On Fri, 10 Apr 2020 at 23:17, Paolo Bonzini <pbonzini@xxxxxxxxxx> wrote:
>
> On 10/04/20 03:03, Wanpeng Li wrote:
> > From: Wanpeng Li <wanpengli@xxxxxxxxxxx>
> >
> > IPI and Timer cause the main MSRs write vmexits in cloud environment
> > observation, let's optimize virtual IPI latency more aggressively to
> > inject target IPI as soon as possible.
> >
> > Running kvm-unit-tests/vmexit.flat IPI testing on SKX server, disable
> > adaptive advance lapic timer and adaptive halt-polling to avoid the
> > interference, this patch can give another 7% improvement.
> >
> > w/o fastpath -> fastpath 4238 -> 3543 16.4%
> > fastpath -> ultra fastpath 3543 -> 3293 7%
> > w/o fastpath -> ultra fastpath 4238 -> 3293 22.3%
> >
> > This also revises the performance data in commit 1e9e2622a1 (KVM: VMX:
> > FIXED+PHYSICAL mode single target IPI fastpath), that testing adds
> > --overcommit cpu-pm=on to kvm-unit-tests guest which is unnecessary.
> >
> > Tested-by: Haiwei Li <lihaiwei@xxxxxxxxxxx>
> > Cc: Haiwei Li <lihaiwei@xxxxxxxxxxx>
> > Signed-off-by: Wanpeng Li <wanpengli@xxxxxxxxxxx>
> > ---
> > v1 -> v2:
> > * rebase on latest kvm/queue
> > * update patch description
> >
> > arch/x86/include/asm/kvm_host.h | 6 +++---
> > arch/x86/kvm/svm/svm.c | 21 ++++++++++++++-------
> > arch/x86/kvm/vmx/vmx.c | 19 +++++++++++++------
> > arch/x86/kvm/x86.c | 4 ++--
> > 4 files changed, 32 insertions(+), 18 deletions(-)
>
> That's less ugly than I expected. :D I'll queue it in the next week or
> so. But even though the commit subject is cool, I'll change it to "KVM:
> x86: move IPI fastpath inside kvm_x86_ops.run".
Thanks.
Wanpeng
