v2:
* move request_exits debug counter patch right after introduction of
KVM_REQ_EXIT [3/5]
* use vcpu ioctl instead of vm one [4/5]
* shrink kvm_user_exit from 64 to 32 bytes [4/5]
* new [5/5]
QEMU uses SIGUSR1 to force a userspace exit and also to queue an early
exit before calling VCPU_RUN -- the signal is blocked in user space and
temporarily unblocked in VCPU_RUN.
The temporal unblocking by sigprocmask() in kvm_arch_vcpu_ioctl_run()
takes a shared siglock, which leads to cacheline bouncing in NUMA
systems.
This series allows the same with a new request bit and VM IOCTL that
marks and kicks target VCPU, hence no need to unblock.
inl_from_{pmtimer,qemu} vmexit benchmark from kvm-unit-tests shows ~5%
speedup for 1-4 VCPUs (300-2000 saved cycles) without noticeably
regressing kernel VM exits.
(Paolo did a quick run of older version of this series on a NUMA system
and the speedup was around 35% when utilizing more nodes.)
Radim Krčmář (5):
KVM: add kvm_has_request wrapper
KVM: add KVM_REQ_EXIT request for userspace exit
KVM: x86: add request_exits debug counter
KVM: add KVM_USER_EXIT vcpu ioctl for userspace exit
KVM: refactor asynchronous vcpu ioctl dispatch
Documentation/virtual/kvm/api.txt | 30 ++++++++++++++++++++++++++++++
arch/x86/include/asm/kvm_host.h | 1 +
arch/x86/kvm/vmx.c | 4 ++--
arch/x86/kvm/x86.c | 32 ++++++++++++++++++++++++++++++++
include/linux/kvm_host.h | 15 +++++++++++++--
include/uapi/linux/kvm.h | 8 ++++++++
virt/kvm/kvm_main.c | 14 +++++++++-----
7 files changed, 95 insertions(+), 9 deletions(-)
--
2.5.0
--
To unsubscribe from this list: send the line "unsubscribe kvm" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
