From: Raghavendra K T <raghavendra.kt@linux.vnet.ibm.com>
To: "H. Peter Anvin" <hpa@zytor.com>,
Thomas Gleixner <tglx@linutronix.de>,
Marcelo Tosatti <mtosatti@redhat.com>,
Ingo Molnar <mingo@redhat.com>, Avi Kivity <avi@redhat.com>,
Rik van Riel <riel@redhat.com>
Cc: Srikar <srikar@linux.vnet.ibm.com>,
S390 <linux-s390@vger.kernel.org>,
Carsten Otte <cotte@de.ibm.com>,
Christian Borntraeger <borntraeger@de.ibm.com>,
KVM <kvm@vger.kernel.org>,
Raghavendra K T <raghavendra.kt@linux.vnet.ibm.com>,
chegu vinod <chegu_vinod@hp.com>,
"Andrew M. Theurer" <habanero@linux.vnet.ibm.com>,
LKML <linux-kernel@vger.kernel.org>, X86 <x86@kernel.org>,
Gleb Natapov <gleb@redhat.com>,
linux390@de.ibm.com,
Srivatsa Vaddagiri <srivatsa.vaddagiri@gmail.com>,
Joerg Roedel <joerg.roedel@amd.com>
Subject: [PATCH RFC V5 2/3] kvm: Note down when cpu relax intercepted or pause loop exited
Date: Wed, 18 Jul 2012 19:07:46 +0530 [thread overview]
Message-ID: <20120718133746.5321.74543.sendpatchset@codeblue.in.ibm.com> (raw)
In-Reply-To: <20120718133717.5321.71347.sendpatchset@codeblue.in.ibm.com>
From: Raghavendra K T <raghavendra.kt@linux.vnet.ibm.com>
Noting pause loop exited vcpu or cpu relax intercepted helps in
filtering right candidate to yield. Wrong selection of vcpu;
i.e., a vcpu that just did a pl-exit or cpu relax intercepted may
contribute to performance degradation.
Signed-off-by: Raghavendra K T <raghavendra.kt@linux.vnet.ibm.com>
---
V2 was:
Reviewed-by: Rik van Riel <riel@redhat.com>
include/linux/kvm_host.h | 34 ++++++++++++++++++++++++++++++++++
virt/kvm/kvm_main.c | 5 +++++
2 files changed, 39 insertions(+), 0 deletions(-)
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index c446435..34ce296 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -183,6 +183,18 @@ struct kvm_vcpu {
} async_pf;
#endif
+#ifdef CONFIG_HAVE_KVM_CPU_RELAX_INTERCEPT
+ /*
+ * Cpu relax intercept or pause loop exit optimization
+ * in_spin_loop: set when a vcpu does a pause loop exit
+ * or cpu relax intercepted.
+ * dy_eligible: indicates whether vcpu is eligible for directed yield.
