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=-5.5 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED,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 972D9C433E0 for ; Tue, 11 Aug 2020 08:12:44 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 7D8AC20678 for ; Tue, 11 Aug 2020 08:12:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728354AbgHKIMn (ORCPT ); Tue, 11 Aug 2020 04:12:43 -0400 Received: from mga11.intel.com ([192.55.52.93]:1493 "EHLO mga11.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728000AbgHKIMm (ORCPT ); Tue, 11 Aug 2020 04:12:42 -0400 IronPort-SDR: mYERgpeWGaI4Ce2imFbdxj1EXPQlvm7toEl1JkWtHcoCVG9wN6CL0K8HhQ1aSlE6RqYtlXboYs uD4kRfQdffbA== X-IronPort-AV: E=McAfee;i="6000,8403,9709"; a="151364737" X-IronPort-AV: E=Sophos;i="5.75,460,1589266800"; d="scan'208";a="151364737" X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga008.fm.intel.com ([10.253.24.58]) by fmsmga102.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 11 Aug 2020 01:12:42 -0700 IronPort-SDR: D4y46sC0Ef5ocWgaOIwdPWYAAuQXaDhiTLq/NhqmTn9hOqM2krynsy+9eCoCcMz7HHDsGpq3/D gQJLVyPROXog== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.75,460,1589266800"; d="scan'208";a="277511088" Received: from linux.intel.com ([10.54.29.200]) by fmsmga008.fm.intel.com with ESMTP; 11 Aug 2020 01:12:42 -0700 Received: from [10.249.225.27] (abudanko-mobl.ccr.corp.intel.com [10.249.225.27]) by linux.intel.com (Postfix) with ESMTP id 3D21F5807AA; Tue, 11 Aug 2020 01:12:40 -0700 (PDT) Subject: Re: [PATCH 1/2] perf: Add closing sibling events' file descriptors To: Peter Zijlstra , Andi Kleen , Alexander Shishkin Cc: Arnaldo Carvalho de Melo , Ingo Molnar , linux-kernel@vger.kernel.org, Jiri Olsa , adrian.hunter@intel.com References: <20200708151635.81239-1-alexander.shishkin@linux.intel.com> <20200708151635.81239-2-alexander.shishkin@linux.intel.com> <20200806083530.GV2674@hirez.programming.kicks-ass.net> <20200806153205.GA1448395@tassilo.jf.intel.com> <875z9q1u3g.fsf@ashishki-desk.ger.corp.intel.com> <20200810144518.GB1448395@tassilo.jf.intel.com> <20200810203632.GF3982@worktop.programming.kicks-ass.net> From: Alexey Budankov Organization: Intel Corp. Message-ID: Date: Tue, 11 Aug 2020 11:12:39 +0300 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:68.0) Gecko/20100101 Thunderbird/68.11.0 MIME-Version: 1.0 In-Reply-To: <20200810203632.GF3982@worktop.programming.kicks-ass.net> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 10.08.2020 23:36, Peter Zijlstra wrote: > On Mon, Aug 10, 2020 at 07:45:18AM -0700, Andi Kleen wrote: > >> Unfortunately we're kind of stuck with the old NFILE=1024 default >> even though it makes little sense on modern servers. > > Why can't that be changed? It seems to me all of userspace changes all > the time; heck that system-doofus thing flushed 20+ years of sysadmin > experience down the drain, just cause. Why can't we up a file limit? > If you asked me I would say that Intel VTune HW micro architecture analysis would also be unblocked by pushing RLIMIT_NOFILE limit beyond its current 1K default. Currently rule of thumb for VTune users is to set the limit to value == #cores X # events. The recommended value is 64K [1]. BR, Alexei [1] https://software.intel.com/content/www/us/en/develop/documentation/vtune-cookbook/top/configuration-recipes/profiling-hardware-without-sampling-drivers.html