diff --git a/runtime/indent/testdir/tools/tracer.vim b/runtime/indent/testdir/tools/tracer.vim
new file mode 100644
index 0000000..d873154
--- /dev/null
+++ b/runtime/indent/testdir/tools/tracer.vim
@@ -0,0 +1,166 @@
+vim9script
+
+# Whenever indent plugins contain "search*()" lines explicitly annotated with
+# "VIM_INDENT_TEST_TRACE_(START|END)" comment markers; this script can then be
+# used as shown to measure and record elapsed time for such decorated calls.
+#
+# Usage:
+#	cd runtime/indent
+#	vim -u NONE -S testdir/tools/tracer.vim \
+#		html.vim javascript.vim \
+#		../autoload/python.vim ../autoload/dist/vimindent.vim
+#	git diff
+#	make clean test
+#	vim testdir/00-TRACE_LOG.fail
+
+def GenerateTempletForTracing(fname: string, vname: string): list<string>
+  #### ONLY INSTRUMENT "search*()"es FOR INDENT TESTS.
+
+  const templet: list<string> =<< trim eval END
+
+  if getcwd() =~# '\<runtime/indent$'
+
+  def! g:IndentTestTrace(id: string, start: list<number>, result: any): any
+    const end: list<number> = reltime(start)
+
+    if !has_key(g:indent_test_trace_times, id)
+      g:indent_test_trace_times[id] = []
+    endif
+
+    g:indent_test_trace_times[id]
+	->add(reltimefloat(end))
+    return result
+  enddef
+
+  def! g:IndentTestInitTracing()
+    # Possibly use a later "{fname}", cf. ":runtime indent/foo.vim".
+    autocmd_add([{{
+	replace: true,
+	group:	'tracing',
+	event:	'QuitPre',
+	bufnr:	bufnr(),
+	cmd:	'g:IndentTestWriteTraceTimes()',
+      }}])
+    g:indent_test_trace_times = {{}}
+  enddef
+
+  def! g:IndentTestWriteTraceTimes()
+    # Anticipate usage by multiple languages.
+    const token: string = printf('%02x', (rand() % 26))
+    writefile(['" {fname}:',
+	    "let {vname}_" .. token .. " = " .. string(g:indent_test_trace_times),
+	    "let {vname}_" .. token .. "_summary = " .. string(g:indent_test_trace_times
+		->items()
+		->reduce((outer: dict<dict<any>>, times: list<any>) =>
+		    extend({{[times[0]]: times[1]
+			      ->copy()
+			      ->reduce((inner: dict<any>, v: float) =>
+				  extend({{
+				      min: inner.min < v ? inner.min : v,
+				      max: inner.max > v ? inner.max : v,
+				      sum: (inner.sum + v),
+				      avg: ((inner.sum + v) / inner.count),
+				    }},
+				    inner,
+				    "keep"),
+				  {{
+				      min: v:numbermax - 0.0,
+				      max: v:numbermin + 0.0,
+				      sum: 0.0,
+				      avg: 0.0,
+				      count: len(times[1]),
+				  }})}},
+			    outer),
+			{{}}))],
+	(!empty($VIM_INDENT_TEST_LOG) && filewritable($VIM_INDENT_TEST_LOG))
+	    ? $VIM_INDENT_TEST_LOG
+	    : "testdir/00-TRACE_LOG.fail",
+	"a")
+  enddef
+
+  call g:IndentTestInitTracing()
+
+  else
+
+  def! g:IndentTestTrace(_: string, _: list<number>, result: any): any
+    return result
+  enddef
+
+  endif
+
+  END
+  return templet
+enddef
+
+def InstrumentMarkedEntry(): bool
+  const marker_start: string = 'VIM_INDENT_TEST_TRACE_START'
+  const start: number = search('\C\<' .. marker_start .. '\>', 'ceW')
+
+  if start == 0
+    return false
+  endif
+
+  const marker_end: string = 'VIM_INDENT_TEST_TRACE_END'
+  const end: number = search('\C\<' .. marker_end .. '\>', 'ceW')
+
+  if end == 0
+    return false
+  endif
+
+  const tracee: list<string> = matchlist(
+    getline(start + 1),
+    '\(^.\+\)\(\<search\%(pair\)\=\%(pos\)\=\s*(.*$\)')
+
+  if empty(get(tracee, 1, '')) || empty(get(tracee, 2, ''))
+    return false
+  endif
+
+  const end_line: string = getline(end)
+  const tracer: string = printf('%sg:IndentTestTrace("%s", reltime(), %s',
+      tracee[1],
+      strpart(end_line, (stridx(end_line, marker_end) + strlen(marker_end) + 1)),
+      tracee[2])
+
+  if (end - start) > 1
+    setline((start + 1), tracer)
+    setline((end - 1), getline(end - 1) .. ')')
+  else
+    setline((start + 1), tracer .. ')')
+  endif
+
+  return true
+enddef
+
+def ProcessIndentPluginCmdlineArgs()
+  const names: list<string> = range(char2nr('a'), char2nr('z'))
+      ->map((_: number, n: number) => nr2char(n, true))
+  var entries: number = 0
+  var next: number = 0
+
+  for fname: string in argv(-1)
+    if filereadable(fname) && filewritable(fname)
+      execute 'new ' .. fname
+      call cursor(1, 1)
+
+      while InstrumentMarkedEntry()
+	entries += 1
+      endwhile
+
+      if entries > 0
+	append(1, GenerateTempletForTracing(fname, get(names, next, names[-1])))
+	wq
+      endif
+
+      entries = 0
+      next += 1
+    endif
+  endfor
+enddef
+
+if empty(system('git status --porcelain=v1'))
+  ProcessIndentPluginCmdlineArgs()
+endif
+
+quitall
+
+# vim:fdm=syntax:sw=2:ts=8:noet:nosta: