linux-kernel - Re: [PATCH 0/4] Powerpc: Better preemption for shared processor

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Date:   Thu, 29 Oct 2020 12:44:20 +0530
From:   Srikar Dronamraju <srikar@...ux.vnet.ibm.com>
To:     Waiman Long <longman@...hat.com>
Cc:     Michael Ellerman <mpe@...erman.id.au>,
        linuxppc-dev <linuxppc-dev@...ts.ozlabs.org>,
        LKML <linux-kernel@...r.kernel.org>,
        Nicholas Piggin <npiggin@...il.com>,
        Nathan Lynch <nathanl@...ux.ibm.com>,
        Gautham R Shenoy <ego@...ux.vnet.ibm.com>,
        Peter Zijlstra <peterz@...radead.org>,
        Valentin Schneider <valentin.schneider@....com>,
        Juri Lelli <juri.lelli@...hat.com>,
        Phil Auld <pauld@...hat.com>
Subject: Re: [PATCH 0/4] Powerpc: Better preemption for shared processor

* Waiman Long <longman@...hat.com> [2020-10-28 20:01:30]:

> > Srikar Dronamraju (4):
> >    powerpc: Refactor is_kvm_guest declaration to new header
> >    powerpc: Rename is_kvm_guest to check_kvm_guest
> >    powerpc: Reintroduce is_kvm_guest
> >    powerpc/paravirt: Use is_kvm_guest in vcpu_is_preempted
> > 
> >   arch/powerpc/include/asm/firmware.h  |  6 ------
> >   arch/powerpc/include/asm/kvm_guest.h | 25 +++++++++++++++++++++++++
> >   arch/powerpc/include/asm/kvm_para.h  |  2 +-
> >   arch/powerpc/include/asm/paravirt.h  | 18 ++++++++++++++++++
> >   arch/powerpc/kernel/firmware.c       |  5 ++++-
> >   arch/powerpc/platforms/pseries/smp.c |  3 ++-
> >   6 files changed, 50 insertions(+), 9 deletions(-)
> >   create mode 100644 arch/powerpc/include/asm/kvm_guest.h
> > 
> This patch series looks good to me and the performance is nice too.
> 
> Acked-by: Waiman Long <longman@...hat.com>

Thank you.

> 
> Just curious, is the performance mainly from the use of static_branch
> (patches 1 - 3) or from reducing call to yield_count_of().

Because of the reduced call to yield_count

> 
> Cheers,
> Longman
> 

-- 
Thanks and Regards
Srikar Dronamraju