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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id E46CAFA3743 for ; Thu, 27 Oct 2022 22:14:20 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235194AbiJ0WOT (ORCPT ); Thu, 27 Oct 2022 18:14:19 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48836 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235017AbiJ0WOR (ORCPT ); Thu, 27 Oct 2022 18:14:17 -0400 Received: from mail-pf1-x436.google.com (mail-pf1-x436.google.com [IPv6:2607:f8b0:4864:20::436]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8E7F2A5715 for ; Thu, 27 Oct 2022 15:14:16 -0700 (PDT) Received: by mail-pf1-x436.google.com with SMTP id k22so3132716pfd.3 for ; Thu, 27 Oct 2022 15:14:16 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:from:to:cc:subject:date:message-id:reply-to; bh=/Xa0F8qgJ/XT5i9ZprCu/QXLKvweAlKXJv8Fq2HmtIk=; b=n7xeD3rv2I1oxiz8y434ljm2W4kUXy1IZeL0QRTw7VgLVKRhCHoRYKW2Soxvd6TmkR uKqugoxuQVWFkHMzSCZnpxEtFKHIr3eTpBnKRUup9a9utVkYtSIfIraKEGPnWtkJgLRF 97hQSY5C5qRn7moAthqVyCKJVfminUx0z+rI/ucjMwTFaL1ZALWN5gAZ6f0k42yFZrK6 AjXyXq4FQOkyxnUAExBuWu+BgKlf7i/AOzCTAdWfcesNF0k5Bpklj6IiYzbQB1fUfvtT Q4dui1HnSnPAGm2n7ye8r/desdGEVZq8YP2D4rQWgZBEXAD0uff8iQHTK2OZIDrVV3+m rXAQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=/Xa0F8qgJ/XT5i9ZprCu/QXLKvweAlKXJv8Fq2HmtIk=; b=g/Zce6qz0A9vjv6xXMjYIWInYdoSgPH8rwPNgh9eYEktrO9qYFY4KUw6hISjne8vbZ CS50h8vAydSZyI+/JZSa/KXTQ+Zpcxf0Uajs77N7kQJmvkd2Hvx8s1OcJmr4xonDVVyW FbNlWUtEhaF1NaRBC0jee2WupggspAqeoFujQAPGvwDltIyos96WMz1k5qM4+vNWk446 kKCNAOg/GjoGaalL0dA+19DP+UVkizk3DbXR6RT4knKn7o0mVzz5YXIEon10OYeeZZYW Q27VqQxZsAYFI3SBNeov3t7bQJAhaI264p03OJSFvCBIG+cV4sBXJbcLeZKJJW4kGIcz B3Eg== X-Gm-Message-State: ACrzQf2aypA7sq+E2ulbky8K6QVU0fjs98EmvzaavlecIILcAYRYrE/i olPbaAnqZfmBlvVT2xmsVjhKxg== X-Google-Smtp-Source: AMsMyM5HcewplEwiZgZ1lxCb4X0WugaOkwaYG8PbaEvuFAAVxc08bBFDNJL9bmBaX/tD8Ncrcns9gg== X-Received: by 2002:a65:5583:0:b0:461:25fe:e982 with SMTP id j3-20020a655583000000b0046125fee982mr43490428pgs.4.1666908856011; Thu, 27 Oct 2022 15:14:16 -0700 (PDT) Received: from google.com (7.104.168.34.bc.googleusercontent.com. [34.168.104.7]) by smtp.gmail.com with ESMTPSA id 19-20020a170902c21300b0017f7628cbddsm1676863pll.30.2022.10.27.15.14.15 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 27 Oct 2022 15:14:15 -0700 (PDT) Date: Thu, 27 Oct 2022 22:14:12 +0000 From: Sean Christopherson To: Like Xu Cc: Jim Mattson , Paolo Bonzini , kvm@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2 1/3] KVM: x86/pmu: Make part of the Intel v2 PMU MSRs handling x86 generic Message-ID: References: <20220919093453.71737-1-likexu@tencent.com> <20220919093453.71737-2-likexu@tencent.com> <856e3332-9f6b-a5f7-c3ec-afe89003cb84@gmail.com> <6525670b-eb27-d0a5-2d03-cfa2006d0579@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <6525670b-eb27-d0a5-2d03-cfa2006d0579@gmail.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Sep 22, 2022, Like Xu wrote: > Subject: [PATCH] KVM: x86/pmu: Rewrite reprogram_counters() to improve > performance > > Before using pmu->reprogram_pmi, the test for a valid pmc is always > applied. This part of the redundancy could be removed by setting the > counters' bitmask directly, and furthermore triggering KVM_REQ_PMU > only once to save more cycles. Assuming you plan on posting this, please explicitly state what the patch does. "This part of the redundancy could" only says what _could_ be done, not what is actually done. Oftentimes, a changelog will say something "could" be done when talking about alternative solutions. So when I see "could", I think "this is what the patch _isn't_ doing".