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authorDavid Hildenbrand <dahi@linux.vnet.ibm.com>2015-09-18 12:34:53 +0200
committerPaolo Bonzini <pbonzini@redhat.com>2015-09-25 10:31:30 +0200
commit920552b213e3dc832a874b4e7ba29ecddbab31bc (patch)
treec07ed91961b7842a5056f98794c4827a0e493cea /virt
parent58c95070da3a504fbeca7939435bbb062cb96ea3 (diff)
downloadlinux-sh-920552b213e3dc832a874b4e7ba29ecddbab31bc.tar.gz
KVM: disable halt_poll_ns as default for s390x
We observed some performance degradation on s390x with dynamic halt polling. Until we can provide a proper fix, let's enable halt_poll_ns as default only for supported architectures. Architectures are now free to set their own halt_poll_ns default value. Signed-off-by: David Hildenbrand <dahi@linux.vnet.ibm.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'virt')
-rw-r--r--virt/kvm/kvm_main.c4
1 files changed, 2 insertions, 2 deletions
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 04146a2e1d81..8db1d9361993 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -66,8 +66,8 @@
MODULE_AUTHOR("Qumranet");
MODULE_LICENSE("GPL");
-/* halt polling only reduces halt latency by 5-7 us, 500us is enough */
-static unsigned int halt_poll_ns = 500000;
+/* Architectures should define their poll value according to the halt latency */
+static unsigned int halt_poll_ns = KVM_HALT_POLL_NS_DEFAULT;
module_param(halt_poll_ns, uint, S_IRUGO | S_IWUSR);
/* Default doubles per-vcpu halt_poll_ns. */