7 @@ class Crystal::Scheduler
   end
 
   def self.sleep(time : Time::Span) : Nil
-    Crystal.trace :sched, "sleep", for: time.total_nanoseconds.to_i64!
+    Crystal.trace :sched, "sleep", for: time
     Thread.current.scheduler.sleep(time)
   end
 
@@ -225,7 +225,7 @@ class Crystal::Scheduler
       pending = Atomic(Int32).new(count - 1)
       @@workers = Array(Thread).new(count) do |i|
         if i == 0
-          worker_loop = Fiber.new(name: "Worker Loop") { Thread.current.scheduler.run_loop }
+          worker_loop = Fiber.new(name: "worker-loop") { Thread.current.scheduler.run_loop }
           worker_loop.set_current_thread
           Thread.current.scheduler.enqueue worker_loop
           Thread.current
@@ -272,7 +272,7 @@ class Crystal::Scheduler
 
   # Background loop to cleanup unused fiber stacks.
   def spawn_stack_pool_collector
-    fiber = Fiber.new(name: "Stack pool collector", &->@stack_pool.collect_loop)
+    fiber = Fiber.new(name: "stack-pool-collector", &->@stack_pool.collect_loop)
     {% if flag?(:preview_mt) %} fiber.set_current_thread {% end %}
     enqueue(fiber)
   end
diff --git a/src/crystal/system/unix/signal.cr b/src/crystal/system/unix/signal.cr
index 802cb418db15..a68108ad327a 100644
--- a/src/crystal/system/unix/signal.cr
+++ b/src/crystal/system/unix/signal.cr
@@ -82,7 +82,7 @@ module Crystal::System::Signal
   end
 
   private def self.start_loop
-    spawn(name: "Signal Loop") do
+    spawn(name: "signal-loop") do
       loop do
         value = reader.read_bytes(Int32)
       rescue IO::Error
diff --git a/src/crystal/system/win32/process.cr b/src/crystal/system/win32/process.cr
index 5eb02d826c3b..5249491bbd3f 100644
--- a/src/crystal/system/win32/process.cr
+++ b/src/crystal/system/win32/process.cr
@@ -203,7 +203,7 @@ struct Crystal::System::Process
   def self.start_interrupt_loop : Nil
     return unless @@setup_interrupt_handler.test_and_set
 
-    spawn(name: "Interrupt signal loop") do
+    spawn(name: "interrupt-signal-loop") do
       while true
         @@interrupt_count.wait { sleep 50.milliseconds }
 
diff --git a/src/crystal/tracing.cr b/src/crystal/tracing.cr
index 684680b10b28..d9508eda85a8 100644
--- a/src/crystal/tracing.cr
+++ b/src/crystal/tracing.cr
@@ -51,37 +51,58 @@ module Crystal
           @size = 0
         end
 
-        def write(bytes : Bytes) : Nil
+        def write(value : Bytes) : Nil
           pos = @size
           remaining = N - pos
           return if remaining == 0
 
-          n = bytes.size.clamp(..remaining)
-          bytes.to_unsafe.copy_to(@buf.to_unsafe + pos, n)
+          n = value.size.clamp(..remaining)
+          value.to_unsafe.copy_to(@buf.to_unsafe + pos, n)
           @size = pos + n
         end
 
-        def write(string : String) : Nil
-          write string.to_slice
+        def write(value : String) : Nil
+          write value.to_slice
         end
 
-        def write(fiber : Fiber) : Nil
-          write fiber.as(Void*)
-          write ":"
-          write fiber.name || "?"
+        def write(value : Char) : Nil
+          chars = uninitialized UInt8[4]
+          i = 0
+          value.each_byte do |byte|
+            chars[i] = byte
+            i += 1
+          end
+          write chars.to_slice[0, i]
+        end
+
+        def write(value : Fiber) : Nil
+          write value.as(Void*)
+          write ':'
+          write value.name || '?'
         end
 
-        def write(ptr : Pointer) : Nil
+        def write(value : Pointer) : Nil
           write "0x"
-          System.to_int_slice(ptr.address, 16, true, 2) { |bytes| write(bytes) }
+          System.to_int_slice(value.address, 16, true, 2) { |bytes| write(bytes) }
+        end
+
+        def write(value : Int::Signed) : Nil
+          System.to_int_slice(value, 10, true, 2) { |bytes| write(bytes) }
+        end
+
+        def write(value : Int::Unsigned) : Nil
+          System.to_int_slice(value, 10, false, 2) { |bytes| write(bytes) }
+        end
+
+        def write(value : Time::Span) : Nil
+          write(value.seconds * Time::NANOSECONDS_PER_SECOND + value.nanoseconds)
         end
 
-        def write(int : Int::Signed) : Nil
-          System.to_int_slice(int, 10, true, 2) { |bytes| write(bytes) }
+        def write(value : Bool) : Nil
+          write value ? '1' : '0'
         end
 
-        def write(uint : Int::Unsigned) : Nil
-          System.to_int_slice(uint, 10, false, 2) { |bytes| write(bytes) }
+        def write(value : Nil) : Nil
         end
 
         def to_slice : Bytes