diff -r 3e4ce5ec50fd lua/userver/controller.lua
--- a/lua/userver/controller.lua	Tue Jun 13 11:23:19 2017 +0300
+++ b/lua/userver/controller.lua	Thu Jun 22 20:27:57 2017 +0300
@@ -710,7 +710,14 @@
    local action = get_param('action')
    if action == 'start' then
       local file_name
-      if get_param('leaf') == '1' then
+      local PROFILER_MODES = {
+          ["default"] = "default",
+          ["leaf"] = "leaf",
+          ["callgraph"] = "callgraph",
+      }
+      local mode = PROFILER_MODES[get_param('mode')] or error ("Wrong profiler mode");
+
+      if not (mode == 'default') then
          file_name = userver.table.pindex(
             server_conf, 'lua', 'jit', 'profile', 'file_name')
          if not file_name then
@@ -719,7 +726,7 @@
       end

       local interval = tonumber(get_param('interval')) or 100 -- microseconds
-      local started  = debug.profile.start(interval, file_name)
+      local started  = debug.profile.start(interval, mode, file_name)

       response.content = started and 'OK' or 'Already started'