From: Wanpeng Li <kernellwp@gmail.com>
To: linux-kernel@vger.kernel.org, kvm@vger.kernel.org
Cc: "Paolo Bonzini" <pbonzini@redhat.com>,
"Radim Krčmář" <rkrcmar@redhat.com>,
"Christian Borntraeger" <borntraeger@de.ibm.com>
Subject: [PATCH] KVM: Boosting vCPUs that are delivering interrupts
Date: Fri, 12 Jul 2019 15:10:35 +0800 [thread overview]
Message-ID: <1562915435-8818-1-git-send-email-wanpengli@tencent.com> (raw)
From: Wanpeng Li <wanpengli@tencent.com>
Inspired by commit 9cac38dd5d (KVM/s390: Set preempted flag during vcpu wakeup
and interrupt delivery), except the lock holder, we want to also boost vCPUs
that are delivering interrupts. Actually most smp_call_function_many calls are
synchronous ipi calls, the ipi target vCPUs are also good yield candidates.
This patch sets preempted flag during wakeup and interrupt delivery time.
Testing on 80 HT 2 socket Xeon Skylake server, with 80 vCPUs VM 80GB RAM:
ebizzy -M
vanilla boosting improved
1VM 23000 21232 -9%
2VM 2800 8000 180%
3VM 1800 3100 72%
Testing on my Haswell desktop 8 HT, with 8 vCPUs VM 8GB RAM, two VMs,
one running ebizzy -M, the other running 'stress --cpu 2':
w/ boosting + w/o pv sched yield(vanilla)
vanilla boosting improved
1570 4000 55%
w/ boosting + w/ pv sched yield(vanilla)
vanilla boosting improved
1844 5157 79%
w/o boosting, perf top in VM:
72.33% [kernel] [k] smp_call_function_many
4.22% [kernel] [k] call_function_i
3.71% [kernel] [k] async_page_fault
w/ boosting, perf top in VM:
38.43% [kernel] [k] smp_call_function_many
6.31% [kernel] [k] async_page_fault
6.13% libc-2.23.so [.] __memcpy_avx_unaligned
4.88% [kernel] [k] call_function_interrupt
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Wanpeng Li <wanpengli@tencent.com>
---
virt/kvm/kvm_main.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index b4ab59d..2c46705 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -2404,8 +2404,10 @@ void kvm_vcpu_kick(struct kvm_vcpu *vcpu)
int me;
int cpu = vcpu->cpu;
- if (kvm_vcpu_wake_up(vcpu))
+ if (kvm_vcpu_wake_up(vcpu)) {
+ vcpu->preempted = true;
return;
+ }
me = get_cpu();
if (cpu != me && (unsigned)cpu < nr_cpu_ids && cpu_online(cpu))
--
2.7.4
next reply other threads:[~2019-07-12 7:10 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-07-12 7:10 Wanpeng Li [this message]
2019-07-15 10:53 ` [PATCH] KVM: Boosting vCPUs that are delivering interrupts Christian Borntraeger
2019-07-15 11:15 ` Wanpeng Li
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