From: Christian Borntraeger <borntraeger@de.ibm.com>
Date: Wed, 15 May 2019 07:59:08 +0000 (+0200)
Subject: KVM: s390: change default halt poll time to 50us
X-Git-Tag: v5.4.17~3471^2~29^2
X-Git-Url: http://xenbits.xensource.com/gitweb?a=commitdiff_plain;h=6e9b622d1c3628fae65217465a148b157a361c2a;p=people%2Faperard%2Flinux.git

KVM: s390: change default halt poll time to 50us

Recent measurements indicate that using 50us results in a reduced CPU
consumption, while still providing the benefit of halt polling. Let's
use 50us instead.

Acked-by: David Hildenbrand <david@redhat.com>
Acked-by: Janosch Frank <frankja@linux.ibm.com>
Acked-by: Cornelia Huck <cohuck@redhat.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
---

diff --git a/arch/s390/include/asm/kvm_host.h b/arch/s390/include/asm/kvm_host.h
index bdbc81b5bc914..2b00a3ebee086 100644
--- a/arch/s390/include/asm/kvm_host.h
+++ b/arch/s390/include/asm/kvm_host.h
@@ -36,7 +36,7 @@
  */
 #define KVM_NR_IRQCHIPS 1
 #define KVM_IRQCHIP_NUM_PINS 4096
-#define KVM_HALT_POLL_NS_DEFAULT 80000
+#define KVM_HALT_POLL_NS_DEFAULT 50000
 
 /* s390-specific vcpu->requests bit members */
 #define KVM_REQ_ENABLE_IBS	KVM_ARCH_REQ(0)