From: Zengruan Ye <yezengruan@huawei.com> To: <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: peterz@infradead.org, maz@kernel.org, daniel.lezcano@linaro.org, linux@armlinux.org.uk, steven.price@arm.com, longman@redhat.com, catalin.marinas@arm.com, will@kernel.org Subject: [PATCH v3 0/8] KVM: arm64: vCPU preempted check support Date: Thu, 16 Jan 2020 20:46:18 +0800 Message-ID: <20200116124626.1155-1-yezengruan@huawei.com> (raw) 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-rc5, HiSilicon Kunpeng920, 8 CPUs guest: kernel 5.5.0-rc5, 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 Changes from v2: https://lore.kernel.org/lkml/20191226135833.1052-1-yezengruan@huawei.com/ * Post Will's patches as part of this series [1][2], and add the probing logic for checking whether the hypervisor is KVM or not * Clear PV-lock interface documentation * Remove preempted state field * Fix build error when CONFIG_PARAVIRT is not set * Bunch of typo fixes. Changes from v1: https://lore.kernel.org/lkml/20191217135549.3240-1-yezengruan@huawei.com/ * Guest kernel no longer allocates the PV lock structure, instead it is allocated by user space to avoid lifetime issues about kexec. * Provide vCPU attributes for PV lock. * Update SMC number of PV lock features. * Report some basic validation when PV lock init. * Document preempted field. * Bunch of typo fixes. [1] https://git.kernel.org/pub/scm/linux/kernel/git/will/linux.git/commit/?h=kvm/hvc&id=464f5a1741e5959c3e4d2be1966ae0093b4dce06 [2] https://git.kernel.org/pub/scm/linux/kernel/git/will/linux.git/commit/?h=kvm/hvc&id=6597490e005d0eeca8ed8c1c1d7b4318ee014681 Will Deacon (2): arm64: Probe for the presence of KVM hypervisor services during boot arm/arm64: KVM: Advertise KVM UID to guests via SMCCC Zengruan Ye (6): KVM: arm64: Document PV-lock interface KVM: arm64: Add SMCCC paravirtualised lock calls KVM: arm64: Support pvlock preempted via shared structure KVM: arm64: Provide vCPU attributes for PV lock KVM: arm64: Add interface to support vCPU preempted check KVM: arm64: Support the vCPU preemption check Documentation/virt/kvm/arm/pvlock.rst | 68 +++++++++++++ Documentation/virt/kvm/devices/vcpu.txt | 14 +++ arch/arm/include/asm/kvm_host.h | 18 ++++ arch/arm64/include/asm/hypervisor.h | 11 ++ arch/arm64/include/asm/kvm_host.h | 27 +++++ arch/arm64/include/asm/paravirt.h | 15 +++ arch/arm64/include/asm/pvlock-abi.h | 16 +++ arch/arm64/include/asm/spinlock.h | 9 ++ arch/arm64/include/uapi/asm/kvm.h | 2 + arch/arm64/kernel/Makefile | 2 +- arch/arm64/kernel/paravirt-spinlocks.c | 13 +++ arch/arm64/kernel/paravirt.c | 129 +++++++++++++++++++++++- arch/arm64/kernel/setup.c | 37 +++++++ arch/arm64/kvm/Makefile | 1 + arch/arm64/kvm/guest.c | 9 ++ include/linux/arm-smccc.h | 36 +++++++ include/linux/cpuhotplug.h | 1 + include/uapi/linux/kvm.h | 2 + virt/kvm/arm/arm.c | 8 ++ virt/kvm/arm/hypercalls.c | 54 +++++++--- virt/kvm/arm/pvlock.c | 102 +++++++++++++++++++ 21 files changed, 559 insertions(+), 15 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 _______________________________________________ kvmarm mailing list kvmarm@lists.cs.columbia.edu https://lists.cs.columbia.edu/mailman/listinfo/kvmarm
next reply index Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top 2020-01-16 12:46 Zengruan Ye [this message] 2020-01-16 12:46 ` [PATCH v3 1/8] KVM: arm64: Document PV-lock interface Zengruan Ye 2020-01-20 16:20 ` Steven Price 2020-01-16 12:46 ` [PATCH v3 2/8] arm64: Probe for the presence of KVM hypervisor services during boot Zengruan Ye 2020-01-16 12:46 ` [PATCH v3 3/8] arm/arm64: KVM: Advertise KVM UID to guests via SMCCC Zengruan Ye 2020-01-16 12:46 ` [PATCH v3 4/8] KVM: arm64: Add SMCCC paravirtualised lock calls Zengruan Ye 2020-01-16 12:46 ` [PATCH v3 5/8] KVM: arm64: Support pvlock preempted via shared structure Zengruan Ye 2020-01-16 12:46 ` [PATCH v3 6/8] KVM: arm64: Provide vCPU attributes for PV lock Zengruan Ye 2020-01-16 12:46 ` [PATCH v3 7/8] KVM: arm64: Add interface to support vCPU preempted check Zengruan Ye 2020-01-16 12:46 ` [PATCH v3 8/8] KVM: arm64: Support the vCPU preemption check Zengruan Ye
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