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Jeff Brown authored
This patch modifies evdev so that it only becomes readable when the buffer contains an EV_SYN/SYN_REPORT event. 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. We eliminate this problem by making the device readable only when the buffer contains at least one complete packet. This causes clients to block until the entire packet is available. Signed-off-by:
Jeff Brown <jeffbrown@android.com> Signed-off-by:
Dmitry Torokhov <dtor@mail.ru>
cdda911c