[Xen-devel] [PATCH 0/4] prevent Qemu from waking up needlessly

[Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>]

Hi all,
this small patch series prevents Qemu from waking up needlessly on Xen
several times a second in order to check some timers.

The first two patches stop Qemu from emulating the RTC and the PIT on
Xen, that are both already emulated in the hypervisor and consume
precious cpu cycles because they need qemu-timers to work.

The third patch makes use of a new mechanism to receive buffered io
event notifications from Xen, so that Qemu doesn't need to check the
buffered io page for data 10 times a sec for the entire life of the VM.

Finally the last patch increases the default select timeout to 1h:
nothing should rely on the select timeout to be 1sec, so we might as
well increase it to 1h.


Stefano Stabellini (4):
      xen: introduce mc146818rtcxen
      xen: do not initialize the interval timer emulator
      xen: introduce an event channel for buffered io event notifications
      qemu_calculate_timeout: increase minimum timeout to 1h

 hw/mc146818rtc.c |   36 +++++++++++++++++++++++++++++++++++-
 hw/pc.c          |    7 +++++--
 qemu-timer.c     |    2 +-
 xen-all.c        |   38 ++++++++++++++++++++++++++++++++------
 4 files changed, 73 insertions(+), 10 deletions(-)


A git tree based on v1.0-rc2 is available here:

git://xenbits.xen.org/people/sstabellini/qemu-dm.git timers-1.0-rc2

Cheers,

Stefano

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