diff --git a/test/data/ui-screenshots/wattson.test.ts/sched-aggregations/sched-aggr-process.png.sha256 b/test/data/ui-screenshots/wattson.test.ts/sched-aggregations/sched-aggr-process.png.sha256
new file mode 100644
index 0000000000..f411fafdfb
--- /dev/null
+++ b/test/data/ui-screenshots/wattson.test.ts/sched-aggregations/sched-aggr-process.png.sha256
@@ -0,0 +1 @@
+f34bf2a4e27e532ae99819fc3f9595be853383bf929756f1261a311d6ff3a572
\ No newline at end of file
diff --git a/test/data/ui-screenshots/wattson.test.ts/sched-aggregations/sched-aggr-thread.png.sha256 b/test/data/ui-screenshots/wattson.test.ts/sched-aggregations/sched-aggr-thread.png.sha256
new file mode 100644
index 0000000000..1b81a92b09
--- /dev/null
+++ b/test/data/ui-screenshots/wattson.test.ts/sched-aggregations/sched-aggr-thread.png.sha256
@@ -0,0 +1 @@
+af2e494f4ac1ca9a1121d276509e36fda60caa5b03c5538d024ee89297d34d31
\ No newline at end of file
diff --git a/test/data/ui-screenshots/wattson.test.ts/wattson-aggregations/wattson-estimate-aggr.png.sha256 b/test/data/ui-screenshots/wattson.test.ts/wattson-aggregations/wattson-estimate-aggr.png.sha256
new file mode 100644
index 0000000000..f46669a97e
--- /dev/null
+++ b/test/data/ui-screenshots/wattson.test.ts/wattson-aggregations/wattson-estimate-aggr.png.sha256
@@ -0,0 +1 @@
+2795614d6dd948b0a0150e116c29a51a5e85abf45982ccde6a93d24b0f44dfdf
\ No newline at end of file
diff --git a/ui/src/common/plugins.ts b/ui/src/common/plugins.ts
index c218db6738..55c017c9b5 100644
--- a/ui/src/common/plugins.ts
+++ b/ui/src/common/plugins.ts
@@ -154,6 +154,10 @@ export class PluginManager {
     }
   }
 
+  hasPlugin(pluginId: string): boolean {
+    return pluginRegistry.has(pluginId);
+  }
+
   isActive(pluginId: string): boolean {
     return this.getPluginContext(pluginId) !== undefined;
   }
diff --git a/ui/src/frontend/index.ts b/ui/src/frontend/index.ts
index 8dcd714807..02d8f69f51 100644
--- a/ui/src/frontend/index.ts
+++ b/ui/src/frontend/index.ts
@@ -376,6 +376,13 @@ function onCssLoaded() {
 
   // Initialize plugins, now that we are ready to go
   pluginManager.initialize();
+
+  const route = Router.parseUrl(window.location.href);
+  for (const pluginId of (route.args.enablePlugins ?? '').split(',')) {
+    if (pluginManager.hasPlugin(pluginId)) {
+      pluginManager.activatePlugin(pluginId);
+    }
+  }
 }
 
 // If the URL is /#!?rpc_port=1234, change the default RPC port.
diff --git a/ui/src/frontend/router.ts b/ui/src/frontend/router.ts
index 5df1840d10..e865b07e98 100644
--- a/ui/src/frontend/router.ts
+++ b/ui/src/frontend/router.ts
@@ -76,6 +76,9 @@ const ROUTE_SCHEMA = z
     // Should we hide the sidebar?
     hideSidebar: z.boolean().optional().catch(undefined),
 
+    // A comma-separated list of plugins to enable for the current session.
+    enablePlugins: z.string().optional().catch(undefined),
+
     // Deep link support
     ts: z.string().optional().catch(undefined),
     dur: z.string().optional().catch(undefined),
diff --git a/ui/src/test/perfetto_ui_test_helper.ts b/ui/src/test/perfetto_ui_test_helper.ts
index 40bbe40310..27ea7a1e71 100644
--- a/ui/src/test/perfetto_ui_test_helper.ts
+++ b/ui/src/test/perfetto_ui_test_helper.ts
@@ -47,8 +47,12 @@ export class PerfettoTestHelper {
     await this.page.click('body');
   }
 
-  async openTraceFile(traceName: string): Promise<void> {
-    await this.page.goto('/?testing=1');
+  async openTraceFile(traceName: string, args?: {}): Promise<void> {
+    args = {testing: '1', ...args};
+    const qs = Object.entries(args ?? {})
+      .map(([k, v]) => `${k}=${v}`)
+      .join('&');
+    await this.page.goto('/?' + qs);
     const file = await this.page.waitForSelector('input.trace_file', {
       state: 'attached',
     });
diff --git a/ui/src/test/wattson.test.ts b/ui/src/test/wattson.test.ts
new file mode 100644
index 0000000000..7f660d2c13
--- /dev/null
+++ b/ui/src/test/wattson.test.ts
@@ -0,0 +1,74 @@
+// Copyright (C) 2024 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+import {test, Page} from '@playwright/test';
+import {PerfettoTestHelper} from './perfetto_ui_test_helper';
+import {assertExists} from '../base/logging';
+
+test.describe.configure({mode: 'serial'});
+
+let pth: PerfettoTestHelper;
+let page: Page;
+
+// Clip only the bottom half of the UI. When dealing with area selection, the
+// time-width of the mouse-based region (which then is showed up in the upper
+// ruler) is not 100% reproducible.
+const SCREEN_CLIP = {
+  clip: {
+    x: 230,
+    y: 500,
+    width: 1920,
+    height: 1080,
+  },
+};
+
+test.beforeAll(async ({browser}, _testInfo) => {
+  page = await browser.newPage();
+  pth = new PerfettoTestHelper(page);
+  await pth.openTraceFile('wattson_dsu_pmu.pb', {
+    enablePlugins: 'org.kernel.Wattson',
+  });
+});
+
+test('wattson aggregations', async () => {
+  const wattsonGrp = pth.locateTrackGroup('Wattson');
+  await wattsonGrp.scrollIntoViewIfNeeded();
+  await pth.toggleTrackGroup(wattsonGrp);
+  const cpuEstimate = pth.locateTrack('Wattson/Cpu0 Estimate', wattsonGrp);
+  const coords = assertExists(await cpuEstimate.boundingBox());
+  await page.keyboard.press('Escape');
+  await page.mouse.move(600, coords.y + 10);
+  await page.mouse.down();
+  await page.mouse.move(1000, coords.y + 80);
+  await page.mouse.up();
+  await pth.waitForIdleAndScreenshot('wattson-estimate-aggr.png', SCREEN_CLIP);
+  await page.keyboard.press('Escape');
+});
+
+test('sched aggregations', async () => {
+  await page.keyboard.press('Escape');
+  await page.mouse.move(600, 250);
+  await page.mouse.down();
+  await page.mouse.move(800, 350);
+  await page.mouse.up();
+  await pth.waitForPerfettoIdle();
+
+  await page.click('button[label="Wattson by thread"]');
+  await pth.waitForIdleAndScreenshot('sched-aggr-thread.png', SCREEN_CLIP);
+
+  await page.click('button[label="Wattson by process"]');
+  await pth.waitForIdleAndScreenshot('sched-aggr-process.png', SCREEN_CLIP);
+
+  await page.keyboard.press('Escape');
+});