What is spindump?

If you have seen the spinning beach ball and then spotted spindump in Activity Monitor, here is the link between them.

What is spindump?

spindump finds and records app hangs. When an app stops responding and shows the spinning wait cursor (the beach ball), spindump takes a snapshot of what the app was doing at that moment.

What does it capture?

When an app hangs, spindump takes a series of stack trace samples from the stuck process. These samples show which code was running (or stuck) when the hang happened. This is very useful for developers trying to fix slowdowns.

The result is called a "spin report" or "hang report".

When does it run?

spindump starts when:

• An app stops responding and shows the spinning wait cursor
• You force-quit an app (it records the hang state before killing the app)
• The system spots a process that is not answering events
• You run it yourself from the command line

Where are the reports saved?

Hang reports go to /Library/Logs/DiagnosticReports/ and ~/Library/Logs/DiagnosticReports/. You can also view them in Console.app.

You can capture a spindump yourself:

sudo spindump -reveal

Does it use many resources?

Briefly, while sampling the stuck process. The capture usually takes a few seconds. If spindump keeps using the processor, it likely means another process keeps hanging.

Should you worry?

No. spindump helps find out why apps freeze. If you see it running often, the problem is the app that keeps hanging, not spindump.

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