From: Paolo Bonzini <pbonzini@redhat.com>
To: Yang Zhang <yang.z.zhang@intel.com>,
"Wu, Feng" <feng.wu@intel.com>,
Paolo Bonzini <pbonzini@redhat.com>,
KVM list <kvm@vger.kernel.org>
Cc: "iommu@lists.linux-foundation.org"
<iommu@lists.linux-foundation.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [v3 25/26] KVM: Suppress posted-interrupt when 'SN' is set
Date: Fri, 19 Dec 2014 13:00:37 +0100 [thread overview]
Message-ID: <54941365.60604@redhat.com> (raw)
In-Reply-To: <A9667DDFB95DB7438FA9D7D576C3D87E0AC050B1@SHSMSX104.ccr.corp.intel.com>
On 19/12/2014 06:25, Zhang, Yang Z wrote:
> I see your point. But from performance point, if we can schedule the
> vCPU to another PCPU to handle the interrupt, it would helpful. But I
> remember current KVM will not schedule the vCPU in run queue (even
> though it got preempted) to another pCPU to run(Am I right?). So it
> may hard to do it.
Yes. If the vCPU is in the run queue, it means it exhausted its
quantum. As Feng said, the scheduler can decide to migrate it to
another pCPU, or it can decide to leave it runnable but not start it.
KVM doesn't try to force the scheduler one way or the other.
If the vCPU is I/O bound, it will not exhaust its quantum and will not
be preempted. It will block, and the wakeup vector will restart it.
I don't think urgent notifications are interesting. If you want to do
real time work, pin the vCPU to a physical CPU, and isolate the pCPU
with isolcpus. Then the vCPU will always be running.
Paolo
next prev parent reply other threads:[~2014-12-19 12:00 UTC|newest]
Thread overview: 140+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-12-12 15:14 [v3 00/26] Add VT-d Posted-Interrupts support Feng Wu
2014-12-12 15:14 ` [v3 01/26] genirq: Introduce irq_set_vcpu_affinity() to target an interrupt to a VCPU Feng Wu
2014-12-12 15:14 ` [v3 02/26] iommu: Add new member capability to struct irq_remap_ops Feng Wu
2015-01-28 15:22 ` David Woodhouse
2015-01-29 8:34 ` Wu, Feng
2014-12-12 15:14 ` [v3 03/26] iommu, x86: Define new irte structure for VT-d Posted-Interrupts Feng Wu
2015-01-28 15:26 ` David Woodhouse
2014-12-12 15:14 ` [v3 04/26] iommu, x86: Implement irq_set_vcpu_affinity for intel_ir_chip Feng Wu
2015-01-28 15:26 ` David Woodhouse
2015-01-29 7:55 ` Wu, Feng
2014-12-12 15:14 ` [v3 05/26] x86, irq: Implement irq_set_vcpu_affinity for pci_msi_ir_controller Feng Wu
2014-12-12 15:14 ` [v3 06/26] iommu, x86: No need to migrating irq for VT-d Posted-Interrupts Feng Wu
2014-12-18 14:26 ` Zhang, Yang Z
2014-12-19 1:40 ` Wu, Feng
2014-12-19 1:46 ` Zhang, Yang Z
