From: Marcelo Tosatti <mtosatti@redhat.com>
To: kvm@vger.kernel.org
Cc: johnstul@us.ibm.com, jeremy@goop.org, glommer@parallels.com,
zamsden@gmail.com, gleb@redhat.com, avi@redhat.com,
pbonzini@redhat.com, Marcelo Tosatti <mtosatti@redhat.com>
Subject: [patch 18/18] KVM: x86: update pvclock area conditionally, on cpu migration
Date: Wed, 14 Nov 2012 22:08:41 -0200 [thread overview]
Message-ID: <20121115000944.772253863@redhat.com> (raw)
In-Reply-To: 20121115000823.285102321@redhat.com
[-- Attachment #1: 18-do-not-writeclock-on-cpu-migration --]
[-- Type: text/plain, Size: 886 bytes --]
As requested by Glauber, do not update kvmclock area on vcpu->pcpu
migration, in case the host has stable TSC.
This is to reduce cacheline bouncing.
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Index: vsyscall/arch/x86/kvm/x86.c
===================================================================
--- vsyscall.orig/arch/x86/kvm/x86.c
+++ vsyscall/arch/x86/kvm/x86.c
@@ -2615,7 +2615,12 @@ void kvm_arch_vcpu_load(struct kvm_vcpu
kvm_x86_ops->write_tsc_offset(vcpu, offset);
vcpu->arch.tsc_catchup = 1;
}
- kvm_make_request(KVM_REQ_CLOCK_UPDATE, vcpu);
+ /*
+ * On a host with synchronized TSC, there is no need to update
+ * kvmclock on vcpu->cpu migration
+ */
+ if (!vcpu->kvm->arch.use_master_clock || vcpu->cpu == -1)
+ kvm_make_request(KVM_REQ_CLOCK_UPDATE, vcpu);
if (vcpu->cpu != cpu)
kvm_migrate_timers(vcpu);
vcpu->cpu = cpu;
next prev parent reply other threads:[~2012-11-15 1:33 UTC|newest]
Thread overview: 49+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-11-15 0:08 [patch 00/18] pvclock vsyscall support + KVM hypervisor support (v4) Marcelo Tosatti
2012-11-15 0:08 ` [patch 01/18] KVM: x86: retain pvclock guest stopped bit in guest memory Marcelo Tosatti
2012-11-15 0:08 ` [patch 02/18] x86: kvmclock: allocate pvclock shared memory area Marcelo Tosatti
2012-11-15 17:05 ` Glauber Costa
2012-11-16 2:07 ` [patch 02/18] x86: kvmclock: allocate pvclock shared memory area (v2) Marcelo Tosatti
2012-11-16 7:06 ` Glauber Costa
2012-11-15 0:08 ` [patch 03/18] x86: pvclock: make sure rdtsc doesnt speculate out of region Marcelo Tosatti
2012-11-15 0:08 ` [patch 04/18] x86: pvclock: remove pvclock_shadow_time Marcelo Tosatti
2012-11-15 0:08 ` [patch 05/18] x86: pvclock: create helper for pvclock data retrieval Marcelo Tosatti
2012-11-15 12:27 ` Glauber Costa
2012-11-15 0:08 ` [patch 06/18] x86: pvclock: introduce helper to read flags Marcelo Tosatti
2012-11-15 12:28 ` Glauber Costa
2012-11-15 0:08 ` [patch 07/18] x86: pvclock: add note about rdtsc barriers Marcelo Tosatti
2012-11-15 12:30 ` Glauber Costa
2012-11-16 2:05 ` [patch 07/18] x86: pvclock: add note about rdtsc barriers (v2) Marcelo Tosatti
2012-11-15 0:08 ` [patch 08/18] sched: add notifier for cross-cpu migrations Marcelo Tosatti
2012-11-15 7:01 ` Gleb Natapov
2012-11-15 0:08 ` [patch 09/18] x86: pvclock: generic pvclock vsyscall initialization Marcelo Tosatti
