Pass-through network interface controller configured to support latency sensitive virtual machines

Patent metadata

Field	Value
Publication number	US-9552216-B2
Application number	US-201414468138-A
Country	US
Kind code	B2
Filing date	Aug 25, 2014
Priority date	Aug 26, 2013
Publication date	Jan 24, 2017
Grant date	Jan 24, 2017

Abstract

A host computer has a plurality of virtual machines executing therein under the control of a hypervisor, where the host also includes a physical network interface controller (NIC). An interrupt controller detects an interrupt generated by the physical NIC, where the interrupt corresponds to a virtual machine. If the virtual machine has exclusive affinity to one or more physical central processing units (CPUs), then the interrupt is forwarded to the virtual machine. If the virtual machine does not have exclusive affinity, then a process in the hypervisor is invoked to forward the interrupt to the virtual machine.

First claim

We claim:

1. In a host computer having a plurality of virtual machines executing therein under the control of a hypervisor, the host including a physical network interface controller (NIC), a method of processing interrupts from the physical NIC, the method being performed by the host computer and comprising:
detecting an interrupt generated by the physical NIC upon reception of a packet by the physical NIC;
determining a virtual machine to which the interrupt corresponds;
determining, by the hypervisor, whether the virtual machine has exclusive affinity to a physical central processing unit (CPU);
if the virtual machine has exclusive affinity to a physical CPU, then forwarding the interrupt to the virtual machine; and
if the virtual machine does not have exclusive affinity to a physical CPU, then invoking a process in the hypervisor to forward the interrupt to the virtual machine.

2. The method of claim 1 , wherein the physical NIC is configured to operate in a passthrough mode that enables transmission of packets between the physical NIC and a virtual machine, wherein the packets are not forwarded between the physical NIC and the virtual machine by the hypervisor.

3. The method of claim 2 , wherein the physical NIC includes a plurality of ports, each port configured to receive packets corresponding to one of the virtual machines.

4. The method of claim 1 , further comprising:
after determining, by the hypervisor, whether the virtual machine has exclusive affinity to a physical CPU, wherein the determining comprises:
reading an exclusive affinity indicator for the virtual machine; and
determining whether the exclusive affinity indicator is a predetermined value,

programming an interrupt controller based on the determining.

5. The method of claim 4 , wherein, if the virtual machine has exclusive affinity, then the forwarding of the interrupt comprises:
determining, by the interrupt controller, a first physical CPU, wherein a virtual CPU of the virtual machine has exclusive affinity to the first physical CPU; and
posting, by the interrupt controller, the interrupt to the first physical CPU.

6. The method of claim 4 , further comprising, if the virtual machine does not have exclusive affinity, then posting the interrupt, by the interrupt controller, to a second physical CPU that is different from the first physical CPU.

7. The method of claim 6 , wherein no virtual CPU has exclusive affinity to the second physical CPU.

8. A non-transitory computer-readable medium comprising instructions executable by a host computer, the host computer having a plurality of virtual machines executing therein under the control of a hypervisor, and the host including a physical network interface controller (NIC), where the instructions, when executed, cause the host computer to perform a method of processing interrupts from the physical NIC, the method comprising:
detecting an interrupt generated by the physical NIC upon reception of a packet by the physical NIC;
determining a virtual machine to which the interrupt corresponds;
determining, by the hypervisor, whether the virtual machine has exclusive affinity to a physical central processing unit (CPU);
if the virtual machine has exclusive affinity to a physical CPU, then forwarding the interrupt to the virtual machine; and
if the virtual machine does not have exclusive affinity to a physical CPU, then invoking a process in the hypervisor to forward the interrupt to the virtual machine.

9. The computer-readable medium of claim 8 , wherein the physical NIC is configured to operate in a passthrough mode that enables transmission of packets between the physical NIC and a virtual machine, wherein the packets are not forwarded between the physical NIC and the virtual machine by the hypervisor.

10. The computer-readable medium of claim 9 , wherein the physical NIC includes a plurality of ports, each port configured to receive packets corresponding to one of the virtual machines.

11. The computer-readable medium of claim 8 , wherein the method further comprises:
after determining, by the hypervisor, whether the virtual machine has exclusive affinity to a physical CPU, wherein the determining comprises:
reading an exclusive affinity indicator for the virtual machine; and
determining whether the exclusive affinity indicator is a predetermined value,

programming an interrupt controller based on the determining.

12. The computer-readable medium of claim 11 , wherein, if the virtual machine has exclusive affinity, then said forwarding of the interrupt comprises:
determining, by the interrupt controller, a first physical CPU, wherein a virtual CPU of the virtual machine has exclusive affinity to the first physical CPU; and
posting, by the interrupt controller, the interrupt to the first physical CPU.

13. The computer-readable medium of claim 11 , further comprising, if the virtual machine does not have exclusive affinity, then posting the interrupt, by the interrupt controller, to a second physical CPU that is different from the first physical CPU.

14. The computer-readable medium of claim 13 , wherein no virtual CPU has exclusive affinity to the second physical CPU.

15. A virtualized computing system, comprising:
a host computer, the host computer having a plurality of virtual machines executing therein under the control of a hypervisor;
a physical network interface controller (NIC); and
an interrupt controller, wherein the hypervisor and interrupt controller are configured to perform a method of processing interrupts from the physical NIC, the method comprising:
detecting an interrupt generated by the physical NIC upon reception of a packet by the physical NIC;
determining a virtual machine to which the interrupt corresponds;
determining, by the hypervisor, whether the virtual machine has exclusive affinity to a physical central processing unit (CPU);
if the virtual machine has exclusive affinity to a physical CPU, then forwarding the interrupt to the virtual machine; and
if the virtual machine does not have exclusive affinity, then invoking a process in the hypervisor to forward the interrupt to the virtual machine.

16. The system of claim 15 , wherein the physical NIC is configured to operate in a passthrough mode that enables transmission of packets between the physical NIC and a virtual machine, wherein the packets are not forwarded between the physical NIC and the virtual machine by the hypervisor.

17. The system of claim 16 , wherein the physical NIC includes a plurality of ports, each port configured to receive packets corresponding to one of the virtual machines.

18. The system of claim 15 , wherein the method further comprises:
after determining, by the hypervisor, whether the virtual machine has exclusive affinity to a physical CPU, wherein the determining comprises:
reading an exclusive affinity indicator for the virtual machine; and
determining whether the exclusive affinity indicator is a predetermined value,

programming an interrupt controller based on the determining.

19. The system of claim 18 , wherein, if the virtual machine has exclusive affinity, then said forwarding of the interrupt comprises:
determining, by the interrupt controller, a first physical CPU to which a virtual CPU of the virtual machine has exclusive affinity; and
posting, by the interrupt controller, the interrupt to the first physical CPU.

20. The system of claim 18 , wherein the method further comprises, if the virtual machine does not have exclusive affini

Assignees

• Vmware Inc

Inventors

• Zheng Haoqiang
• Singaravelu Lenin
• Agarwal Shilpi
• Hecht Daniel Michael
• Smith Garrett

Classifications

• G06F2009/45575

  Starting, stopping, suspending or resuming virtual machine instances · CPC title

• H04L43/16

  Threshold monitoring · CPC title

• G06F9/4812

  by interrupt, e.g. masked · CPC title

• G06F13/24

  using interrupt (G06F13/32 takes precedence) · CPC title

• H04L47/801

  Real time traffic · CPC title