Re: [Xen-devel] [Qemu-devel] [PATCH v3 6/6] qemu_calculate_timeout: increase minimum timeout to 1h

[Paul Brook <paul@xxxxxxxxxxxxxxxx>]

> There is no reason why the minimum timeout should be 1sec, it could
> easily be 1h and we would save lots of cpu cycles.

No.

The reason we have this is because there are bits of code that rely on 
polling.  IIRC slirp and the floppy DMA engine were the main culprits. 
qemu_calculate_timeout is an ugly hack to poll at least once a second, 
allowing the guest to make forward progress when we miss an event.

If you think you've fixed all those polling places then you should remove the 
timeout altogether and block indefinitely.  A 1h timeout is almost certainly 
not the right answer.

Paul

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