Hi folks, I was paying attention to a different window of Firefox (v68.0.1) when I noticed a banner saying “A page is slowing down performance” appear in a window for a notebook I had open behind it. The notebook in question was the only tab open in that window, so I profiled its performance after …

The 5-minute intro has one cell that does: i = { let i = 0; while (true) { yield ++i; } } And another cell that does: date = { while (true) { yield new Promise(resolve => { setTimeout(() => resolve(new Date), 1000); }); } } These just keep running in an infinite loop. …

Yes, as I mentioned in my post, I have those cells commented.

Looks like these happen regularly (every 4–5 seconds, accompanied by a DOM event). My guess is that this is a heartbeat used for updating the notebook when it gets changed somewhere externally to the page. But it could be something else. I think maybe the inspector performance tab is showing you ev…

Thank you for looking into the behavior on your machine. The notebook in question didn’t contain any cells that regularly re-rendered or re-ran on any kind of schedule, nor any code that would (or, I ought to say, that should) block the main thread, let alone any code that would have been expensive …

The worker process is shared between multiple notebooks: [image] Notebooks not rendering My workflow for hanging Observable tabs is: If I know it’s the current tab that’s causing the perfomance drain, I open up the Sources tab in dev tools and pause, then stop, the worker thread. Otherwise I p…

The only interval that runs always regardless of notebook content is a 5s interval we use to detect infinite loops. If notebook content delays the event loop by two 5s heartbeats, then we show a message that tells folks that the notebook probably is in an infinite loop and you’ll want to fix it in s…

Are all of these setTimeout and setInterval calls normal?

Help

mootari August 7, 2019, 8:23pm 6

The worker process is shared between multiple notebooks:

New notebook not loading / responding

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Are all of these setTimeout and setInterval calls normal?

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