2016-05-24 14:59 GMT+08:00 Christian Borntraeger <borntraeger@xxxxxxxxxx>:
> On 05/24/2016 04:25 AM, Wanpeng Li wrote:
>> 2016-05-24 10:19 GMT+08:00 Wanpeng Li <kernellwp@xxxxxxxxx>:
>>> 2016-05-24 2:01 GMT+08:00 David Matlack <dmatlack@xxxxxxxxxx>:
>>>> On Sun, May 22, 2016 at 5:42 PM, Wanpeng Li <kernellwp@xxxxxxxxx> wrote:
>>>>> From: Wanpeng Li <wanpeng.li@xxxxxxxxxxx>
>>>>
>>>> I'm ok with this patch, but I'd like to better understand the target
>>>> workloads. What type of workloads do you expect to benefit from this?
>>>
>>> dynticks guests I think is one of workloads which can get benefit,
>>> there are lots of upcoming fire timers captured by my feature. Even
>>> during TCP testing. And also the workload of Yang's.
>>
>> Do you think I should add an module parameter to enable/disable it
>> during module insmod or current patch is fine?
>
> What about getting rid of this hunk
>
> - val = 10000;
> + val = halt_poll_ns_base;
>
>
> and then rename "halt_poll_ns_base" into "halt_poll_ns_timer" that
> can be changed as module parameter?
Good point,
>
>
> I also experimented with an s390 implementation, which seems pretty straightforward.
> It is probably something like the following (whitespace damaged due to pcopy/paste)
> and needs more testing.
>
> diff --git a/arch/s390/include/asm/kvm_host.h b/arch/s390/include/asm/kvm_host.h
> index 38bbc98..a97739d 100644
> --- a/arch/s390/include/asm/kvm_host.h
> +++ b/arch/s390/include/asm/kvm_host.h
> @@ -682,6 +682,7 @@ void kvm_arch_async_page_present(struct kvm_vcpu *vcpu,
> struct kvm_async_pf *work);
>
> extern int sie64a(struct kvm_s390_sie_block *, u64 *);
> +extern u64 kvm_s390_timer_remaining(struct kvm_vcpu *vcpu);
> extern char sie_exit;
>
> static inline void kvm_arch_hardware_disable(void) {}
> @@ -699,7 +700,7 @@ static inline void kvm_arch_vcpu_blocking(struct kvm_vcpu *vcpu) {}
> static inline void kvm_arch_vcpu_unblocking(struct kvm_vcpu *vcpu) {}
> static inline u64 kvm_arch_timer_remaining(struct kvm_vcpu *vcpu)
> {
> - return -1ULL;
> + return kvm_s390_timer_remaining(vcpu);
> }
>
> void kvm_arch_vcpu_block_finish(struct kvm_vcpu *vcpu);
> diff --git a/arch/s390/kvm/interrupt.c b/arch/s390/kvm/interrupt.c
> index 5a80af7..5b209a2 100644
> --- a/arch/s390/kvm/interrupt.c
> +++ b/arch/s390/kvm/interrupt.c
> @@ -936,6 +936,17 @@ static u64 __calculate_sltime(struct kvm_vcpu *vcpu)
> return sltime;
> }
>
> +
> +u64 kvm_s390_timer_remaining(struct kvm_vcpu *vcpu)
> +{
> + u64 result;
> +
> + preempt_disable();
> + result = __calculate_sltime(vcpu);
> + preempt_enable();
> + return result;
> +}
> +
> int kvm_s390_handle_wait(struct kvm_vcpu *vcpu)
> {
> u64 sltime;
>
--
Regards,
Wanpeng Li
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