Re: [PATCH 1/4] kvm tools: Add ioeventfd support

[Sasha Levin <levinsasha928@gmail.com>]

On Fri, 2011-05-27 at 11:47 +0100, Stefan Hajnoczi wrote:
> On Fri, May 27, 2011 at 11:36 AM, Sasha Levin <levinsasha928@gmail.com> wrote:
> > ioeventfd is way provided by KVM to receive notifications about
> > reads and writes to PIO and MMIO areas within the guest.
> >
> > Such notifications are usefull if all we need to know is that
> > a specific area of the memory has been changed, and we don't need
> > a heavyweight exit to happen.
> >
> > The implementation uses epoll to scale to large number of ioeventfds.
> >
> > Signed-off-by: Sasha Levin <levinsasha928@gmail.com>
> > ---
> >  tools/kvm/Makefile                |    1 +
> >  tools/kvm/include/kvm/ioeventfd.h |   27 ++++++++
> >  tools/kvm/ioeventfd.c             |  127 +++++++++++++++++++++++++++++++++++++
> >  tools/kvm/kvm-run.c               |    4 +
> >  4 files changed, 159 insertions(+), 0 deletions(-)
> >  create mode 100644 tools/kvm/include/kvm/ioeventfd.h
> >  create mode 100644 tools/kvm/ioeventfd.c
> 
> Did you run any benchmarks?
> 
> Stefan

Yes, they showed a nice improvements - I'll post them with a V2 of the
patch.

-- 

Sasha.