Merge pull request #1538 from DataDog/ivoanjo/tweak-debug-message-abo…

…ut-missing-instrumentation

Tweak debug message about missing instrumentation

lib/ddtrace/profiling/collectors/stack.rb

@@ -224,6 +224,7 @@ def warn_about_missing_cpu_time_instrumentation(thread)
             #    In this case, the fix is to make sure ddtrace gets loaded before any other parts of the application.
             #
             # b) The thread was started using the Ruby native APIs (e.g. from a C extension such as ffi).
+            #    Known cases right now that trigger this are the ethon/typhoeus gems.
             #    We currently have no solution for this case; these threads will always be missing our CPU instrumentation.
             #
             # c) The thread was started with `Thread.start`/`Thread.fork` and hasn't yet enabled the instrumentation.
@@ -232,7 +233,9 @@ def warn_about_missing_cpu_time_instrumentation(thread)
             #    it to run and our instrumentation to be applied.
             #
             if thread_api.current.respond_to?(:cpu_time) && thread_api.current.cpu_time
-              Datadog.logger.debug("Detected thread ('#{thread}') with missing CPU profiling instrumentation.")
+              Datadog.logger.debug(
+                "Thread ('#{thread}') is missing profiling instrumentation; other threads should be unaffected"
+              )
             end
           end
         end

spec/ddtrace/profiling/collectors/stack_spec.rb

@@ -427,7 +427,7 @@
         it { is_expected.to be nil }
 
         it 'logs a warning' do
-          expect(Datadog.logger).to receive(:debug).with(/missing CPU profiling instrumentation/)
+          expect(Datadog.logger).to receive(:debug).with(/missing profiling instrumentation/)
 
           get_cpu_time_interval!
         end