From: Waiman Long <longman@redhat.com>
To: Jeremy Fitzhardinge <jeremy@goop.org>,
Chris Wright <chrisw@sous-sol.org>,
Alok Kataria <akataria@vmware.com>,
Rusty Russell <rusty@rustcorp.com.au>,
Peter Zijlstra <peterz@infradead.org>,
Ingo Molnar <mingo@redhat.com>,
Thomas Gleixner <tglx@linutronix.de>,
"H. Peter Anvin" <hpa@zytor.com>
Cc: linux-arch@vger.kernel.org, x86@kernel.org,
linux-kernel@vger.kernel.org,
virtualization@lists.linux-foundation.org,
xen-devel@lists.xenproject.org, kvm@vger.kernel.org,
"Pan Xinhui" <xinhui.pan@linux.vnet.ibm.com>,
"Paolo Bonzini" <pbonzini@redhat.com>,
"Radim Krčmář" <rkrcmar@redhat.com>,
"Boris Ostrovsky" <boris.ostrovsky@oracle.com>,
"Juergen Gross" <jgross@suse.com>,
"Waiman Long" <longman@redhat.com>
Subject: [PATCH v4 0/2] x86/kvm: Reduce vcpu_is_preempted() overhead
Date: Wed, 15 Feb 2017 16:37:48 -0500 [thread overview]
Message-ID: <1487194670-6319-1-git-send-email-longman@redhat.com> (raw)
v3->v4:
- Fix x86-32 build error.
v2->v3:
- Provide an optimized __raw_callee_save___kvm_vcpu_is_preempted()
in assembly as suggested by PeterZ.
- Add a new patch to change vcpu_is_preempted() argument type to long
to ease the writing of the assembly code.
v1->v2:
- Rerun the fio test on a different system on both bare-metal and a
KVM guest. Both sockets were utilized in this test.
- The commit log was updated with new performance numbers, but the
patch wasn't changed.
- Drop patch 2.
As it was found that the overhead of callee-save vcpu_is_preempted()
can have some impact on system performance on a VM guest, especially
of x86-64 guest, this patch set intends to reduce this performance
overhead by replacing the C __kvm_vcpu_is_preempted() function by
an optimized version of __raw_callee_save___kvm_vcpu_is_preempted()
written in assembly.
Waiman Long (2):
x86/paravirt: Change vcp_is_preempted() arg type to long
x86/kvm: Provide optimized version of vcpu_is_preempted() for x86-64
arch/x86/include/asm/paravirt.h | 2 +-
arch/x86/include/asm/qspinlock.h | 2 +-
arch/x86/kernel/kvm.c | 32 +++++++++++++++++++++++++++++++-
arch/x86/kernel/paravirt-spinlocks.c | 2 +-
4 files changed, 34 insertions(+), 4 deletions(-)
--
1.8.3.1
next reply other threads:[~2017-02-15 21:38 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-02-15 21:37 Waiman Long [this message]
2017-02-15 21:37 ` [PATCH v4 1/2] x86/paravirt: Change vcp_is_preempted() arg type to long Waiman Long
2017-02-16 16:09 ` Peter Zijlstra
2017-02-16 21:02 ` Waiman Long
2017-02-17 9:42 ` Peter Zijlstra
2017-02-15 21:37 ` [PATCH v4 2/2] x86/kvm: Provide optimized version of vcpu_is_preempted() for x86-64 Waiman Long
2017-02-16 16:48 ` Peter Zijlstra
2017-02-16 21:00 ` Waiman Long
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