From mboxrd@z Thu Jan 1 00:00:00 1970 From: Subject: [PATCH 0/5] KVM: arm64: vcpu preempted check support Date: Tue, 17 Dec 2019 21:55:44 +0800 Message-ID: <20191217135549.3240-1-yezengruan__20361.4575600781$1576591023$gmane$org@huawei.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: virtualization-bounces@lists.linux-foundation.org Sender: "Virtualization" To: yezengruan@huawei.com, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, kvmarm@lists.cs.columbia.edu, kvm@vger.kernel.org, linux-doc@vger.kernel.org, virtualization@lists.linux-foundation.org Cc: mark.rutland@arm.com, suzuki.poulose@arm.com, catalin.marinas@arm.com, daniel.lezcano@linaro.org, linux@armlinux.org.uk, steven.price@arm.com, james.morse@arm.com, maz@kernel.org, will@kernel.org, julien.thierry.kdev@gmail.com List-Id: virtualization@lists.linuxfoundation.org From: Zengruan Ye This patch set aims to support the vcpu_is_preempted() functionality under KVM/arm64, which allowing the guest to obtain the vcpu is currently running or not. This will enhance lock performance on overcommitted hosts (more runnable vcpus than physical cpus in the system) as doing busy waits for preempted vcpus will hurt system performance far worse than early yielding. We have observed some performace improvements in uninx benchmark tests. unix benchmark result: host: kernel 5.5.0-rc1, HiSilicon Kunpeng920, 8 cpus guest: kernel 5.5.0-rc1, 16 vcpus test-case | after-patch | before-patch ----------------------------------------+-------------------+------------------ Dhrystone 2 using register variables | 334600751.0 lps | 335319028.3 lps Double-Precision Whetstone | 32856.1 MWIPS | 32849.6 MWIPS Execl Throughput | 3662.1 lps | 2718.0 lps File Copy 1024 bufsize 2000 maxblocks | 432906.4 KBps | 158011.8 KBps File Copy 256 bufsize 500 maxblocks | 116023.0 KBps | 37664.0 KBps File Copy 4096 bufsize 8000 maxblocks | 1432769.8 KBps | 441108.8 KBps Pipe Throughput | 6405029.6 lps | 6021457.6 lps Pipe-based Context Switching | 185872.7 lps | 184255.3 lps Process Creation | 4025.7 lps | 3706.6 lps Shell Scripts (1 concurrent) | 6745.6 lpm | 6436.1 lpm Shell Scripts (8 concurrent) | 998.7 lpm | 931.1 lpm System Call Overhead | 3913363.1 lps | 3883287.8 lps ----------------------------------------+-------------------+------------------ System Benchmarks Index Score | 1835.1 | 1327.6 Zengruan Ye (5): KVM: arm64: Document PV-lock interface KVM: arm64: Implement PV_LOCK_FEATURES call KVM: arm64: Support pvlock preempted via shared structure KVM: arm64: Add interface to support vcpu preempted check KVM: arm64: Support the vcpu preemption check Documentation/virt/kvm/arm/pvlock.rst | 31 +++++++++ arch/arm/include/asm/kvm_host.h | 13 ++++ arch/arm64/include/asm/kvm_host.h | 17 +++++ arch/arm64/include/asm/paravirt.h | 15 ++++ arch/arm64/include/asm/pvlock-abi.h | 16 +++++ arch/arm64/include/asm/spinlock.h | 7 ++ arch/arm64/kernel/Makefile | 2 +- arch/arm64/kernel/paravirt-spinlocks.c | 13 ++++ arch/arm64/kernel/paravirt.c | 95 +++++++++++++++++++++++++- arch/arm64/kernel/setup.c | 2 + arch/arm64/kvm/Makefile | 1 + include/linux/arm-smccc.h | 13 ++++ include/linux/cpuhotplug.h | 1 + virt/kvm/arm/arm.c | 8 +++ virt/kvm/arm/hypercalls.c | 7 ++ virt/kvm/arm/pvlock.c | 21 ++++++ 16 files changed, 260 insertions(+), 2 deletions(-) create mode 100644 Documentation/virt/kvm/arm/pvlock.rst create mode 100644 arch/arm64/include/asm/pvlock-abi.h create mode 100644 arch/arm64/kernel/paravirt-spinlocks.c create mode 100644 virt/kvm/arm/pvlock.c -- 2.19.1