2014-12-19 11:59 ` Paolo Bonzini
2014-12-23 0:37 ` Zhang, Yang Z
2014-12-23 8:47 ` Paolo Bonzini
2014-12-23 9:07 ` Wu, Feng
2014-12-23 9:34 ` Paolo Bonzini
2014-12-24 1:38 ` Zhang, Yang Z
2014-12-24 2:12 ` Jiang Liu
2014-12-24 2:32 ` Zhang, Yang Z
2014-12-24 3:08 ` Wu, Feng
2014-12-24 4:04 ` Zhang, Yang Z
2014-12-24 4:54 ` Jiang Liu
2015-01-28 15:29 ` David Woodhouse
2014-12-12 15:14 ` [v3 07/26] iommu, x86: Add cap_pi_support() to detect VT-d PI capability Feng Wu
2015-01-28 15:32 ` David Woodhouse
2014-12-12 15:14 ` [v3 08/26] iommu, x86: Add intel_irq_remapping_capability() for Intel Feng Wu
2015-01-28 15:37 ` David Woodhouse
2015-01-29 8:57 ` Wu, Feng
2014-12-12 15:14 ` [v3 09/26] iommu, x86: define irq_remapping_cap() Feng Wu
2014-12-12 15:14 ` [v3 10/26] KVM: change struct pi_desc for VT-d Posted-Interrupts Feng Wu
2014-12-12 15:14 ` [v3 11/26] KVM: Add some helper functions for Posted-Interrupts Feng Wu
2014-12-12 15:14 ` [v3 12/26] KVM: Initialize VT-d Posted-Interrupts Descriptor Feng Wu
2014-12-18 15:19 ` Zhang, Yang Z
2014-12-12 15:14 ` [v3 13/26] KVM: Define a new interface kvm_find_dest_vcpu() for VT-d PI Feng Wu
2014-12-18 14:49 ` Zhang, Yang Z
2014-12-18 16:58 ` Paolo Bonzini
2014-12-19 1:13 ` Zhang, Yang Z
2014-12-19 1:30 ` Wu, Feng
2014-12-19 1:30 ` Wu, Feng
2014-12-19 1:47 ` Zhang, Yang Z
2014-12-19 11:59 ` Paolo Bonzini
2014-12-19 23:48 ` Wu, Feng
2014-12-20 13:16 ` Paolo Bonzini
2014-12-22 4:48 ` Wu, Feng
2014-12-22 9:27 ` Paolo Bonzini
2014-12-22 11:04 ` Wu, Feng
2014-12-22 11:06 ` Paolo Bonzini
2014-12-22 11:17 ` Wu, Feng
2014-12-22 11:23 ` Paolo Bonzini
2014-12-22 14:13 ` Yong Wang
2015-01-09 14:54 ` Radim Krčmář
2015-01-09 14:56 ` Paolo Bonzini
2015-01-09 15:12 ` Radim Krčmář
2015-01-09 15:18 ` Paolo Bonzini
2015-01-09 15:47 ` Radim Krčmář
2015-01-13 0:27 ` Wu, Feng
2015-01-13 16:17 ` Radim Kr?má?
2015-01-14 1:27 ` Wu, Feng
2015-01-14 13:02 ` Paolo Bonzini
2015-01-14 16:59 ` Radim Kr?má?
2015-01-20 21:04 ` Nadav Amit
2015-01-21 21:16 ` Radim Kr?má?
2014-12-12 15:14 ` [v3 14/26] KVM: Get Posted-Interrupts descriptor address from struct kvm_vcpu Feng Wu
2014-12-12 15:14 ` [v3 15/26] KVM: add interfaces to control PI outside vmx Feng Wu
2014-12-12 15:14 ` [v3 16/26] KVM: Make struct kvm_irq_routing_table accessible Feng Wu
2014-12-17 16:17 ` Paolo Bonzini
2014-12-19 2:19 ` Wu, Feng
2014-12-19 11:59 ` Paolo Bonzini
2014-12-19 23:39 ` Wu, Feng
2014-12-12 15:14 ` [v3 17/26] KVM: make kvm_set_msi_irq() public Feng Wu
2014-12-17 17:32 ` Paolo Bonzini
2014-12-12 15:14 ` [v3 18/26] KVM: kvm-vfio: User API for VT-d Posted-Interrupts Feng Wu
