8238649: Call new Win32 API SetThreadDescription in os::set_native_thread_name

Co-authored-by: Markus GaisBauer <markus.gaisbauer@dynatrace.com>
Reviewed-by: stuefe, luhenry

src/hotspot/os/windows/os_windows.cpp

@@ -885,8 +885,62 @@ uint os::processor_id() {
   return (uint)GetCurrentProcessorNumber();
 }
 
+// For dynamic lookup of SetThreadDescription API
+typedef HRESULT (WINAPI *SetThreadDescriptionFnPtr)(HANDLE, PCWSTR);
+typedef HRESULT (WINAPI *GetThreadDescriptionFnPtr)(HANDLE, PWSTR*);
+static SetThreadDescriptionFnPtr _SetThreadDescription = NULL;
+DEBUG_ONLY(static GetThreadDescriptionFnPtr _GetThreadDescription = NULL;)
+
+// forward decl.
+errno_t convert_to_unicode(char const* char_path, LPWSTR* unicode_path);
+
 void os::set_native_thread_name(const char *name) {
 
+  // From Windows 10 and Windows 2016 server, we have a direct API
+  // for setting the thread name/description:
+  // https://docs.microsoft.com/en-us/windows/win32/api/processthreadsapi/nf-processthreadsapi-setthreaddescription
+
+  if (_SetThreadDescription != NULL) {
+    // SetThreadDescription takes a PCWSTR but we have conversion routines that produce
+    // LPWSTR. The only difference is that PCWSTR is a pointer to const WCHAR.
+    LPWSTR unicode_name;
+    errno_t err = convert_to_unicode(name, &unicode_name);
+    if (err == ERROR_SUCCESS) {
+      HANDLE current = GetCurrentThread();
+      HRESULT hr = _SetThreadDescription(current, unicode_name);
+      if (FAILED(hr)) {
+        log_debug(os, thread)("set_native_thread_name: SetThreadDescription failed - falling back to debugger method");
+        FREE_C_HEAP_ARRAY(WCHAR, unicode_name);
+      } else {
+        log_trace(os, thread)("set_native_thread_name: SetThreadDescription succeeded - new name: %s", name);
+
+#ifdef ASSERT
+        // For verification purposes in a debug build we read the thread name back and check it.
+        PWSTR thread_name;
+        HRESULT hr2 = _GetThreadDescription(current, &thread_name);
+        if (FAILED(hr2)) {
+          log_debug(os, thread)("set_native_thread_name: GetThreadDescription failed!");
+        } else {
+          int res = CompareStringW(LOCALE_USER_DEFAULT,
+                                   0, // no special comparison rules
+                                   unicode_name,
+                                   -1, // null-terminated
+                                   thread_name,
+                                   -1  // null-terminated
+                                   );
+          assert(res == CSTR_EQUAL,
+                 "Name strings were not the same - set: %ls, but read: %ls", unicode_name, thread_name);
+          LocalFree(thread_name);
+        }
+#endif
+        FREE_C_HEAP_ARRAY(WCHAR, unicode_name);
+        return;
+      }
+    } else {
+      log_debug(os, thread)("set_native_thread_name: convert_to_unicode failed - falling back to debugger method");
+    }
+  }
+
   // See: http://msdn.microsoft.com/en-us/library/xcb2z8hs.aspx
   //
   // Note that unfortunately this only works if the process
@@ -895,6 +949,7 @@ void os::set_native_thread_name(const char *name) {
 
   // If there is no debugger attached skip raising the exception
   if (!IsDebuggerPresent()) {
+    log_debug(os, thread)("set_native_thread_name: no debugger present so unable to set thread name");
     return;
   }
 
@@ -4193,6 +4248,7 @@ extern "C" {
 
 static jint initSock();
 
+
 // this is called _after_ the global arguments have been parsed
 jint os::init_2(void) {
 
@@ -4311,6 +4367,24 @@ jint os::init_2(void) {
     jdk_misc_signal_init();
   }
 
+  // Lookup SetThreadDescription - the docs state we must use runtime-linking of
+  // kernelbase.dll, so that is what we do.
+  HINSTANCE _kernelbase = LoadLibrary(TEXT("kernelbase.dll"));
+  if (_kernelbase != NULL) {
+    _SetThreadDescription =
+      reinterpret_cast<SetThreadDescriptionFnPtr>(
+                                                  GetProcAddress(_kernelbase,
+                                                                 "SetThreadDescription"));
+#ifdef ASSERT
+    _GetThreadDescription =
+      reinterpret_cast<GetThreadDescriptionFnPtr>(
+                                                  GetProcAddress(_kernelbase,
+                                                                 "GetThreadDescription"));
+#endif
+  }
+  log_info(os, thread)("The SetThreadDescription API is%s available.", _SetThreadDescription == NULL ? " not" : "");
+
+
   return JNI_OK;
 }
 

test/hotspot/jtreg/runtime/logging/ThreadLoggingTest.java

@@ -62,7 +62,7 @@ public class ThreadLoggingTest {
         pb = ProcessTools.createJavaProcessBuilder("-Xlog:os+thread=debug", "-version");
         output = new OutputAnalyzer(pb.start());
         analyzeOutputForDebugLevel(output);
-
+        output.reportDiagnosticSummary();
     }
 
 }