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=-15.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,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 56879C433B4 for ; Fri, 9 Apr 2021 04:18:49 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 286D261168 for ; Fri, 9 Apr 2021 04:18:49 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229874AbhDIES7 (ORCPT ); Fri, 9 Apr 2021 00:18:59 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35548 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229526AbhDIES4 (ORCPT ); Fri, 9 Apr 2021 00:18:56 -0400 Received: from mail-pg1-x52e.google.com (mail-pg1-x52e.google.com [IPv6:2607:f8b0:4864:20::52e]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D6F40C061761; Thu, 8 Apr 2021 21:18:44 -0700 (PDT) Received: by mail-pg1-x52e.google.com with SMTP id y32so2908158pga.11; Thu, 08 Apr 2021 21:18:44 -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:in-reply-to:references; bh=xaENlWbODyEto5XlOvRuMJolo5sGz0JfL3nPFrLfnfo=; b=WFOqixJdGiNjr07rL6it5V1WYpE09f3ANsOibIqH+z3m2ysCf1BWg5cRIEFrt+d8Km HEOq1TOYqfid8x+kcU6mSW5JRzTqFxJ+Wt6pzYHM1N1bHL08rf2f8yzGDbu5PZxkvTMH Rpv8xZHGxL6kvCCsjBzHPfYLFwGY1WAmKesKAdxSuTK+2xJocwInYWGLVrGAsyhMBn/6 gFsZ21i9XG+d8o5OPxJAtyhmk5zj9HFcKmuVSZNnV6ge1EgN80BNP+p0+Cwq97J4aOl4 kTOU2X2Jznp/xTkpcoxXjw9HHjG3nwvLC/a6Lo6sioTQoYYDCobo3BL2VyorIMohoeJL iSpA== 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:in-reply-to :references; bh=xaENlWbODyEto5XlOvRuMJolo5sGz0JfL3nPFrLfnfo=; b=LavGPdQIlOtE/aDYODL4nsZIE9RO9lVVtKZH4df84PUjBdKHTNGH7eUAR/E4ieGR0y h9Dn6SJYr6/TEYqU8l3hh2zJXhMLzyblAoqd1bAEIBSqvXjTKd+B4DiA7C9MdZRh4a+y 4p9gDu+FgT4tavBIhiCSVZs4cM6GfXYOThbuMlTg2YRL+V93XTFr9Bq4MHECVtjkFn1I KbKQpox73oMcxnVwK7nhzaIs/TqbYGxkQL0xIH6c2tvDo/MoVRwaQKP0DZaSqblx7QqD Hh1pkzkCNFjBgrPI4Tre+4XndBf/2X8uWxmGVtKBSACFhNEdM8e1qaS5HveQBWSgPrRr vIjQ== X-Gm-Message-State: AOAM533aeW8pdra8sY6yvh2Cgn7qtWHuMk8PpLu537DvN31SqpueM9If nj4wIM6+8mkBKRwKrA8lesA8Jstlzn0= X-Google-Smtp-Source: ABdhPJyasOZHxTZMMtmdH6OMq5eDliacx+llgkwbI4zN3cBwXe8Axv8eKrCkRfauuIP4Wo6PBCdy4g== X-Received: by 2002:a63:d755:: with SMTP id w21mr11514874pgi.400.1617941924255; Thu, 08 Apr 2021 21:18:44 -0700 (PDT) Received: from localhost.localdomain ([103.7.29.6]) by smtp.googlemail.com with ESMTPSA id gw24sm765553pjb.42.2021.04.08.21.18.42 (version=TLS1_2 cipher=ECDHE-ECDSA-AES128-GCM-SHA256 bits=128/128); Thu, 08 Apr 2021 21:18:43 -0700 (PDT) From: Wanpeng Li X-Google-Original-From: Wanpeng Li To: linux-kernel@vger.kernel.org, kvm@vger.kernel.org Cc: Paolo Bonzini , Sean Christopherson , Vitaly Kuznetsov , Wanpeng Li , Jim Mattson , Joerg Roedel Subject: [PATCH v2 2/3] KVM: X86: Count attempted/successful directed yield Date: Fri, 9 Apr 2021 12:18:30 +0800 Message-Id: <1617941911-5338-2-git-send-email-wanpengli@tencent.