From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.6 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 83F92C31E57 for ; Mon, 17 Jun 2019 11:25:28 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 56E5B2084A for ; Mon, 17 Jun 2019 11:25:28 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="erP9kbch" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727910AbfFQLYx (ORCPT ); Mon, 17 Jun 2019 07:24:53 -0400 Received: from mail-pg1-f194.google.com ([209.85.215.194]:38999 "EHLO mail-pg1-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726605AbfFQLYx (ORCPT ); Mon, 17 Jun 2019 07:24:53 -0400 Received: by mail-pg1-f194.google.com with SMTP id 196so5658735pgc.6; Mon, 17 Jun 2019 04:24:53 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=On7E7zmLSRgJj9Ttl1gLhH57uyxxO3PDcMqtYU/ZX3A=; b=erP9kbch+/6D93JrTKRtB/9WivFEV597MDMtDcNbuA81UdsF/WYopiQgFtZt/DdMeJ igUmflkUgVylTtJqDgqo86aOLhTQGCJ7asJo9ZxxpJNyOPfOm1OIL86ZhqEcpYGyxNwn RgmP/UFuTIo6+AqSDR71wxFk4anXVEitvA1Ggvre3ObKdVFfbNVXAWJAfXPczB0Zt0r+ sqI4k3bOulwes5gH7cGUU5Nuw91afJmAXO2mwkgA2bZjSvcYyNCUVEH0g2m1isp2tK5Z 9bSyYcqbidNKrqcpufW0wwImIVaWzme2sQo4yjWHetsWgyzB6SolI40aNKagtB6l27j/ ZocA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=On7E7zmLSRgJj9Ttl1gLhH57uyxxO3PDcMqtYU/ZX3A=; b=fBps6dQCbTfl0wNkHDUHCI5Mg8ivyLWpha5zbIhQSdBEX/0e6askYd2kMrhGheVbFY rqooEGEfgNhmsG344mpHeb6BtZy4O/RHhG3q/QCpjVlnyrB2Vma+ZRfWGlL89ebweJpE 170KFLDvjwX5qvT+E5QFL8odAbBh3ab3eIsnCPfRqheuEEzk7bjieS7rnUOYTOcgCLzl 2rmwWeXNbqxfpa8E38RKpyssehwRnZzHE9XlV+fyB7gCHYoYFfW/LbxeDdUwD2GbjVC2 X9AYAFJ0X77qhw7lBZHX+Mvp8v0sAar3Spbch3t4bzeoPLOSiAyqNcBjJYYPsJhMcknu 7abA== X-Gm-Message-State: APjAAAU2DegaufORrW1Z2N8ODfFKv4G6a+yVESCF0Xcvncjrp4Uguvne utO7OhrFi+4oCChndOaZx6lGM7yb X-Google-Smtp-Source: APXvYqysEiwTEoKS6WXujqPEY+h+jIj4Y7EPTe8opfIL0Wz6ucLZLbcZCZDZnoYc5R9JgXPTEzT5DA== X-Received: by 2002:a17:90a:ad93:: with SMTP id s19mr1033613pjq.36.1560770692765; Mon, 17 Jun 2019 04:24:52 -0700 (PDT) Received: from localhost.localdomain ([203.205.141.123]) by smtp.googlemail.com with ESMTPSA id d4sm12535751pfc.149.2019.06.17.04.24.50 (version=TLS1_2 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Mon, 17 Jun 2019 04:24:52 -0700 (PDT) From: Wanpeng Li X-Google-Original-From: Wanpeng Li To: linux-kernel@vger.kernel.org, kvm@vger.kernel.org Cc: Paolo Bonzini , =?UTF-8?q?Radim=20Kr=C4=8Dm=C3=A1=C5=99?= , Marcelo Tosatti Subject: [PATCH v4 0/5] KVM: LAPIC: Implement Exitless Timer Date: Mon, 17 Jun 2019 19:24:42 +0800 Message-Id: <1560770687-23227-1-git-send-email-wanpengli@tencent.com> X-Mailer: git-send-email 2.7.4 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org Dedicated instances are currently disturbed by unnecessary jitter due to the emulated lapic timers fire on the same pCPUs which vCPUs resident. There is no hardware virtual timer on Intel for guest like ARM. Both programming timer in guest and the emulated timer fires incur vmexits. This patchset tries to avoid vmexit which is incurred by the emulated timer fires in dedicated instance scenario. When nohz_full is enabled in dedicated instances scenario, the unpinned timer will be moved to the nearest busy housekeepers after commit 9642d18eee2cd (nohz: Affine unpinned timers to housekeepers) and commit 444969223c8 ("sched/nohz: Fix affine unpinned timers mess"). However, KVM always makes lapic timer pinned to the pCPU which vCPU residents, the reason is explained by commit 61abdbe0 (kvm: x86: make lapic hrtimer pinned). Actually, these emulated timers can be offload to the housekeeping cpus since APICv is really common in recent years. The guest timer interrupt is injected by posted-interrupt which is delivered by housekeeping cpu once the emulated timer fires. The host admin should fine tuned, e.g. dedicated instances scenario w/ nohz_full cover the pCPUs which vCPUs resident, several pCPUs surplus for busy housekeeping, disable mwait/hlt/pause vmexits to keep in non-root mode, ~3% redis performance benefit can be observed on Skylake server. w/o patchset: VM-EXIT Samples Samples% Time% Min Time Max Time Avg time EXTERNAL_INTERRUPT 42916 49.43% 39.30% 0.47us 106.09us 0.71us ( +- 1.09% ) w/ patchset: VM-EXIT Samples Samples% Time% Min Time Max Time Avg time EXTERNAL_INTERRUPT 6871 9.29% 2.96% 0.44us 57.88us 0.72us ( +- 4.02% ) Cc: Paolo Bonzini Cc: Radim Krčmář Cc: Marcelo Tosatti v3 -> v4: * drop the HRTIMER_MODE_ABS_PINNED, add kick after set pending timer * don't posted inject already-expired timer v2 -> v3: * disarming the vmx preemption timer when posted_interrupt_inject_timer_enabled() * check kvm_hlt_in_guest instead v1 -> v2: * check vcpu_halt_in_guest * move module parameter from kvm-intel to kvm * add housekeeping_enabled * rename apic_timer_expired_pi to kvm_apic_inject_pending_timer_irqs Wanpeng Li (5): KVM: LAPIC: Make lapic timer unpinned KVM: LAPIC: inject lapic timer interrupt by posted interrupt KVM: LAPIC: Ignore timer migration when lapic timer is injected by pi KVM: LAPIC: Don't posted inject already-expired timer KVM: LAPIC: add advance timer support to pi_inject_timer arch/x86/kvm/lapic.c | 62 ++++++++++++++++++++++++++++------------- arch/x86/kvm/lapic.h | 3 +- arch/x86/kvm/svm.c | 2 +- arch/x86/kvm/vmx/vmx.c | 5 ++-- arch/x86/kvm/x86.c | 11 ++++---- arch/x86/kvm/x86.h | 2 ++ include/linux/sched/isolation.h | 2 ++ kernel/sched/isolation.c | 6 ++++ 8 files changed, 64 insertions(+), 29 deletions(-) -- 2.7.4