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=-5.6 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_2 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 4A85EC433E1 for ; Thu, 13 Aug 2020 15:01:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 27D842087C for ; Thu, 13 Aug 2020 15:01:30 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="dqTYbUrY" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726648AbgHMPBT (ORCPT ); Thu, 13 Aug 2020 11:01:19 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47308 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726131AbgHMPBN (ORCPT ); Thu, 13 Aug 2020 11:01:13 -0400 Received: from mail-pf1-x441.google.com (mail-pf1-x441.google.com [IPv6:2607:f8b0:4864:20::441]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 30952C061757; Thu, 13 Aug 2020 08:01:10 -0700 (PDT) Received: by mail-pf1-x441.google.com with SMTP id d188so2953367pfd.2; Thu, 13 Aug 2020 08:01:10 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=date:from:to:cc:subject:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=g7E03oNbQL5OmaCxbJGHTzh+uQv70s9+Kim5awpFIOQ=; b=dqTYbUrYs0mBd8e3EbKh+zqOEvsS/8R4soFxtxGns5xFEKS2qbbYYRqAvq5km43kE+ hF6fNHIq2pMYlnPkoPrXaVMbJn/fLpcI8e2eoublbPhy6XrUp4xTK/A+2EOd+b4HfF1E FRl5AR08bNBYsPyUGaKAzu2vnDHz8qTOT0HG3qutkadMxyFZ3UtMrVasxMXiW+iMHKAj 1ab3xKURjjrzUMt3E4otiI3sKdi5/rWteLVhR9b/08zKSGGYybGekkF0nCtBVjlHig2D 54rku8msIu9QGfO4TT1Chy2tMuJzHErngz+NLOCctQqKSylPofQ9qPoGNz8t8buZrPws ELqA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=g7E03oNbQL5OmaCxbJGHTzh+uQv70s9+Kim5awpFIOQ=; b=Tkg2mXS2zk4F4zG5xQJtJcw+2Te9QqeZ7AkvuhBau641ltRFGyrdIj3vYE+8i33W04 U0urJTZrxDcsDkiaA4k+/Ae2dStKIh9UKzCTAIPTTF2CrvPWeVLXuPyloizjGl5+mdH5 D+UwGSGvSUlYEA53XWZU0C+sBCRV7OQeDXqUfVt6Q3ASfWxbwLoSyd10QrXziPtFuOa/ zaDRHubV4faQ5MOGNWphLxLvzEr/6I/XlLGoV7PeLMql+88BIZpV1Jx64lvUpATvtAmQ B91lLewLaq/9t9D2Cul0vybXpW8KPtD3YY8goti2oW4/wDKRMZlGvQv9S9gN3P5tZAwS 6tOg== X-Gm-Message-State: AOAM532DMuTzUfPKf1M/11lAUhMRfqjkwUGv+R7nKPQy8DuFJWvoF4gg ol+6hUYQv/khsKeYond0H1k= X-Google-Smtp-Source: ABdhPJzkmNJegWshCR53AYdFRG7i7LcGbOjQXWctMKCqdTAZwQjsckpLduH02hCIf4HYxkwpyAo0pQ== X-Received: by 2002:a63:2546:: with SMTP id l67mr4104702pgl.281.1597330868752; Thu, 13 Aug 2020 08:01:08 -0700 (PDT) Received: from eug-lubuntu ([203.63.226.116]) by smtp.gmail.com with ESMTPSA id h15sm5840666pjf.54.2020.08.13.08.01.06 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 13 Aug 2020 08:01:08 -0700 (PDT) Date: Fri, 14 Aug 2020 01:01:00 +1000 From: Eugene Lubarsky To: Andrei Vagin Cc: linux-api@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, adobriyan@gmail.com, dsahern@gmail.com Subject: Re: [RFC PATCH 0/5] Introduce /proc/all/ to gather stats from all processes Message-ID: <20200814010100.3e9b6423@eug-lubuntu> In-Reply-To: <20200812075135.GA191218@gmail.com> References: <20200810145852.9330-1-elubarsky.linux@gmail.com> <20200812075135.GA191218@gmail.com> X-Mailer: Claws Mail 3.17.5 (GTK+ 2.24.32; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org On Wed, 12 Aug 2020 00:51:35 -0700 Andrei Vagin wrote: > Maybe we need resurrect the task_diag series instead of inventing > another less-effective interface... I would certainly welcome the resurrection of task_diag - it is clearly more efficient than this /proc/all/ idea. It would be good to find out if there's anything in particular that's currently blocking it. This RFC is mainly meant to check whether such an addition would be acceptable from an API point of view. It currently has an obvious performance issue in that seq_file seems to only return one page at a time so lots of read syscalls are still required. However I may not have the time to figure out a proposed fix for this by myself. Regardless, text-based formats can't match the efficiency of task_diag, but binary ones are also possible. Best Wishes, Eugene