[PATCH v3 0/3] KVM: Dynamic halt_poll_ns

From: Wanpeng Li
Date: Wed Aug 26 2015 - 05:14:49 EST


v2 -> v3:
* grow/shrink vcpu->halt_poll_ns by *halt_poll_ns_grow or /halt_poll_ns_shrink
* drop the macros and hard coding the numbers in the param definitions
* update the comments "5-7 us"
* remove halt_poll_ns_max and use halt_poll_ns as the max halt_poll_ns time,
vcpu->halt_poll_ns start at zero
* drop the wrappers
* move the grow/shrink logic before "out:" w/ "if (waited)"

v1 -> v2:
* change kvm_vcpu_block to read halt_poll_ns from the vcpu instead of
the module parameter
* use the shrink/grow matrix which is suggested by David
* set halt_poll_ns_max to 2ms

There is a downside of halt_poll_ns since poll is still happen for idle
VCPU which can waste cpu usage. This patchset add the ability to adjust
halt_poll_ns dynamically.

There are two new kernel parameters for changing the halt_poll_ns:
halt_poll_ns_grow and halt_poll_ns_shrink. The shrink/grow matrix is
suggested by David:

if (poll successfully for interrupt): stay the same
else if (length of kvm_vcpu_block is longer than halt_poll_ns_max): shrink
else if (length of kvm_vcpu_block is less than halt_poll_ns_max): grow

Wanpeng Li (3):
KVM: make halt_poll_ns per-VCPU
KVM: dynamic halt_poll_ns adjustment
KVM: trace kvm_halt_poll_ns grow/shrink

include/linux/kvm_host.h | 1 +
include/trace/events/kvm.h | 30 ++++++++++++++++++++++++++
virt/kvm/kvm_main.c | 52 +++++++++++++++++++++++++++++++++++++++++++---
3 files changed, 80 insertions(+), 3 deletions(-)

--
1.9.1

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