modified   .gitignore
@@ -33,6 +33,9 @@
 /configure
 src/config.in
 
+# Built by dtrace
+src/emacs-dtrace.h
+
 # Built by 'configure'.
 Info.plist
 InfoPlist.strings
modified   configure.ac
@@ -1294,6 +1294,7 @@ AC_DEFUN
   passthrough="$passthrough --with-threads=$with_threads"
   passthrough="$passthrough --with-rsvg=$with_rsvg"
   passthrough="$passthrough --with-mps=$with_mps"
+  passthrough="$passthrough --with-dtrace=$with_dtrace"
 
   # Now pass through some checking-related options.
   emacs_val="--enable-check-lisp-object-type=$enable_check_lisp_object_type"
@@ -5648,7 +5649,6 @@ AC_DEFUN
   fi
 fi
 
-
 if test "$REALLY_ANDROID" = "yes" && test "$with_mps" != "no"; then
   HAVE_MPS=no
   ndk_SEARCH_MODULE([mps], [MPS], [HAVE_MPS=yes])
@@ -5669,6 +5669,29 @@ AC_DEFUN
 AC_SUBST([LIBMPS])
 AC_SUBST([IGCOBJ])
 
+### Use DTrace if available, unless '--with-dtrace=no'.
+AC_SUBST([DTRACE])
+AC_SUBST([DTRACE_OBJ])
+AC_SUBST([HAVE_DTRACE])
+DTRACE=
+DTRACE_OBJ=
+HAVE_DTRACE=no
+if test "${with_dtrace}" != "no"; then
+  AC_PATH_PROG([DTRACE], [dtrace], [])
+  if test "$DTRACE" = ""; then
+    AC_MSG_ERROR([dtrace command not found])
+  fi
+  AC_DEFINE([HAVE_DTRACE], [1],
+    [Define to 1 if you have the dtrace command.])
+  HAVE_DTRACE=yes
+
+  # DTrace providers have to be linked into an application, normally,
+  # except on Darwin. DTRACE_OBJ is added to the object files needed
+  # for Emacs in src/Makefile.in.
+  if test "$opsys" != darwin; then
+    DTRACE_OBJ=emacs-dtrace.o
+  fi
+fi
 
 dnl Check for malloc/malloc.h on darwin
 AC_CHECK_HEADERS_ONCE([malloc/malloc.h])
@@ -7875,6 +7898,7 @@ AC_DEFUN
   Does Emacs have native lisp compiler?                   ${HAVE_NATIVE_COMP}
   Does Emacs use version 2 of the X Input Extension?      ${HAVE_XINPUT2}
   Does Emacs generate a smaller-size Japanese dictionary? ${with_small_ja_dic}
+  Does Emacs use dtrace?                                  ${HAVE_DTRACE}
 "])
 
 if test -n "${EMACSDATA}"; then
modified   src/Makefile.in
@@ -366,6 +366,33 @@ LIBGPM =
 LIBMPS = @LIBMPS@
 IGCOBJ = @IGCOBJ@
 
+#-----------------------------------------------------------------------
+# DTrace
+#-----------------------------------------------------------------------
+
+HAVE_DTRACE = @HAVE_DTRACE@
+DTRACE = @DTRACE@
+# Empty if linking not required by the OS.
+DTRACE_OBJ = @DTRACE_OBJ@
+
+ifeq ($(HAVE_DTRACE),yes)
+
+# Produce header file with DTrace probe macros.
+$(srcdir)/emacs-dtrace.h: $(srcdir)/emacs-dtrace.d
+	$(DTRACE) -o $@ -h -s $<
+
+# Build DTrace object file (untested). This is not triggered if
+# DTRACE_OBJ is empty, which it is on macOS. So we won't use the -G
+# switch which doesn't exist on macOS.
+emacs-dtrace.o: $(srcdir)/emacs-dtrace.d
+	$(DTRACE) -o $@ -G -s $<
+
+# Make objects that use probes dependent on the probe header.
+igc.o: $(srcdir)/emacs-dtrace.h
+
+endif
+#-----------------------------------------------------------------------
+
 LIBSELINUX_LIBS = @LIBSELINUX_LIBS@
 LIBSELINUX_CFLAGS = @LIBSELINUX_CFLAGS@
 
@@ -487,7 +514,7 @@ base_obj =
 	doprnt.o intervals.o textprop.o composite.o xml.o lcms.o $(NOTIFY_OBJ) \
 	$(XWIDGETS_OBJ) 						       \
 	profiler.o decompress.o 					       \
-	pkg.o $(IGCOBJ)							       \
+	pkg.o $(IGCOBJ) $(DTRACE_OBJ)					       \
 	thread.o systhread.o sqlite.o  treesit.o			       \
 	itree.o json.o 							       \
 	$(if $(HYBRID_MALLOC),sheap.o) 					       \
new file   src/emacs-dtrace.d
@@ -0,0 +1,12 @@
+/* Emacs DTrace provider. */
+
+provider emacs {
+    probe test_probe(const char *);
+};
+
+/* See https://docs.oracle.com/cd/E19253-01/817-6223/chp-usdt/index.html */
+#pragma D attributes Evolving/Evolving/Common provider emacs provider
+#pragma D attributes Evolving/Evolving/Common provider emacs module
+#pragma D attributes Evolving/Evolving/Common provider emacs function
+#pragma D attributes Evolving/Evolving/Common provider emacs name
+#pragma D attributes Evolving/Evolving/Common provider emacs args
modified   src/igc.c
@@ -5173,6 +5173,24 @@ DEFUN ("igc--remove-extra-dependency", Figc__remove_extra_dependency,
   return Qt;
 }
 
+/***********************************************************************
+				  DTrace
+ ***********************************************************************/
+
+#ifdef HAVE_DTRACE
+#include "emacs-dtrace.h"
+
+DEFUN ("igc-test-probe", Figc_test_probe, Sigc_test_probe, 1, 1, 0, doc: /* */)
+  (Lisp_Object msg)
+{
+  CHECK_SUBR (msg);
+  if (EMACS_TEST_PROBE_ENABLED ())
+    EMACS_TEST_PROBE (SSDATA (msg));
+  return Qnil;
+}
+
+#endif /* HAVE_DTRACE */
+
 /***********************************************************************
 				  Init
  ***********************************************************************/
@@ -5196,6 +5214,10 @@ syms_of_igc (void)
   defsubr (&Sigc__set_commit_limit);
   defsubr (&Sigc__add_extra_dependency);
   defsubr (&Sigc__remove_extra_dependency);
+#ifdef HAVE_DTRACE
+  defsubr (&Sigc_test_probe);
+#endif
+
   DEFSYM (Qambig, "ambig");
   DEFSYM (Qexact, "exact");
   Fprovide (intern_c_string ("mps"), Qnil);