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=-1.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS 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 4D513C433DF for ; Mon, 29 Jun 2020 19:17:13 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 24A49206E2 for ; Mon, 29 Jun 2020 19:17:13 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="A9TU9zrr" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731582AbgF2TRL (ORCPT ); Mon, 29 Jun 2020 15:17:11 -0400 Received: from us-smtp-2.mimecast.com ([205.139.110.61]:55572 "EHLO us-smtp-delivery-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1731963AbgF2TRJ (ORCPT ); Mon, 29 Jun 2020 15:17:09 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1593458228; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=oCU9JjYn8E5EJ3tgtkZ8fJQcI1jYdB8KZDv2+twV1/g=; b=A9TU9zrrWi35e6LxvVRWC3ssuzs97B2pnNvjC9jSNTDhQEBT9f1+XUZBVBY+pT4wv2TJz0 nDd9TUFapZWDpwXTSOtU3jc5nu8RU5GUfJq5dw6Q00NNVSePLwZPSXMTBuDc91BabDWL7y KuQJGaJiUKHGRXov1guNRhxcMQP4/2Y= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-230-UuU0pLxkNTqGodv5frl3IQ-1; Mon, 29 Jun 2020 15:17:04 -0400 X-MC-Unique: UuU0pLxkNTqGodv5frl3IQ-1 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id F09FE91362B; Mon, 29 Jun 2020 19:17:02 +0000 (UTC) Received: from krava (unknown [10.40.195.81]) by smtp.corp.redhat.com (Postfix) with SMTP id 261F71C4; Mon, 29 Jun 2020 19:17:00 +0000 (UTC) Date: Mon, 29 Jun 2020 21:17:00 +0200 From: Jiri Olsa To: Alexey Budankov Cc: Arnaldo Carvalho de Melo , Namhyung Kim , Alexander Shishkin , Peter Zijlstra , Ingo Molnar , Andi Kleen , linux-kernel Subject: Re: [PATCH v8 01/13] tools/libperf: avoid moving of fds at fdarray__filter() call Message-ID: <20200629191700.GC3031756@krava> References: <0781a077-aa82-5b4a-273e-c17372a72b93@linux.intel.com> <3d36dc7a-4249-096c-7554-80e6d290eac5@linux.intel.com> <20200625171405.GL2719003@krava> <688910f3-289e-d63e-79e3-0a17a6df0e9e@linux.intel.com> <20200626093745.GM2719003@krava> <6582201a-9570-709f-f6e9-5a644296f49d@linux.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Jun 29, 2020 at 06:11:52PM +0300, Alexey Budankov wrote: SNIP > >> > >> I'm confused, are you talking about file descriptors limit now? > >> this wont be affected by epoll change.. what do I miss? > > > > Currently there is already uname -n limit on the amount of open file descriptors > > and Perf tool process is affected by that limit. > > > > Moving to epoll() will impose one more max_user_watches limit and that can additionally > > confine Perf applicability even though default value on some machines currently > > is high enough. > > Prior making v9 I would prefer to agree on some design to be implemented in order to > avoid guessing and redundant reiterating. > > Options that I see as good balanced ones are 1) or 5), + non screwing of fds to fix > staleness of pos(=fdarray__add()). > > Are there any thoughts so far? let's try it and discuss over the code jirka