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=-5.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE, SPF_PASS,USER_AGENT_SANE_1 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 D0ECEC43464 for ; Thu, 17 Sep 2020 22:03:07 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 98328208DB for ; Thu, 17 Sep 2020 22:03:07 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726222AbgIQWDG (ORCPT ); Thu, 17 Sep 2020 18:03:06 -0400 Received: from mga02.intel.com ([134.134.136.20]:53571 "EHLO mga02.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725900AbgIQWDD (ORCPT ); Thu, 17 Sep 2020 18:03:03 -0400 IronPort-SDR: uu/wxQODTaCjlLprElxj/rds3HL3MUJMVWKlfae8Ma0Nlg+x/O2Ne326NCM8TX2v2mbce9ihrL DFtLFwJfg6rw== X-IronPort-AV: E=McAfee;i="6000,8403,9747"; a="147490559" X-IronPort-AV: E=Sophos;i="5.77,272,1596524400"; d="scan'208";a="147490559" X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga006.jf.intel.com ([10.7.209.51]) by orsmga101.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 17 Sep 2020 15:02:59 -0700 IronPort-SDR: IRi5f7Ofh3H3yijZTfc5ZDEVl1Q5J/qcpNyYwT4SyKtW/PCTzBfA9Iyd/2Cte6kSnRcHUi2nci yJe8F6cWVQwg== X-IronPort-AV: E=Sophos;i="5.77,272,1596524400"; d="scan'208";a="307634816" Received: from kpgoodma-desk.amr.corp.intel.com (HELO [10.254.88.157]) ([10.254.88.157]) by orsmga006-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 17 Sep 2020 15:02:58 -0700 Subject: Re: [PATCH V7 1/4] perf/core: Add PERF_SAMPLE_DATA_PAGE_SIZE To: "Liang, Kan" , peterz@infradead.org, mingo@redhat.com, acme@kernel.org, linux-kernel@vger.kernel.org Cc: mark.rutland@arm.com, alexander.shishkin@linux.intel.com, jolsa@redhat.com, eranian@google.com, ak@linux.intel.com, kirill.shutemov@linux.intel.com, mpe@ellerman.id.au, benh@kernel.crashing.org, paulus@samba.org References: <20200917135237.2857-1-kan.liang@linux.intel.com> <20200917135237.2857-2-kan.liang@linux.intel.com> <13427458-3934-1490-68bb-071be2ae01da@intel.com> <40234c70-720e-9c0d-1fc2-ac23c0acf721@linux.intel.com> <04f59f3b-2e53-8774-8333-63dfc5b8e6a9@intel.com> <0e2cd6e4-8016-ccf6-eaff-2b304cf966ee@linux.intel.com> From: Dave Hansen Autocrypt: addr=dave.hansen@intel.com; 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Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: <0e2cd6e4-8016-ccf6-eaff-2b304cf966ee@linux.intel.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 9/17/20 2:58 PM, Liang, Kan wrote: > The user space perf tool looks like a better place for this kind of > warning. The perf tool knows the total number of the samples. It also > knows the number of the page size 0 samples. We can set a threshold, > e.g., 90%. If 90% of the samples have the page size 0, perf tool will > throw out a warning message. Sounds good to me. > The problem is that the warning from the perf tool usually includes some > hints regarding the cause of the warning or possible solution to > workaround/fix the warning. What message should we deliver to the users? > "Warning: Too many error page size. Address space isolation feature may > be enabled, please check"? That's not particularly actionable for an end user. Do any of the perf errors just tell them to submit a bug report? "Excessive number of page size lookup errors, please report to..."