On Tue, Mar 9, 2021 at 6:05 PM Sean Christopherson wrote:
>
> On Tue, Mar 09, 2021, Peter Zijlstra wrote:
> > On Tue, Mar 09, 2021 at 08:46:49AM +0100, Peter Zijlstra wrote:
> > > On Mon, Mar 08, 2021 at 12:40:44PM -0800, Sean Christopherson wrote:
> > > > On Mon, Mar 08, 2021, Peter Zijlstra wrot
On Tue, Mar 09, 2021, Peter Zijlstra wrote:
> On Tue, Mar 09, 2021 at 08:46:49AM +0100, Peter Zijlstra wrote:
> > On Mon, Mar 08, 2021 at 12:40:44PM -0800, Sean Christopherson wrote:
> > > On Mon, Mar 08, 2021, Peter Zijlstra wrote:
> >
> > > > Given the one user in atomic_switch_perf_msrs() that
On Tue, Mar 09, 2021 at 08:46:49AM +0100, Peter Zijlstra wrote:
> On Mon, Mar 08, 2021 at 12:40:44PM -0800, Sean Christopherson wrote:
> > On Mon, Mar 08, 2021, Peter Zijlstra wrote:
>
> > > Given the one user in atomic_switch_perf_msrs() that should work because
> > > it doesn't seem to care abou
On Mon, Mar 08, 2021 at 12:40:44PM -0800, Sean Christopherson wrote:
> On Mon, Mar 08, 2021, Peter Zijlstra wrote:
> > Given the one user in atomic_switch_perf_msrs() that should work because
> > it doesn't seem to care about nr_msrs when !msrs.
>
> Uh, that commit quite cleary says:
D0h! I got
On Mon, Mar 08, 2021, Peter Zijlstra wrote:
> On Mon, Mar 08, 2021 at 10:25:59AM +0800, Xu, Like wrote:
> > On 2021/3/6 6:33, Sean Christopherson wrote:
> > > Handle a NULL x86_pmu.guest_get_msrs at invocation instead of patching
> > > in perf_guest_get_msrs_nop() during setup. If there is no PMU,
On 2021/3/8 16:53, Peter Zijlstra wrote:
Still, it calling atomic_switch_perf_msrs() and
intel_pmu_lbr_is_enabled() when there isn't a PMU at all is of course, a
complete waste of cycles.
This suggestion is reminiscent of a sad regression of optimizing it:
https://lore.kernel.org/kvm/202006190
On Mon, Mar 08, 2021 at 10:25:59AM +0800, Xu, Like wrote:
> On 2021/3/6 6:33, Sean Christopherson wrote:
> > Handle a NULL x86_pmu.guest_get_msrs at invocation instead of patching
> > in perf_guest_get_msrs_nop() during setup. If there is no PMU, setup
>
> "If there is no PMU" ...
Then you shoul
On Mon, Mar 8, 2021 at 9:35 AM Like Xu wrote:
>
> On 2021/3/8 15:12, Dmitry Vyukov wrote:
> > On Mon, Mar 8, 2021 at 3:26 AM Xu, Like wrote:
> >>
> >> On 2021/3/6 6:33, Sean Christopherson wrote:
> >>> Handle a NULL x86_pmu.guest_get_msrs at invocation instead of patching
> >>> in perf_guest_get_
On 2021/3/8 15:12, Dmitry Vyukov wrote:
On Mon, Mar 8, 2021 at 3:26 AM Xu, Like wrote:
On 2021/3/6 6:33, Sean Christopherson wrote:
Handle a NULL x86_pmu.guest_get_msrs at invocation instead of patching
in perf_guest_get_msrs_nop() during setup. If there is no PMU, setup
"If there is no PM
On Mon, Mar 8, 2021 at 3:26 AM Xu, Like wrote:
>
> On 2021/3/6 6:33, Sean Christopherson wrote:
> > Handle a NULL x86_pmu.guest_get_msrs at invocation instead of patching
> > in perf_guest_get_msrs_nop() during setup. If there is no PMU, setup
>
> "If there is no PMU" ...
>
> How to set up this k
On 2021/3/6 6:33, Sean Christopherson wrote:
Handle a NULL x86_pmu.guest_get_msrs at invocation instead of patching
in perf_guest_get_msrs_nop() during setup. If there is no PMU, setup
"If there is no PMU" ...
How to set up this kind of environment,
and what changes are needed in .config or b
Handle a NULL x86_pmu.guest_get_msrs at invocation instead of patching
in perf_guest_get_msrs_nop() during setup. If there is no PMU, setup
bails before updating the static calls, leaving x86_pmu.guest_get_msrs
NULL and thus a complete nop. Ultimately, this causes VMX abort on
VM-Exit due to KVM
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