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=1.5 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FSL_HELO_FAKE,MAILING_LIST_MULTI,SPF_PASS, URIBL_BLOCKED,USER_AGENT_MUTT autolearn=no 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 DD2CAC10F03 for ; Thu, 25 Apr 2019 06:39:16 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A80DE20651 for ; Thu, 25 Apr 2019 06:39:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1556174356; bh=gegyX4cOOMMxlxYmd37rT1ZX3/5qrHTkC7/BaOLUC3I=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=TQj7fdcILkO39+mjhcavO1RQMCIL6FKhxvuoWy4GFOxiqQDk7VrTzJk6Khf6uhUhe e4Q2z91ZFI49YsrEXOMSpf4My80XllA+7NzcwCnH7v81zgbnssfKagp8VpM8cYjUdb Kw7t8OJuB1t71tZB5dq0sjkim8x2Vzh4QjZTfrYs= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729861AbfDYGjP (ORCPT ); Thu, 25 Apr 2019 02:39:15 -0400 Received: from mail-wr1-f41.google.com ([209.85.221.41]:36203 "EHLO mail-wr1-f41.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727423AbfDYGjP (ORCPT ); Thu, 25 Apr 2019 02:39:15 -0400 Received: by mail-wr1-f41.google.com with SMTP id b1so17277667wru.3 for ; Wed, 24 Apr 2019 23:39:14 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=sender:date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=49jyvm4jbSuvTm0ekjcyI5ABuC9QUpA5l+m6y30ike4=; b=l/84KkULHRRSr+R2THoVAtpGeXhkH3D7cH7sImUc/rCUcr9gnXbYnipiZkdf6Hsx5n B1eOr4gpCWHQsyRRtsj8fm0+sICTWkkFgvlCGUVvPmwRn6+PcuxMgcvTkzoF6I4I4ysC VNOa/EozxLi2VNhdcDIBkEW+6yHQDd3O9UthJZ9e5P7oc8Lr8kgQKJnvEYXJXW6SWw1g g8KcG8HBmsKziTtfV0R/BQ732SJqtg7/PLihM2REN7FOLLTZvZ/D7tL/8+BL4JUm+WHN QpF1226QO7oBCBaaTdm+wTIkKKq+9ie5XKF7FOLazeNoJyIxby/QoPaTBq0zMdzXklJs LQEw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:sender:date:from:to:cc:subject:message-id :references:mime-version:content-disposition:in-reply-to:user-agent; bh=49jyvm4jbSuvTm0ekjcyI5ABuC9QUpA5l+m6y30ike4=; b=Vxwww7wJqSJ8hdffIbo/1V8m04kFXhaRX9+TPydiYx+hkTibObKxg+DexILC1Qcg6q ZTW3Ie34RFq8e9gS+oIu6pk4ivYPKn4N+7kalMamf4AFmITIXvhSQtPqmeHV2mmdSN/j E59XRTIWN7wSbmp3xTHYdJunBzuaDSCSeAgEFQ3lBe9q2nZcAJSMF664xhK4rGGMtjjO D13YuplHzGorQfy+5jrINzkTLWCZ5EXuChkfza7h1oIC8R99DtXxCQI0NRfvw9AZ4eh1 yQ6sU2YF0gIx6dnIqQA1zsUIZRMtiq+OJgjORLZ6vaCXL3tg50DweVnhPzOac4RJDaj9 szOA== X-Gm-Message-State: APjAAAUhYEEdzRawlkecfeO9m20YJNpKvueckG+ZAMvJGkg3X1xZOqRp 76jhzlgXZojIEpj12pSrt48iILSx X-Google-Smtp-Source: APXvYqxFlngF18ZfSHpY6NKkN7fS92liLwogZ6klzSj0ohH0wxvq7E3nrTeHK/GeCbYBr/24KT+onQ== X-Received: by 2002:adf:fa47:: with SMTP id y7mr25694364wrr.27.1556174353471; Wed, 24 Apr 2019 23:39:13 -0700 (PDT) Received: from gmail.com (2E8B0CD5.catv.pool.telekom.hu. [46.139.12.213]) by smtp.gmail.com with ESMTPSA id y197sm22396040wmd.34.2019.04.24.23.39.12 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Wed, 24 Apr 2019 23:39:12 -0700 (PDT) Date: Thu, 25 Apr 2019 08:39:10 +0200 From: Ingo Molnar To: kan.liang@linux.intel.com Cc: acme@redhat.com, mingo@redhat.com, linux-kernel@vger.kernel.org, jolsa@redhat.com, namhyung@gmail.com, lgoncalv@redhat.com, ak@linux.intel.com Subject: Re: [PATCH] perf stat: Add hint for SMI cost measurement Message-ID: <20190425063910.GA85646@gmail.com> References: <1556120792-35415-1-git-send-email-kan.liang@linux.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1556120792-35415-1-git-send-email-kan.liang@linux.intel.com> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org * kan.liang@linux.intel.com wrote: > +static void smi_env_check(void) > +{ > + char *name; > + size_t len; > + > + if (sysfs__read_str(CPUIDLE_CUR_DRV, &name, &len)) { > + pr_warning("Failed to check cstate status.\n"); What a meaningless message. What did we want to do, what happened, and why did it fail? > + return; > + } > + > + if (strncmp(name, "none", 4)) { > + pr_warning("Cstate may cause drift between aperf and cycles. " > + "Please completely disable cstate, " > + "E.g. set idle=poll in grub\n"); Please keep user-visible strings in the same form that the user sees them, i.e. in a single line. By doing that you'll also note a capitalization error. Also what does 'Cstate may cause drift' mean? What aspect of cstates causes the drift - entering/exiting deeper cstates that are not C0? If so then say so. Thanks, Ingo