Re: [Qemu-devel] [v2 0/2] Optimize the env->tsc update operation

[Paolo Bonzini <pbonzini@redhat.com>]

On 05/11/2015 04:51, Liang Li wrote:
> This patch set aims for reducing the live migration downtime. It
> updates the env->tsc when stopping kvmclock with a new function.
> Rather than using 'cpu_synchronize_all_states()', which updates the
> whole CPU context just for updating the env->tsc.
> 
> For a VM with 4 CPUs, this patch set can help to reduce the VM downtime
> about 100us.
> 
> Changes in v2:
>   * Simplify 'kvm_get_tsc()' function.
>   * Introduce a new function 'kvm_synchronize_all_tsc()'
> 
> Liang Li (2):
>   kvmclock: add a new function to update env->tsc.
>   Revert "Introduce cpu_clean_all_dirty"
> 
>  cpus.c                 |  9 ---------
>  hw/i386/kvm/clock.c    | 18 ++----------------
>  include/sysemu/cpus.h  |  1 -
>  include/sysemu/kvm.h   |  8 --------
>  kvm-all.c              |  5 -----
>  target-i386/kvm.c      | 45 +++++++++++++++++++++++++++++++++++++++++++++
>  target-i386/kvm_i386.h |  1 +
>  7 files changed, 48 insertions(+), 39 deletions(-)
> 

Nice, I've applied these patches.

Paolo