Received: by 2002:a25:e74b:0:0:0:0:0 with SMTP id e72csp1362468ybh; Thu, 23 Jul 2020 07:07:03 -0700 (PDT) X-Google-Smtp-Source: ABdhPJw6M3xa4EB7+kjmt5sSVVJykN05Q3TEjoqXDJaUBdF5LI9HblWM5kdPCDBpssiV4exnLICA X-Received: by 2002:a17:906:60d0:: with SMTP id f16mr4430525ejk.17.1595513223336; Thu, 23 Jul 2020 07:07:03 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1595513223; cv=none; d=google.com; s=arc-20160816; b=ld4TSyfez8tsBExcTYiYRlqPRyuezOwVCotShi3OJNDBXFM3/SirzNVOGIwTMoRYSF +5rWZirhlqqqMNlPOva/4J/IAQ+rIbw8+SJRcKIQD1TmqtCoRMiyRPlZaCzs4oCRRBPj KBIYBvOUsMG/wYjfPl/WQWaAIfdcA3LubAf0raYRl23enjAgi7B0ZT8p47WcuHy+WTw2 8N/4pEXxGi2r0qkvMGYSMW6HZSrT+hi7n/C4u1I9lf8Vz01IgqmddmI+FT1rSPiECjYp zyVJDuU7nCl8FgripmJxrPX67AB7EoxNHp4gK72nVREdLx23OGTnNrVQGBVh1RKfBOwR 5YJg== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:sender:content-transfer-encoding :content-language:mime-version:user-agent:date:message-id:cc:to :subject:from; bh=mWlUJ91mkUaoGBInJarrvfom1FMpCyaYybPHxsZDrqA=; b=hLgLeb8lONaluXgRzXE7vYtPK0UtUSM4X7IQ7U1gQNPyBiTPfXxWGXbSsP0Nft93rV J4USRfCGDmsZjaA+gTl/RK+nfyQJx5qDZVPvtU5B8d+N46yJzWLp4DCmcegAwYJJ3X5K A0ABVN9cs2RaVjH+68QG4bTRf7+3VYk8TVU0fd8YI1iEj81U4BfLm3bVfJv5PirZIJji etxMPhoFXMTWiLe6qOh/+TqWVI4BPrvCvOPrRNB08+zUD4hOiyT+to+y3S9FaoBmkxPp duKKOmREc97ifouXT+mkfZYO79kN1abcId3F2oNQ2SJTp4EZQSHUP4eLn2my1JYmr4NO kVrg== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Return-Path: Received: from vger.kernel.org (vger.kernel.org. [23.128.96.18]) by mx.google.com with ESMTP id lc2si2029385ejb.424.2020.07.23.07.06.40; Thu, 23 Jul 2020 07:07:03 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18; Authentication-Results: mx.google.com; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727859AbgGWODU (ORCPT + 99 others); Thu, 23 Jul 2020 10:03:20 -0400 Received: from mx3.molgen.mpg.de ([141.14.17.11]:49867 "EHLO mx1.molgen.mpg.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726089AbgGWODU (ORCPT ); Thu, 23 Jul 2020 10:03:20 -0400 Received: from [141.14.220.45] (g45.guest.molgen.mpg.de [141.14.220.45]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) (Authenticated sender: pmenzel) by mx.molgen.mpg.de (Postfix) with ESMTPSA id 6395B2002EE3C; Thu, 23 Jul 2020 16:03:19 +0200 (CEST) From: Paul Menzel Subject: CPU pressure despite low load average To: Johannes Weiner Cc: LKML Message-ID: Date: Thu, 23 Jul 2020 16:03:19 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed 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 Dear Johannes, I am wondering, how PSI shows some CPU pressure (on average), while the load average, on a four thread system, shows a value well below four. > $ grep -R . /proc/pressure/ > /proc/pressure/io:some avg10=0.00 avg60=0.00 avg300=0.00 total=941766173 > /proc/pressure/io:full avg10=0.00 avg60=0.00 avg300=0.00 total=818872877 > /proc/pressure/cpu:some avg10=1.24 avg60=1.05 avg300=1.18 total=7522879562 > /proc/pressure/memory:some avg10=0.00 avg60=0.00 avg300=0.00 total=62730674 > /proc/pressure/memory:full avg10=0.00 avg60=0.00 avg300=0.00 total=37176371 > $ uptime > 15:50:39 up 8 days, 7:17, 1 user, load average: 0,90, 0,62, 0,60 Kind regards, Paul