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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id DC159C001B0 for ; Sun, 23 Jul 2023 17:43:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229566AbjGWRny (ORCPT ); Sun, 23 Jul 2023 13:43:54 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33816 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229487AbjGWRnx (ORCPT ); Sun, 23 Jul 2023 13:43:53 -0400 Received: from s1.sapience.com (s1.sapience.com [72.84.236.66]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C5A11180; Sun, 23 Jul 2023 10:43:51 -0700 (PDT) Authentication-Results: dkim-srvy7; dkim=pass (Good ed25519-sha256 signature) header.d=sapience.com header.i=@sapience.com header.a=ed25519-sha256; dkim=pass (Good 2048 bit rsa-sha256 signature) header.d=sapience.com header.i=@sapience.com header.a=rsa-sha256 Received: from srv8.prv.sapience.com (srv8.prv.sapience.com [x.x.x.x]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (secp384r1) server-digest SHA384) (No client certificate requested) by s1.sapience.com (Postfix) with ESMTPS id CC9B2480A2C; Sun, 23 Jul 2023 13:43:50 -0400 (EDT) DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=sapience.com; i=@sapience.com; q=dns/txt; s=dk-ed25519-220413; t=1690134230; h=message-id : date : mime-version : subject : to : cc : references : from : in-reply-to : content-type : content-transfer-encoding : from; bh=qvqDvJ6z1X9pX7Hz0D/dTmd7iKskTuw2eAbBlB2IUA8=; b=GGLUkJ31b4aqlIQt6HoDwqanAilkCW4FtvSMmEaSUEWT8roDn1k8IDTXeU9/j4cjtxi4r qPOq30SiHCc03OjAg== ARC-Seal: i=1; a=rsa-sha256; d=sapience.com; s=arc6-rsa-220412; t=1690134230; cv=none; b=gFmye88JIl45MokehuUtQWprJPFmv7a9r6IGfDUrgigK3yUbjgfDDVr/MtDdxANlFUhzSGW0Lpuqs+zbA/ZmMT96X8y2BuUVbuBkkAaTXPPt7+PURlGtQSSw7zYyHf/lWuw1DNi8cEgKMCFUh4bCCsenwR0tZB+kWCh+qJ0lYB7tzeLrvBDItB8LgTMcG9VE2Bhl6VhIrQIo4cnt/6o1Prw04LXZ4bFEWeYYIhSbZF8BMV18lTHK7QX8K0mUnApjUhf+7XMpf4r4/O/hVZmglxiXtPj9HoYNy3MInkdw/U1I0k6BtgVBDSVQ3jGVEIW2dBENxp5YSxZMkkAz/dgqEA== ARC-Message-Signature: i=1; a=rsa-sha256; d=sapience.com; s=arc6-rsa-220412; t=1690134230; c=relaxed/simple; bh=kbvOZxDd3f2v9gt1kWG06Fh7pqlACOQ1tCnubhOp440=; h=DKIM-Signature:DKIM-Signature:Message-ID:Date:MIME-Version: User-Agent:Subject:Content-Language:To:Cc:References:From: In-Reply-To:Content-Type:Content-Transfer-Encoding; b=pEhJWsHNWS261GrUVRCnR0TcDCNy443AuPHsEGsKUDXhZLVoZXrn5z45HBlDz5Ukj6DV52+a2o0jKX35cOliJovQLfFvuLXAtMbw/RPpSNzJP9weWmlcjNoDY8CL4h/yZhr1hhM9Z/aR91CnCYdQw5dcp0cMF4h4cvGpt5uBu+IGdToW0tRrwm21nGgbNF6OszShZNBGDiwhCfgl5E2WebmUbJx/l3n1ZshcopPcydb8llK8temdPXeebJ79fPwNUhDP4R8HL1Ly64X542sYT8YyW+o93ta1CPUBmmGUzlnfy6d4ju9E9E0/JJEvue081JIhQoZaLo4fiOey1WjkpA== ARC-Authentication-Results: i=1; arc-srv8.sapience.com DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=sapience.com; i=@sapience.com; q=dns/txt; s=dk-rsa-220413; t=1690134230; h=message-id : date : mime-version : subject : to : cc : references : from : in-reply-to : content-type : content-transfer-encoding : from; bh=qvqDvJ6z1X9pX7Hz0D/dTmd7iKskTuw2eAbBlB2IUA8=; b=Rh9J5zY4+DAvkrIZm5dScnyFvaix14kjyjGMETV0BdlNQxJhVHoG1caSvcCsYEyBtS3XW 4MvTZPFlixQGJXinr15KtsH+ALm7uyuSgTQwjxypmywiCVhGYbp36QsAUd4h16OUr4GjUtL w8VTlSw59g8eKtu6LPLD4UdA56reXpysz6aHsR2fCP6C4wso2G8JCpjvcPlX57cqbJ8yPMa sK23RKNraPim0NXEPAO8HhRIT9pqVG+b1IphPzKUeJ76kJjYoyp9XRGqFgX520Ke9FwMTKV vEECVchxult78U8gjgCxcY/JxvHVHq6Mr8LAEzBO2K1cCp5e64iISbZPS+5w== Message-ID: <70e5349a-87af-a2ea-f871-95270f57c6e3@sapience.com> Date: Sun, 23 Jul 2023 13:43:50 -0400 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 6.4 800/800] io_uring: Use io_schedule* in cqring wait Content-Language: en-US To: Jens Axboe , Oleksandr Natalenko , stable@vger.kernel.org Cc: Greg Kroah-Hartman , Pavel Begunkov , io-uring@vger.kernel.org, linux-kernel@vger.kernel.org, Andres Freund References: <20230716194949.099592437@linuxfoundation.org> <20230716195007.731909670@linuxfoundation.org> <12251678.O9o76ZdvQC@natalenko.name> <538065ee-4130-6a00-dcc8-f69fbc7d7ba0@kernel.dk> From: Genes Lists In-Reply-To: <538065ee-4130-6a00-dcc8-f69fbc7d7ba0@kernel.dk> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: io-uring@vger.kernel.org On 7/23/23 11:31, Jens Axboe wrote: ... > Just read the first one, but this is very much expected. It's now just > correctly reflecting that one thread is waiting on IO. IO wait being > 100% doesn't mean that one core is running 100% of the time, it just > means it's WAITING on IO 100% of the time. > Seems reasonable thank you. Question - do you expect the iowait to stay high for a freshly created mariadb doing nothing (as far as I can tell anyway) until process exited? Or Would you think it would drop in this case prior to the process exiting. For example I tried the following - is the output what you expect? Create a fresh mariab with no databases - monitor the core showing the iowaits with: mpstat -P ALL 2 100 # rm -f /var/lib/mysql/* # mariadb-install-db --user=mysql --basedir=/usr --datadir=/var/lib/mysql # systemctl start mariadb (iowaits -> 100%) # iotop -bo |grep maria (shows no output, iowait stays 100%) (this persists until mariadb process exits) # systemctl stop mariadb (iowait drops to 0%)