watchdog reloader uses excessive CPU #3054

the watchdog reloader calls run_step every second by default

I ran py-spy record --pid ... --output profile.speedscope.json --format speedscope for about 8 seconds on an idle app. you can place profile.speedscope.json into https://www.speedscope.app/ and see 8 calls to run() which take about 150ms each:

increasing ReloaderLoop.interval helps a lot, but means reloads have to wait for the next iteration

Environment:

• Python version: 3.12.7
• Werkzeug version: 3.0.6