qemu-devel
[Top][All Lists]
Advanced

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [Qemu-devel] [PATCH V4 0/2] Add option to configure guest vPMU


From: Andrew Jones
Subject: Re: [Qemu-devel] [PATCH V4 0/2] Add option to configure guest vPMU
Date: Wed, 21 Sep 2016 09:38:47 +0200
User-agent: Mutt/1.6.0.1 (2016-04-01)

On Tue, Sep 20, 2016 at 10:33:52PM -0400, Wei Huang wrote:
> This patchset adds a pmu=[on/off] option to enable/disable vPMU support 
> for guest VM. There are several reasons to justify this option. First,
> vPMU can be problematic for cross-migration between different SoC as perf
> counters are architecture-dependent. It is more flexible to have an option
> to turn it on/off. Secondly this option matches the "pmu" option as
> supported in libvirt. To make sure backward compatible, a PMU-related
> property is added to mach-virt machine types.
> 
> The following are testing results with this patchset. Other combinations
> should have similar results:
>     CONFIG (qemu-system-aarch64)                    vPMU   WARNING
>     -M virt-2.7,accel=kvm -cpu host                  YES    NO
>     -M virt-2.7,accel=kvm -cpu host,pmu=off          NO     NO
>     -M virt-2.7,accel=kvm -cpu host,pmu=on           YES    NO
>     -M virt-2.6,accel=kvm -cpu host                  NO     NO
>     -M virt-2.6,accel=kvm -cpu host,pmu=off          NO     NO
>     -M virt-2.6,accel=kvm -cpu host,pmu=on           YES    NO
> 
>     -M virt-2.7,accel=tcg -cpu cortex-a57            NO     "No KVM"

We don't want this one above to warn.

>     -M virt-2.7,accel=tcg -cpu cortex-a57,pmu=off    NO     NO
>     -M virt-2.7,accel=tcg -cpu cortex-a57,pmu=on     NO     "No KVM"
>     -M virt-2.6,accel=tcg -cpu cortex-a57            NO     NO
>     -M virt-2.6,accel=tcg -cpu cortex-a57,pmu=off    NO     NO
>     -M virt-2.6,accel=tcg -cpu cortex-a57,pmu=on     NO     "No KVM"
> 
>     -M virt-2.7,accel=tcg -cpu cortex-a15            NO     NO
>     -M virt-2.7,accel=tcg -cpu cortex-a15,pmu=off    NO     "No PMU property"
>     -M virt-2.7,accel=tcg -cpu cortex-a15,pmu=on     NO     "No PMU property"
>     -M virt-2.6,accel=tcg -cpu cortex-a15            NO     NO
>     -M virt-2.6,accel=tcg -cpu cortex-a15,pmu=off    NO     "No PMU property"
>     -M virt-2.6,accel=tcg -cpu cortex-a15,pmu=on     NO     "No PMU property"
> 
>     * "NO KVM" msg
>       warning: pmu can't be enabled without KVM acceleration
>     * "No PMU property" msg
>       can't apply global cortex-a15-arm-cpu.pmu=off: Property '.pmu' not found
> 
> V3->V4:
>   * change has_pmu from Boolean to OnOffAuto to handle different cases
>   * "pmu" property is re-defined as DEFINE_PROP_ON_OFF_AUTO
> 
> V2->V3:
>   * revise patch 1 commit msg and if-else statement (Drew) 
>   * move property field into VirtMachineClass (Drew)
> 
> V1->V2:
>   * keep the original field name as "has_pmu"
>   * add a warning message when PMU is turned on without KVM
>   * use the feature bit to check PMU availability, instead of using has_pmu
>   * add PMU compat support to mach-virt machine type
> 
> RFC->V1:
>   * set default pmu=off
>   * change struct ARMCPU field name "has_pmu" ==> "has_host_pmu"
>   * like el3, add a new feature ARM_FEATURE_HOST_PMU
>   * "pmu" property becomes CPU dependent. Only cortex-a53/cortex-a57/host
>     running on kvm supports this option.
> 
> Thanks,
> -Wei
> 
> Wei Huang (2):
>   arm64: Add an option to turn on/off vPMU support
>   arm: virt: add PMU property to mach-virt machine type
> 
>  hw/arm/virt-acpi-build.c |  2 +-
>  hw/arm/virt.c            | 18 +++++++++++++++++-
>  target-arm/cpu.c         | 23 +++++++++++++++++++++++
>  target-arm/cpu.h         |  5 +++--
>  target-arm/cpu64.c       |  2 ++
>  target-arm/kvm64.c       | 17 ++++++++++++++---
>  6 files changed, 60 insertions(+), 7 deletions(-)
> 
> -- 
> 1.8.3.1
> 
> 



reply via email to

[Prev in Thread] Current Thread [Next in Thread]