+ */
+ struct {
+ bool in_spin_loop;
+ bool dy_eligible;
+ } spin_loop;
+#endif
struct kvm_vcpu_arch arch;
};
@@ -890,5 +902,27 @@ static inline bool kvm_check_request(int req, struct kvm_vcpu *vcpu)
}
}
+#ifdef CONFIG_HAVE_KVM_CPU_RELAX_INTERCEPT
+
+static inline void kvm_vcpu_set_in_spin_loop(struct kvm_vcpu *vcpu, bool val)
+{
+ vcpu->spin_loop.in_spin_loop = val;
+}
+static inline void kvm_vcpu_set_dy_eligible(struct kvm_vcpu *vcpu, bool val)
+{
+ vcpu->spin_loop.dy_eligible = val;
+}
+
+#else /* !CONFIG_HAVE_KVM_CPU_RELAX_INTERCEPT */
+
+static inline void kvm_vcpu_set_in_spin_loop(struct kvm_vcpu *vcpu, bool val)
+{
+}
+
+static inline void kvm_vcpu_set_dy_eligible(struct kvm_vcpu *vcpu, bool val)
+{
+}
+
+#endif /* CONFIG_HAVE_KVM_CPU_RELAX_INTERCEPT */
#endif
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 7e14068..3d6ffc8 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -236,6 +236,9 @@ int kvm_vcpu_init(struct kvm_vcpu *vcpu, struct kvm *kvm, unsigned id)
}
vcpu->run = page_address(page);
+ kvm_vcpu_set_in_spin_loop(vcpu, false);
+ kvm_vcpu_set_dy_eligible(vcpu, false);
+
r = kvm_arch_vcpu_init(vcpu);
if (r < 0)
goto fail_free_run;
@@ -1577,6 +1580,7 @@ void kvm_vcpu_on_spin(struct kvm_vcpu *me)
int pass;
int i;
+ kvm_vcpu_set_in_spin_loop(me, true);
/*
* We boost the priority of a VCPU that is runnable but not
* currently running, because it got preempted by something
@@ -1602,6 +1606,7 @@ void kvm_vcpu_on_spin(struct kvm_vcpu *me)
}
}
}
+ kvm_vcpu_set_in_spin_loop(me, false);
}
EXPORT_SYMBOL_GPL(kvm_vcpu_on_spin);
next prev parent reply other threads:[~2012-07-18 13:40 UTC|newest]
Thread overview: 41+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-07-18 13:37 [PATCH RFC V5 0/3] kvm: Improving directed yield in PLE handler Raghavendra K T
2012-07-18 13:37 ` [PATCH RFC V5 1/3] kvm/config: Add config to support ple or cpu relax optimzation Raghavendra K T
2012-07-18 13:37 ` Raghavendra K T [this message]
2012-07-18 13:38 ` [PATCH RFC V5 3/3] kvm: Choose better candidate for directed yield Raghavendra K T
2012-07-18 14:39 ` Raghavendra K T
2012-07-19 9:47 ` [RESEND PATCH " Raghavendra K T
2012-07-20 17:36 ` [PATCH RFC V5 0/3] kvm: Improving directed yield in PLE handler Marcelo Tosatti
2012-07-22 12:34 ` Raghavendra K T
2012-07-22 12:43 ` Avi Kivity
2012-07-23 7:35 ` Christian Borntraeger
2012-07-22 17:58 ` Rik van Riel
2012-07-23 10:03 ` Avi Kivity
2012-09-07 13:11 ` [RFC][PATCH] Improving directed yield scalability for " Andrew Theurer
2012-09-07 18:06 ` Raghavendra K T
2012-09-07 19:42 ` Andrew Theurer
2012-09-08 8:43 ` Srikar Dronamraju
2012-09-10 13:16 ` Andrew Theurer
2012-09-10 16:03 ` Peter Zijlstra
2012-09-10 16:56 ` Srikar Dronamraju
2012-09-10 17:12 ` Peter Zijlstra
2012-09-10 19:10 ` Raghavendra K T
2012-09-10 20:12 ` Andrew Theurer
2012-09-10 20:19 ` Peter Zijlstra
2012-09-10 20:31 ` Rik van Riel
2012-09-11 6:08 ` Raghavendra K T
2012-09-11 12:48 ` Andrew Theurer
2012-09-11 18:27 ` Andrew Theurer
2012-09-13 11:48 ` Raghavendra K T
2012-09-13 21:30 ` Andrew Theurer
2012-09-14 17:10 ` Andrew Jones
2012-09-15 16:08 ` Raghavendra K T
2012-09-17 13:48 ` Andrew Jones
2012-09-14 20:34 ` Konrad Rzeszutek Wilk
2012-09-17 8:02 ` Andrew Jones
2012-09-16 8:55 ` Avi Kivity
2012-09-17 8:10 ` Andrew Jones
2012-09-18 3:03 ` Andrew Theurer
2012-09-19 13:39 ` Avi Kivity
2012-09-13 12:13 ` Avi Kivity
2012-09-11 7:04 ` Srikar Dronamraju
2012-09-10 14:43 ` Raghavendra K T
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