2014-12-12 15:14 ` [v3 19/26] KVM: kvm-vfio: implement the VFIO skeleton " Feng Wu
2014-12-12 15:14 ` [v3 20/26] KVM: x86: kvm-vfio: VT-d posted-interrupts setup Feng Wu
2014-12-12 15:14 ` [v3 21/26] x86, irq: Define a global vector for VT-d Posted-Interrupts Feng Wu
2014-12-18 14:54 ` Zhang, Yang Z
2014-12-19 0:52 ` Wu, Feng
2015-01-30 18:18 ` H. Peter Anvin
2015-02-02 1:06 ` Wu, Feng
2015-02-23 22:04 ` Marcelo Tosatti
2014-12-12 15:14 ` [v3 22/26] KVM: Define a wakeup worker thread for vCPU Feng Wu
2014-12-12 15:14 ` [v3 23/26] KVM: Update Posted-Interrupts Descriptor when vCPU is preempted Feng Wu
2014-12-17 17:11 ` Paolo Bonzini
2014-12-18 3:15 ` Wu, Feng
2014-12-18 8:32 ` Paolo Bonzini
2014-12-19 2:09 ` Wu, Feng
2015-02-23 22:21 ` Marcelo Tosatti
2015-03-02 9:12 ` Wu, Feng
2014-12-12 15:14 ` [v3 24/26] KVM: Update Posted-Interrupts Descriptor when vCPU is blocked Feng Wu
2014-12-17 17:09 ` Paolo Bonzini
2014-12-18 3:16 ` Wu, Feng
2014-12-18 8:37 ` Paolo Bonzini
2014-12-19 2:51 ` Wu, Feng
2015-02-25 21:50 ` Marcelo Tosatti
2015-02-26 8:08 ` Wu, Feng
2015-02-26 23:41 ` Marcelo Tosatti
2015-02-26 23:40 ` Marcelo Tosatti
2015-03-02 13:36 ` Wu, Feng
2015-03-04 12:06 ` Marcelo Tosatti
2015-03-06 6:51 ` Wu, Feng
2015-03-12 1:15 ` Marcelo Tosatti
2015-03-16 11:42 ` Wu, Feng
2015-03-25 23:17 ` Marcelo Tosatti
2015-03-27 6:34 ` Wu, Feng
2015-03-27 19:30 ` Marcelo Tosatti
2015-03-30 4:46 ` Wu, Feng
2015-03-30 23:55 ` Marcelo Tosatti
2015-03-31 1:13 ` Wu, Feng
2015-04-14 7:37 ` Wu, Feng
2015-06-05 21:59 ` Marcelo Tosatti
2015-06-08 1:43 ` Wu, Feng
2014-12-12 15:14 ` [v3 25/26] KVM: Suppress posted-interrupt when 'SN' is set Feng Wu
2014-12-17 17:42 ` Paolo Bonzini
2014-12-18 3:14 ` Wu, Feng
2014-12-18 8:38 ` Paolo Bonzini
2014-12-18 15:09 ` Zhang, Yang Z
2014-12-19 2:58 ` Wu, Feng
2014-12-19 3:32 ` Zhang, Yang Z
2014-12-19 4:34 ` Wu, Feng
2014-12-19 4:44 ` Zhang, Yang Z
2014-12-19 4:49 ` Wu, Feng
2014-12-19 5:25 ` Zhang, Yang Z
2014-12-19 5:46 ` Wu, Feng
2014-12-19 7:04 ` Zhang, Yang Z
2014-12-19 12:00 ` Paolo Bonzini [this message]
2014-12-19 23:34 ` Wu, Feng
2014-12-12 15:15 ` [v3 26/26] iommu/vt-d: Add a command line parameter for VT-d posted-interrupts Feng Wu
2015-01-28 15:39 ` David Woodhouse
2014-12-16 9:04 ` [v3 00/26] Add VT-d Posted-Interrupts support Wu, Feng
2015-01-06 1:10 ` Wu, Feng
2015-01-09 12:46 ` joro
2015-01-09 13:58 ` Wu, Feng
2015-01-21 2:25 ` Wu, Feng
2015-01-28 3:01 ` Wu, Feng
2015-01-28 3:44 ` Alex Williamson
2015-01-28 4:44 ` Wu, Feng
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