From patchwork Tue Jul 23 07:38:23 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: maobibo X-Patchwork-Id: 13739666 Received: from mail.loongson.cn (mail.loongson.cn [114.242.206.163]) by smtp.subspace.kernel.org (Postfix) with ESMTP id A7E9114A4E9; Tue, 23 Jul 2024 07:38:28 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=114.242.206.163 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1721720311; cv=none; b=tCyQe2SsxD7Ognz4PIrP5J+eFe2kIKpwyz/rKXY6uEXg6WyOjyzLWO37cdcklP50gjGozAo/nlDFzn29eeIkTfi7e6mDt4o9LlB/O6q69Iq4YaHadDqZlaEitOTS7CwQemZn8HELvybnCkKU34Yz1U6NGaUt0YxHzUG3o6lWLMk= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1721720311; c=relaxed/simple; bh=ZTzMUqY8joLASIi7mv9v5tM2TSHOz+ePsO7TCtOMSVU=; h=From:To:Cc:Subject:Date:Message-Id:MIME-Version; b=nHEg1kyRVQ1zR07mDPTvBZqIzAMxsGr+YU9w9GyrNR93Bmc3N48cKc/q2tqFhzsLH9z4VRhpJ1fXxJCm5F03zDL1aHqc1aun+t7j5uGkO4jxS3CyKw2pQGuUKb6parKn8TZJ6uNs9MkiSjl5QN//ZWYLKQU0/ioxirR2gCfV9qs= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=loongson.cn; spf=pass smtp.mailfrom=loongson.cn; arc=none smtp.client-ip=114.242.206.163 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=loongson.cn Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=loongson.cn Received: from loongson.cn (unknown [10.2.5.213]) by gateway (Coremail) with SMTP id _____8CxvOryXZ9m6WAAAA--.1598S3; Tue, 23 Jul 2024 15:38:26 +0800 (CST) Received: from localhost.localdomain (unknown [10.2.5.213]) by localhost.localdomain (Coremail) with SMTP id AQAAf8DxusbxXZ9m+l9VAA--.59486S2; Tue, 23 Jul 2024 15:38:26 +0800 (CST) From: Bibo Mao To: Huacai Chen , Tianrui Zhao , Peter Zijlstra , Waiman Long Cc: WANG Xuerui , loongarch@lists.linux.dev, linux-kernel@vger.kernel.org, kvm@vger.kernel.org, virtualization@lists.linux.dev Subject: [PATCH 0/2] LoongArch: KVM: Add paravirt qspinlock support Date: Tue, 23 Jul 2024 15:38:23 +0800 Message-Id: <20240723073825.1811600-1-maobibo@loongson.cn> X-Mailer: git-send-email 2.39.3 Precedence: bulk X-Mailing-List: kvm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-CM-TRANSID: AQAAf8DxusbxXZ9m+l9VAA--.59486S2 X-CM-SenderInfo: xpdruxter6z05rqj20fqof0/ X-Coremail-Antispam: 1Uk129KBjDUn29KB7ZKAUJUUUUU529EdanIXcx71UUUUU7KY7 ZEXasCq-sGcSsGvfJ3UbIjqfuFe4nvWSU5nxnvy29KBjDU0xBIdaVrnUUvcSsGvfC2Kfnx nUUI43ZEXa7xR_UUUUUUUUU== Lock Holder Preemption (LHP) is classic problem especially on VM, if lock holder vCPU is preempted on host, other vCPUs will do busy looping and waste pCPU time. And there is no hw Pause Loop Exiting (PLE) supported on LoongArch system also. Here pavavirt qspinlock is introduced, by the kernel compiling test, it improves performance greatly if pVCPU is shared by multiple vCPUs. The testbed is on 3C5000 Dual-way machine with 32 cores and 2 numa nodes, test case is kcbench on kernel mainline 5.10, the detailed command is "kcbench --src /root/src/linux" Performance on host machine kernel compile time performance impact Original 150.29 seconds With patch 150.20 seconds almost no impact Performance on virtual machine: 1. 1 VM with 32 vCPUs and 2 numa node kernel compile time performance impact Original 173.07 seconds With patch 171.73 seconds +1% 2. 2 VMs with 32 vCPUs and 2 numa node kernel compile time performance impact Original 2362.04 seconds With patch 354.17 seconds +566% Bibo Mao (2): LoongArch: KVM: Add paravirt qspinlock in kvm side LoongArch: KVM: Add paravirt qspinlock in guest side arch/loongarch/Kconfig | 14 +++ arch/loongarch/include/asm/Kbuild | 1 - arch/loongarch/include/asm/kvm_host.h | 4 + arch/loongarch/include/asm/kvm_para.h | 1 + arch/loongarch/include/asm/loongarch.h | 1 + arch/loongarch/include/asm/paravirt.h | 47 ++++++++++ arch/loongarch/include/asm/qspinlock.h | 39 ++++++++ .../include/asm/qspinlock_paravirt.h | 6 ++ arch/loongarch/kernel/paravirt.c | 88 +++++++++++++++++++ arch/loongarch/kernel/smp.c | 4 +- arch/loongarch/kvm/exit.c | 24 ++++- arch/loongarch/kvm/vcpu.c | 13 ++- 12 files changed, 238 insertions(+), 4 deletions(-) create mode 100644 arch/loongarch/include/asm/qspinlock.h create mode 100644 arch/loongarch/include/asm/qspinlock_paravirt.h base-commit: 7846b618e0a4c3e08888099d1d4512722b39ca99