2012-11-15 0:08 ` [patch 10/18] x86: kvm guest: pvclock vsyscall support Marcelo Tosatti
2012-11-15 0:08 ` [patch 11/18] x86: vdso: pvclock gettime support Marcelo Tosatti
2012-11-15 0:08 ` [patch 12/18] KVM: x86: pass host_tsc to read_l1_tsc Marcelo Tosatti
2012-11-15 0:08 ` [patch 13/18] time: export time information for KVM pvclock Marcelo Tosatti
2012-11-15 1:38 ` John Stultz
2012-11-15 0:08 ` [patch 14/18] KVM: x86: notifier for clocksource changes Marcelo Tosatti
2012-11-15 0:08 ` [patch 15/18] KVM: x86: implement PVCLOCK_TSC_STABLE_BIT pvclock flag Marcelo Tosatti
2012-11-15 0:08 ` [patch 16/18] KVM: x86: add kvm_arch_vcpu_postcreate callback, move TSC initialization Marcelo Tosatti
2012-11-15 0:08 ` [patch 17/18] KVM: x86: require matched TSC offsets for master clock Marcelo Tosatti
2012-11-15 0:08 ` Marcelo Tosatti [this message]
2012-11-15 12:34 ` [patch 18/18] KVM: x86: update pvclock area conditionally, on cpu migration Glauber Costa
2012-11-19 21:57 ` [patch 00/18] pvclock vsyscall support + KVM hypervisor support (v5) Marcelo Tosatti
2012-11-19 21:57 ` [patch 01/18] KVM: x86: retain pvclock guest stopped bit in guest memory Marcelo Tosatti
2012-11-19 21:58 ` [patch 02/18] x86: kvmclock: allocate pvclock shared memory area Marcelo Tosatti
2012-11-19 21:58 ` [patch 03/18] x86: pvclock: make sure rdtsc doesnt speculate out of region Marcelo Tosatti
2012-11-19 21:58 ` [patch 04/18] x86: pvclock: remove pvclock_shadow_time Marcelo Tosatti
2012-11-19 21:58 ` [patch 05/18] x86: pvclock: create helper for pvclock data retrieval Marcelo Tosatti
2012-11-19 21:58 ` [patch 06/18] x86: pvclock: introduce helper to read flags Marcelo Tosatti
2012-11-19 21:58 ` [patch 07/18] x86: pvclock: add note about rdtsc barriers Marcelo Tosatti
2012-11-19 21:58 ` [patch 08/18] sched: add notifier for cross-cpu migrations Marcelo Tosatti
2012-11-19 21:58 ` [patch 09/18] x86: pvclock: generic pvclock vsyscall initialization Marcelo Tosatti
2012-11-19 21:58 ` [patch 11/18] x86: vdso: pvclock gettime support Marcelo Tosatti
2012-11-19 21:58 ` [patch 12/18] KVM: x86: pass host_tsc to read_l1_tsc Marcelo Tosatti
2012-11-19 21:58 ` [patch 13/18] time: export time information for KVM pvclock Marcelo Tosatti
2012-11-19 21:58 ` [patch 14/18] KVM: x86: notifier for clocksource changes Marcelo Tosatti
2012-11-19 21:58 ` [patch 15/18] KVM: x86: implement PVCLOCK_TSC_STABLE_BIT pvclock flag Marcelo Tosatti
2012-11-19 21:58 ` [patch 16/18] KVM: x86: add kvm_arch_vcpu_postcreate callback, move TSC initialization Marcelo Tosatti
2012-11-19 21:58 ` [patch 17/18] KVM: x86: require matched TSC offsets for master clock Marcelo Tosatti
2012-11-19 21:58 ` [patch 18/18] KVM: x86: update pvclock area conditionally, on cpu migration Marcelo Tosatti
2012-11-20 9:01 ` Glauber Costa
2012-11-20 9:03 ` [patch 00/18] pvclock vsyscall support + KVM hypervisor support (v5) Glauber Costa
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