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=-2.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,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 D17DEC3B187 for ; Tue, 11 Feb 2020 15:07:36 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id ACC332086A for ; Tue, 11 Feb 2020 15:07:36 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730059AbgBKPHg (ORCPT ); Tue, 11 Feb 2020 10:07:36 -0500 Received: from lhrrgout.huawei.com ([185.176.76.210]:2408 "EHLO huawei.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1728574AbgBKPHf (ORCPT ); Tue, 11 Feb 2020 10:07:35 -0500 Received: from LHREML713-CAH.china.huawei.com (unknown [172.18.7.106]) by Forcepoint Email with ESMTP id 8D03C9F91ED670DD7329; Tue, 11 Feb 2020 15:07:33 +0000 (GMT) Received: from lhreml724-chm.china.huawei.com (10.201.108.75) by LHREML713-CAH.china.huawei.com (10.201.108.36) with Microsoft SMTP Server (TLS) id 14.3.408.0; Tue, 11 Feb 2020 15:07:33 +0000 Received: from [127.0.0.1] (10.202.226.45) by lhreml724-chm.china.huawei.com (10.201.108.75) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.1713.5; Tue, 11 Feb 2020 15:07:33 +0000 Subject: Re: [PATCH RFC 5/7] perf pmu: Support matching by sysid To: Jiri Olsa CC: , , , , , , , , , , , , , , References: <1579876505-113251-1-git-send-email-john.garry@huawei.com> <1579876505-113251-6-git-send-email-john.garry@huawei.com> <20200210120759.GG1907700@krava> <63799909-067b-e5f4-dcf1-9ba1ec145348@huawei.com> <20200211134704.GB93194@krava> From: John Garry Message-ID: <2a51ce93-fa68-8088-f31f-2fd692253335@huawei.com> Date: Tue, 11 Feb 2020 15:07:31 +0000 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:68.0) Gecko/20100101 Thunderbird/68.1.2 MIME-Version: 1.0 In-Reply-To: <20200211134704.GB93194@krava> Content-Type: text/plain; charset="utf-8"; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit X-Originating-IP: [10.202.226.45] X-ClientProxiedBy: lhreml720-chm.china.huawei.com (10.201.108.71) To lhreml724-chm.china.huawei.com (10.201.108.75) X-CFilter-Loop: Reflected Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 11/02/2020 13:47, Jiri Olsa wrote: Hi Jirka, >>>> + >>>> + return buf; >>>> +} >>>> + >> >> I have another series to add kernel support for a system identifier sysfs >> entry, which I sent after this series: >> >> https://lore.kernel.org/linux-acpi/1580210059-199540-1-git-send-email-john.garry@huawei.com/ >> >> It is different to what I am relying on here - it uses a kernel soc driver >> for firmware ACPI PPTT identifier. Progress is somewhat blocked at the >> moment however and I may have to use a different method: >> >> https://lore.kernel.org/linux-acpi/20200128123415.GB36168@bogus/ > > I'll try to check ;-) Summary is that there exists an ACPI firmware field which we could expose to userspace via sysfs - this would provide the system id. However there is a proposal to deprecate it in the ACPI standard and, as such, would prefer that we don't add kernel support for it at this stage. So I am evaluating the alternative in the meantime, which again is some firmware method which should allow us to expose a system id to userspace via sysfs. Unfortunately this is arm specific. However, other archs can still provide their own method, maybe a soc driver: Documentation/ABI/testing/sysfs-devices-soc#n15 > >> >>>> +static char *perf_pmu__getsysid(void) >>>> +{ >>>> + char *sysid; >>>> + static bool printed; >>>> + >>>> + sysid = getenv("PERF_SYSID"); >>>> + if (sysid) >>>> + sysid = strdup(sysid); >>>> + >>>> + if (!sysid) >>>> + sysid = get_sysid_str(); >>>> + if (!sysid) >>>> + return NULL; >>>> + >>>> + if (!printed) { >>>> + pr_debug("Using SYSID %s\n", sysid); >>>> + printed = true; >>>> + } >>>> + return sysid; >>>> +} >>> >>> this part is getting complicated and AFAIK we have no tests for it >>> >>> if you could think of any tests that'd be great.. Perhaps we could >>> load 'our' json test files and check appropriate events/aliasses >>> via in pmu object.. or via parse_events interface.. those test aliases >>> would have to be part of perf, but we have tests compiled in anyway >> >> Sorry, I don't fully follow. >> >> Are you suggesting that we could load the specific JSONs tables for a system >> from the host filesystem? > > I wish to see some test for all this.. I can only think about having > 'test' json files compiled with perf and 'perf test' that looks them > up and checks that all is in the proper place OK, let me consider this part for perf test support. Thanks, John