Re: [PATCH 4/4] input: evdev: only wake poll on EV_SYN

From: Dmitry Torokhov
Date: Fri Mar 25 2011 - 03:49:30 EST


On Tue, Mar 22, 2011 at 06:04:04PM -0700, Jeff Brown wrote:
> On SMP systems, it is possible for an evdev client blocked on poll()
> to wake up and read events from the evdev ring buffer at the same
> rate as they are enqueued. This can result in high CPU usage,
> particularly for MT devices, because the client ends up reading
> events one at a time instead of reading complete packets. This patch
> ensures that the client only wakes from poll() when a complete packet
> is ready to be read.

Doesn't this only help with very first packet after a pause in event
stream?

--
Dmitry
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