--- a/devtools/server/actors/perf.js
+++ b/devtools/server/actors/perf.js
@@ -40,28 +40,28 @@ exports.PerfActor = ActorClassWithSpec(p
     }
     Services.obs.removeObserver(this._observer, "profiler-started");
     Services.obs.removeObserver(this._observer, "profiler-stopped");
     Services.obs.removeObserver(this._observer, "chrome-document-global-created");
     Services.obs.removeObserver(this._observer, "last-pb-context-exited");
     Actor.prototype.destroy.call(this);
   },
 
-  startProfiler() {
+  startProfiler(options) {
     if (!IS_SUPPORTED_PLATFORM) {
       return false;
     }
 
     // For a quick implementation, decide on some default values. These may need
     // to be tweaked or made configurable as needed.
     const settings = {
-      entries: 1000000,
-      interval: 1,
-      features: ["js", "stackwalk", "threads", "leaf"],
-      threads: ["GeckoMain", "Compositor"]
+      entries: options.entries || 1000000,
+      interval: options.interval || 1,
+      features: options.features || ["js", "stackwalk", "threads", "leaf"],
+      threads: options.threads || ["GeckoMain", "Compositor"]
     };
 
     try {
       // This can throw an error if the profiler is in the wrong state.
       Services.profiler.StartProfiler(
         settings.entries,
         settings.interval,
         settings.features,

--- a/devtools/shared/specs/perf.js
+++ b/devtools/shared/specs/perf.js
@@ -1,14 +1,14 @@
 /* This Source Code Form is subject to the terms of the Mozilla Public
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 "use strict";
 
-const { RetVal, generateActorSpec } = require("devtools/shared/protocol");
+const { Option, RetVal, generateActorSpec } = require("devtools/shared/protocol");
 
 const perfDescription = {
   typeName: "perf",
 
   events: {
     "profiler-started": {
       type: "profiler-started"
     },
@@ -20,17 +20,22 @@ const perfDescription = {
     },
     "profile-unlocked-from-private-browsing": {
       type: "profile-unlocked-from-private-browsing"
     }
   },
 
   methods: {
     startProfiler: {
-      request: {},
+      request: {
+        entries: Option(0, "number"),
+        interval: Option(0, "number"),
+        features: Option(0, "array:string"),
+        threads: Option(0, "array:string"),
+      },
       response: { value: RetVal("boolean") }
     },
 
     /**
      * Returns null when unable to return the profile.
      */
     getProfileAndStopProfiler: {
       request: {},