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 06801CE7B0C for ; Thu, 28 Sep 2023 08:38:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231200AbjI1IiE (ORCPT ); Thu, 28 Sep 2023 04:38:04 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44380 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229639AbjI1IiD (ORCPT ); Thu, 28 Sep 2023 04:38:03 -0400 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 34EA4AC; Thu, 28 Sep 2023 01:38:01 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=z8GzI+kpy3OQpRgGXC2447CS8SW2V4ydnhao9KzknII=; b=dv67282FkROq+rxj7+zjDGZRAe c22MFYLUqQdFaCICkn9c/JwsLXsziF0Aa20hcfdtVvZS5oBuvH3QP3jMmHtxf2fjgEJV73X36DTdQ 6IzQ4OCBy66CT3a7cysZmfV+HA2C4in6oIQdQR3rCpNoSzy8YxY0zibLNv44OyQxHHDSIs+SyEErx TGvjE3zNZeg/3STOiQjol+U9rc9rJICOb7O+Q1RXUJMC+/aWSVPrH5LgRbMGDp50KuY7L3uG4S79Q 2+Mlf7Y6gZPWtolavgWqnvLATMQN603fWGfdIjB624EavJCtWYuIKsCIGdF9F3N2W5SrBBELiW6Cj G8vY/z9A==; Received: from willy by casper.infradead.org with local (Exim 4.94.2 #2 (Red Hat Linux)) id 1qlmWh-001RzB-JE; Thu, 28 Sep 2023 08:37:39 +0000 Date: Thu, 28 Sep 2023 09:37:39 +0100 From: Matthew Wilcox To: Peter Zijlstra Cc: Xiaobing Li , mingo@redhat.com, juri.lelli@redhat.com, vincent.guittot@linaro.org, dietmar.eggemann@arm.com, rostedt@goodmis.org, bsegall@google.com, mgorman@suse.de, bristot@redhat.com, vschneid@redhat.com, axboe@kernel.dk, asml.silence@gmail.com, linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, io-uring@vger.kernel.org, kun.dou@samsung.com, peiwei.li@samsung.com, joshi.k@samsung.com, kundan.kumar@samsung.com, wenwen.chen@samsung.com, ruyi.zhang@samsung.com Subject: Re: [PATCH 3/3] IO_URING: Statistics of the true utilization of sq threads. Message-ID: References: <20230928022228.15770-1-xiaobing.li@samsung.com> <20230928022228.15770-4-xiaobing.li@samsung.com> <20230928080114.GC9829@noisy.programming.kicks-ass.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20230928080114.GC9829@noisy.programming.kicks-ass.net> Precedence: bulk List-ID: X-Mailing-List: io-uring@vger.kernel.org On Thu, Sep 28, 2023 at 10:01:14AM +0200, Peter Zijlstra wrote: > Now, I see what you're trying to do, but who actually uses this data? I ... don't. There seems to be the notion that since we're polling, that shouldn't count against the runtime of the thread. But the thread has chosen to poll! It is doing something! For one thing, it's preventing the CPU from entering an idle state. It seems absolutely fair to accuont this poll time to the runtime of the thread. Clearly i'm missing something.