Re: [PATCH 0/3] kvm tools: remove periodic tick

[Pekka Enberg <penberg@iki.fi>]

On 9/3/13 9:10 PM, Jonathan Austin wrote:
> This patch series removes kvm tool's periodic tick function in favour of a
> thread that blocks waiting for input. The paths used for handling input are the
> same as when using a periodic tick, but they're not called unless there is
> actually input to be processed.
>
> On extremely slow platforms (eg FPGAs) the overhead involved in handling the
> timer tick means it is possible to make progress at all inside the VM! This
> patch addresses this problem.
>
> In doing this there are a number of small tidyups/cleanups that made sense, too:
> - Use a #define for maximum number of term devices
> - Refactor the method by which the virtio console handles input in order not to
>    - handle input too early
>    - handle input multiple times if the worker thread didn't immediately start
>      work.
> - Rename the periodic_poll function to reflect the functional change
>
> Jonathan Austin (3):
>    kvm tools: use #define for maximum number of terminal devices
>    kvm tools: remove periodic tick in favour of a polling thread
>    kvm tools: stop virtio console doing unnecessary input handling
>
>   tools/kvm/arm/kvm.c         |    2 +-
>   tools/kvm/builtin-run.c     |   13 -----------
>   tools/kvm/include/kvm/kvm.h |    2 +-
>   tools/kvm/kvm.c             |   50 -------------------------------------------
>   tools/kvm/powerpc/kvm.c     |    2 +-
>   tools/kvm/term.c            |   38 +++++++++++++++++++++++++++++---
>   tools/kvm/virtio/console.c  |   23 +++++++++++++++++---
>   tools/kvm/x86/kvm.c         |    2 +-
>   8 files changed, 59 insertions(+), 73 deletions(-)

Seems reasonable to me. Marc, Will?

                         Pekka