Commit 920552b2 authored by David Hildenbrand's avatar David Hildenbrand Committed by Paolo Bonzini
Browse files

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: default avatarDavid Hildenbrand <dahi@linux.vnet.ibm.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent 58c95070
......@@ -33,6 +33,7 @@
#define KVM_PRIVATE_MEM_SLOTS 4
#define KVM_COALESCED_MMIO_PAGE_OFFSET 1
#define KVM_HAVE_ONE_REG
#define KVM_HALT_POLL_NS_DEFAULT 500000
#define KVM_VCPU_MAX_FEATURES 2
......
......@@ -33,6 +33,7 @@
#define KVM_USER_MEM_SLOTS 32
#define KVM_PRIVATE_MEM_SLOTS 4
#define KVM_COALESCED_MMIO_PAGE_OFFSET 1
#define KVM_HALT_POLL_NS_DEFAULT 500000
#include <kvm/arm_vgic.h>
#include <kvm/arm_arch_timer.h>
......
......@@ -61,6 +61,7 @@
#define KVM_PRIVATE_MEM_SLOTS 0
#define KVM_COALESCED_MMIO_PAGE_OFFSET 1
#define KVM_HALT_POLL_NS_DEFAULT 500000
......
......@@ -44,6 +44,7 @@
#ifdef CONFIG_KVM_MMIO
#define KVM_COALESCED_MMIO_PAGE_OFFSET 1
#endif
#define KVM_HALT_POLL_NS_DEFAULT 500000
/* These values are internal and can be increased later */
#define KVM_NR_IRQCHIPS 1
......
......@@ -35,6 +35,7 @@
*/
#define KVM_NR_IRQCHIPS 1
#define KVM_IRQCHIP_NUM_PINS 4096
#define KVM_HALT_POLL_NS_DEFAULT 0
#define SIGP_CTRL_C 0x80
#define SIGP_CTRL_SCN_MASK 0x3f
......
......@@ -40,6 +40,7 @@
#define KVM_PIO_PAGE_OFFSET 1
#define KVM_COALESCED_MMIO_PAGE_OFFSET 2
#define KVM_HALT_POLL_NS_DEFAULT 500000
#define KVM_IRQCHIP_NUM_PINS KVM_IOAPIC_NUM_PINS
......
......@@ -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. */
......
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