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 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id CBE12C433F5 for ; Tue, 9 Nov 2021 16:32:10 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 637C461208 for ; Tue, 9 Nov 2021 16:32:10 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 637C461208 Authentication-Results: mail.kernel.org; dmarc=fail (p=reject dis=none) header.from=google.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=kvack.org Received: by kanga.kvack.org (Postfix) id 7BDE36B009B; Tue, 9 Nov 2021 11:32:09 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 746E96B009C; Tue, 9 Nov 2021 11:32:09 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 5E8626B009D; Tue, 9 Nov 2021 11:32:09 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0020.hostedemail.com [216.40.44.20]) by kanga.kvack.org (Postfix) with ESMTP id 4E10F6B009B for ; Tue, 9 Nov 2021 11:32:09 -0500 (EST) Received: from smtpin18.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay02.hostedemail.com (Postfix) with ESMTP id E81C76F622 for ; Tue, 9 Nov 2021 16:32:08 +0000 (UTC) X-FDA: 78789933936.18.17325DC Received: from mail-lj1-f169.google.com (mail-lj1-f169.google.com [209.85.208.169]) by imf22.hostedemail.com (Postfix) with ESMTP id AB216191C for ; Tue, 9 Nov 2021 16:32:06 +0000 (UTC) Received: by mail-lj1-f169.google.com with SMTP id e11so18179600ljo.13 for ; Tue, 09 Nov 2021 08:32:06 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=M/8dhRfwJVa4DbGul2wXDZMaW1G+0u9Zho02c+0fbvg=; b=i1zsHWvak0Z48bvXbSLAUT9qTUMXTZ/9dt4BWp0/Q5HLRsomYkzEeQm2ZeJhdLWGCv Gs9JaLDadSe+Zj5Jy3m5Y12u+A80/Qko0FnXeWbpwqvcxei2dfio3K6a0wLJi9PLR+MD tPFd57zm+C6gXyXBKIxRFhG6NL7YkBV+JXggQGswjgXIuhL0iMK82zv6Fa+lvA5iDu3d bJrm67+kGoOb7M0RqYvkhRgXePsjif9FZhUzQ0Tc34ssVGmWyMDFg+vPoG1ZWZETxPjj rX5ke2p7xfpXQDLbQyYyNXn7fR5Wwn6Gs8A9vp2kO1C/C0caI4YqRTvYHSQ7Qwt6ZoFL eH/w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=M/8dhRfwJVa4DbGul2wXDZMaW1G+0u9Zho02c+0fbvg=; b=f5ubLa7Qo1IDQ0tXG2gtJuJ0ekFlbjLJlRhdcCiGVnf7Egqpmz1s+Z83yRnuhTlGi7 vGmelKfocMlqGXuWqVvZV2IUH4mf6qOBzdcXt1X5/no6br2vjn0BZGqSC3bYPkN6FSqx hAP9T5C+pLE1ebIEPv7EEmzQrLFnWwuFQc+RL4FQlY4JqdUQ8kCu8Sc4TRsvYgRFMEzD eAXXKGBbhqj9d+5wBuyKOD2Vfq16TmPwDhjsV2X79dUQziDesIOakZOVYYck0Ugr5x0P CX+ahCUNzbxzv+4/hJbpDKsykBnmNka1eCM/WwZB3z9UxajnBruyTjEvIOXbVcDm8nlI SjwA== X-Gm-Message-State: AOAM533wgUl59oDqZP3xCqkcO+vIK5IEFQ6xqqQm1WZL2rDF9eEhV1VE F702xJmfN6GBJ6bNpNFIygPzSp5M/s3xtkpTdKyDlw== X-Google-Smtp-Source: ABdhPJzlzPHziQ7RTqVxchkRg4XOW7Q7HSp1BAF/VSiFuVRmTDjCPXv+cBjfftIRsY+yBCXKUVkRTXptkfRPlKkrijM= X-Received: by 2002:a05:651c:1101:: with SMTP id d1mr9135458ljo.373.1636475524928; Tue, 09 Nov 2021 08:32:04 -0800 (PST) MIME-Version: 1.0 References: <20211104195804.83240-1-posk@google.com> In-Reply-To: From: Peter Oskolkov Date: Tue, 9 Nov 2021 08:31:53 -0800 Message-ID: Subject: Re: [PATCH v0.8 0/6] sched,mm,x86/uaccess: implement User Managed Concurrency Groups To: Barry Song <21cnbao@gmail.com> Cc: posk@posk.io, Peter Zijlstra , Ingo Molnar , Thomas Gleixner , Andrew Morton , Dave Hansen , Andy Lutomirski , Linux-MM , LKML , linux-api@vger.kernel.org, Paul Turner , Ben Segall , Andrei Vagin , Jann Horn , Thierry Delisle Content-Type: text/plain; charset="UTF-8" X-Rspamd-Server: rspam05 X-Rspamd-Queue-Id: AB216191C X-Stat-Signature: esorawukdyr1c8xobqh64udqhwp4n4q3 Authentication-Results: imf22.hostedemail.com; dkim=pass header.d=google.com header.s=20210112 header.b=i1zsHWva; dmarc=pass (policy=reject) header.from=google.com; spf=pass (imf22.hostedemail.com: domain of posk@google.com designates 209.85.208.169 as permitted sender) smtp.mailfrom=posk@google.com X-HE-Tag: 1636475526-736930 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: Hi Barry, [...] > > Do you have a real workload or an example application using UMCG? > [...] A google-internal variant of UMCG kernel patches is used extensively to enable user-space scheduling of heterogeneous work items. The main use case is services that need to ensure user isolation; in addition, latency vs throughput workloads served by the same service are also well addressed by user-space schedulers. For example, a DBMS needs to ensure that one "hungry" user does not adversely affect other well-behaved users; but at the same time if the overall load is relatively low, users are allowed to go ahead and consume as much CPU as possible, as long as this does not affect other users negatively. Services that treat their work uniformly, and care only about raw throughput, usually do not benefit from custom user-space scheduling that UMCG, or similar, enables. Thanks, Peter