From patchwork Sat Sep 25 00:55:18 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sean Christopherson X-Patchwork-Id: 12517117 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3F9EBC43219 for ; Sat, 25 Sep 2021 00:55:48 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 29CB0610EA for ; Sat, 25 Sep 2021 00:55:48 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1346401AbhIYA5Q (ORCPT ); Fri, 24 Sep 2021 20:57:16 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40308 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1346189AbhIYA5O (ORCPT ); Fri, 24 Sep 2021 20:57:14 -0400 Received: from mail-yb1-xb49.google.com (mail-yb1-xb49.google.com [IPv6:2607:f8b0:4864:20::b49]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3BF17C06161E for ; Fri, 24 Sep 2021 17:55:40 -0700 (PDT) Received: by mail-yb1-xb49.google.com with SMTP id q17-20020a25b591000000b005a07d27bbdaso5777465ybj.3 for ; Fri, 24 Sep 2021 17:55:40 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=reply-to:date:in-reply-to:message-id:mime-version:references :subject:from:to:cc; bh=FC6lH+ozNX1rSn/Zvey/qYq1p870FyZo4a/L9N/Tnnw=; b=H1jaweJg22GIvKz5wgIWDSWv9jBnold6xO8+Vir58J3vlW5yvGMJeY+RWUfUakOq0R orXdIRa207F1tk4zi8vuNL8CHfSf+xkMzWW/nJggJB4dETOCDuAFmo/uxwSrXfHa281o qUP6uOeam12R8fIodx3kiS3/hgxxDJx4AhPCjd3rZUC9XrvKS1+XNmDeTDwaJ19xQqhV cyard+R6ZMOtQO+e0PqanrPIokG2Of63+8xBF7DfYrbPWcKhcpKGH/k2SRB/D5Z/gfcU kBugNJHQN0/5+P2fD4RJGRBJy0JvWbzcwyoR231nRb6G1W76P8apmJbzeaDCVzireilR R6gQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:reply-to:date:in-reply-to:message-id :mime-version:references:subject:from:to:cc; bh=FC6lH+ozNX1rSn/Zvey/qYq1p870FyZo4a/L9N/Tnnw=; b=WJReFpmruO79SshBYhloBZMtp+gVQsgp9EZh7tlEp2pV1c+j0Gqx/E1LW4rjZ/eN+4 uoL5id3Z2qOPrVmcA5nNgjQw5oT5nHzFDNBVDxsngUOXd7TdpK1vLrBgdibH4zDBcrJT PntQ9WtyuFam0/ttN0bi//OpMqOMg2PtPMuHM9vzGqjoFWf2c/06/NdY+9TJBW8F32qV 0Q66sRwbPidKB7P2DX9DQ2yzXubydxM8NR3uBD6xwfqxaFxGGGFjPUXj6uJ1A1vc1yg4 rY+PPsbWojkI/VLrk74PjhAX+xTpnZQR789Qdu6DxZHkxkY7FLWxMui+8P5O6QtSFb4E CMGQ== X-Gm-Message-State: AOAM530eoNGvYv5/UNk6MFZmNrqQ8E/sYuiutuB4uD7SjxseopkmpJpv L4I0TXaZqj7oiM5RTeSCFUlLTaSea9w= X-Google-Smtp-Source: ABdhPJxLhkd4HzFL3dM1t/bnW3GVwOoYRsLTHfSU097HYEpOs+mMFMdF2Jxk4a9ePTkex/UXZCMknlTjhiQ= X-Received: from seanjc798194.pdx.corp.google.com ([2620:15c:90:200:4c72:89be:dba3:2bcb]) (user=seanjc job=sendgmr) by 2002:a25:d747:: with SMTP id o68mr16209002ybg.488.1632531339489; Fri, 24 Sep 2021 17:55:39 -0700 (PDT) Reply-To: Sean Christopherson Date: Fri, 24 Sep 2021 17:55:18 -0700 In-Reply-To: <20210925005528.1145584-1-seanjc@google.com> Message-Id: <20210925005528.1145584-5-seanjc@google.com> Mime-Version: 1.0 References: <20210925005528.1145584-1-seanjc@google.com> X-Mailer: git-send-email 2.33.0.685.g46640cef36-goog Subject: [PATCH 04/14] KVM: Reconcile discrepancies in halt-polling stats From: Sean Christopherson To: Marc Zyngier , Huacai Chen , Aleksandar Markovic , Paul Mackerras , Christian Borntraeger , Janosch Frank , Paolo Bonzini Cc: James Morse , Alexandru Elisei , Suzuki K Poulose , David Hildenbrand , Cornelia Huck , Claudio Imbrenda , Sean Christopherson , Vitaly Kuznetsov , Wanpeng Li , Jim Mattson , Joerg Roedel , linux-arm-kernel@lists.infradead.org, kvmarm@lists.cs.columbia.edu, linux-mips@vger.kernel.org, kvm@vger.kernel.org, kvm-ppc@vger.kernel.org, linux-kernel@vger.kernel.org, David Matlack , Jing Zhang Precedence: bulk List-ID: X-Mailing-List: linux-mips@vger.kernel.org Move the halt-polling "success" and histogram stats update into the dedicated helper to fix a discrepancy where the success/fail "time" stats consider polling successful so long as the wait is avoided, but the main "success" and histogram stats consider polling successful if and only if a wake event was detected by the halt-polling loop. Move halt_attempted_poll to the helper as well so that all the stats are updated in a single location. While it's a bit odd to update the stat well after the fact, practically speaking there's no meaningful advantage to updating before polling. Note, there is a functional change in addition to the success vs. fail change. The histogram updates previously called ktime_get() instead of using "cur". But that change is desirable as it means all the stats are now updated with the same polling time, and avoids the extra ktime_get(), which isn't expensive but isn't free either. Signed-off-by: Sean Christopherson Reviewed-by: David Matlack --- virt/kvm/kvm_main.c | 35 ++++++++++++++++------------------- 1 file changed, 16 insertions(+), 19 deletions(-) diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index 12fe91a0a4c8..2ba22b68af3b 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -3202,12 +3202,23 @@ static int kvm_vcpu_check_block(struct kvm_vcpu *vcpu) static inline void update_halt_poll_stats(struct kvm_vcpu *vcpu, ktime_t start, ktime_t end, bool success) { + struct kvm_vcpu_stat_generic *stats = &vcpu->stat.generic; u64 poll_ns = ktime_to_ns(ktime_sub(end, start)); - if (success) - vcpu->stat.generic.halt_poll_success_ns += poll_ns; - else - vcpu->stat.generic.halt_poll_fail_ns += poll_ns; + ++vcpu->stat.generic.halt_attempted_poll; + + if (success) { + ++vcpu->stat.generic.halt_successful_poll; + + if (!vcpu_valid_wakeup(vcpu)) + ++vcpu->stat.generic.halt_poll_invalid; + + stats->halt_poll_success_ns += poll_ns; + KVM_STATS_LOG_HIST_UPDATE(stats->halt_poll_success_hist, poll_ns); + } else { + stats->halt_poll_fail_ns += poll_ns; + KVM_STATS_LOG_HIST_UPDATE(stats->halt_poll_fail_hist, poll_ns); + } } /* @@ -3227,30 +3238,16 @@ void kvm_vcpu_block(struct kvm_vcpu *vcpu) if (do_halt_poll) { ktime_t stop = ktime_add_ns(ktime_get(), vcpu->halt_poll_ns); - ++vcpu->stat.generic.halt_attempted_poll; do { /* * This sets KVM_REQ_UNHALT if an interrupt * arrives. */ - if (kvm_vcpu_check_block(vcpu) < 0) { - ++vcpu->stat.generic.halt_successful_poll; - if (!vcpu_valid_wakeup(vcpu)) - ++vcpu->stat.generic.halt_poll_invalid; - - KVM_STATS_LOG_HIST_UPDATE( - vcpu->stat.generic.halt_poll_success_hist, - ktime_to_ns(ktime_get()) - - ktime_to_ns(start)); + if (kvm_vcpu_check_block(vcpu) < 0) goto out; - } cpu_relax(); poll_end = cur = ktime_get(); } while (kvm_vcpu_can_poll(cur, stop)); - - KVM_STATS_LOG_HIST_UPDATE( - vcpu->stat.generic.halt_poll_fail_hist, - ktime_to_ns(ktime_get()) - ktime_to_ns(start)); }