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1617941911-5338-1-git-send-email-wanpengli@tencent.com> References: <1617941911-5338-1-git-send-email-wanpengli@tencent.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Wanpeng Li To analyze some performance issues with lock contention and scheduling, it is nice to know when directed yield are successful or failing. Signed-off-by: Wanpeng Li --- v1 -> v2: * rename new vcpu stat * account success instead of ignore arch/x86/include/asm/kvm_host.h | 2 ++ arch/x86/kvm/x86.c | 24 ++++++++++++++++++------ 2 files changed, 20 insertions(+), 6 deletions(-) diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index 44f8930..5af7411 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -1126,6 +1126,8 @@ struct kvm_vcpu_stat { u64 halt_poll_success_ns; u64 halt_poll_fail_ns; u64 nested_run; + u64 directed_yield_attempted; + u64 directed_yield_successful; }; struct x86_instruction_info; diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 16fb395..f08e9b4 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -246,6 +246,8 @@ struct kvm_stats_debugfs_item debugfs_entries[] = { VCPU_STAT("halt_poll_success_ns", halt_poll_success_ns), VCPU_STAT("halt_poll_fail_ns", halt_poll_fail_ns), VCPU_STAT("nested_run", nested_run), + VCPU_STAT("directed_yield_attempted", directed_yield_attempted), + VCPU_STAT("directed_yield_successful", directed_yield_successful), VM_STAT("mmu_shadow_zapped", mmu_shadow_zapped), VM_STAT("mmu_pte_write", mmu_pte_write), VM_STAT("mmu_pde_zapped", mmu_pde_zapped), @@ -8211,21 +8213,31 @@ void kvm_apicv_init(struct kvm *kvm, bool enable) } EXPORT_SYMBOL_GPL(kvm_apicv_init); -static void kvm_sched_yield(struct kvm *kvm, unsigned long dest_id) +static void kvm_sched_yield(struct kvm_vcpu *vcpu, unsigned long dest_id) { struct kvm_vcpu *target = NULL; struct kvm_apic_map *map; + vcpu->stat.directed_yield_attempted++; + rcu_read_lock(); - map = rcu_dereference(kvm->arch.apic_map); + map = rcu_dereference(vcpu->kvm->arch.apic_map); if (likely(map) && dest_id <= map->max_apic_id && map->phys_map[dest_id]) target = map->phys_map[dest_id]->vcpu; rcu_read_unlock(); - if (target && READ_ONCE(target->ready)) - kvm_vcpu_yield_to(target); + if (!target || !READ_ONCE(target->ready)) + goto no_yield; + + if (kvm_vcpu_yield_to(target) <= 0) + goto no_yield; + + vcpu->stat.directed_yield_successful++; + +no_yield: + return; } int kvm_emulate_hypercall(struct kvm_vcpu *vcpu) @@ -8272,7 +8284,7 @@ int kvm_emulate_hypercall(struct kvm_vcpu *vcpu) break; kvm_pv_kick_cpu_op(vcpu->kvm, a0, a1); - kvm_sched_yield(vcpu->kvm, a1); + kvm_sched_yield(vcpu, a1); ret = 0; break; #ifdef CONFIG_X86_64 @@ -8290,7 +8302,7 @@ int kvm_emulate_hypercall(struct kvm_vcpu *vcpu) if (!guest_pv_has(vcpu, KVM_FEATURE_PV_SCHED_YIELD)) break; - kvm_sched_yield(vcpu->kvm, a0); + kvm_sched_yield(vcpu, a0); ret = 0; break; default: -- 2.7.4