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 5DF3CC001E0 for ; Wed, 12 Jul 2023 12:28:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233126AbjGLM2I (ORCPT ); Wed, 12 Jul 2023 08:28:08 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47060 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233507AbjGLM2D (ORCPT ); Wed, 12 Jul 2023 08:28:03 -0400 Received: from desiato.infradead.org (desiato.infradead.org [IPv6:2001:8b0:10b:1:d65d:64ff:fe57:4e05]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id DA9B1A0; Wed, 12 Jul 2023 05:28:00 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=desiato.20200630; h=In-Reply-To:Content-Transfer-Encoding: Content-Type:MIME-Version:References:Message-ID:Subject:Cc:To:From:Date: Sender:Reply-To:Content-ID:Content-Description; bh=ZXR+7zHmkWbyYVaIYilEixXpel3+ET8rhBNIy+I7sKc=; b=burEIjw7Ax9oR6XyYXgzDOhcuF Xhtc5KYLObU41T0IENhk9G9qohZmC0Yvpb0wRw7l1oWGurx+n06gfe89pV9j1He1PowmLd8jJyW8G 6zVp1GF2gkOuSfQqmnXwyuzEsSHJpzBzRoDcraZR5u1o/H5XlxRZYWJLxZ3Q2LE0UHn9fNAfiTk55 AwKLj1j/r+rbJ4LHiTTJZlao2GGhqWJsjFEZodtwqDNEFYvFkQ0yagZeMU8KXrBVYKFvCwlCCX60H AgkXU1Hco0bnyVOotp2bryNT8o+jpABaFGlsKFzTpw66wm7t7tRLyXKz9AmKG+OeMgsd4mE9EXCCa pxRUvSiw==; Received: from j130084.upc-j.chello.nl ([24.132.130.84] helo=noisy.programming.kicks-ass.net) by desiato.infradead.org with esmtpsa (Exim 4.96 #2 (Red Hat Linux)) id 1qJYwd-003e8q-0G; Wed, 12 Jul 2023 12:27:47 +0000 Received: from hirez.programming.kicks-ass.net (hirez.programming.kicks-ass.net [192.168.1.225]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits)) (Client did not present a certificate) by noisy.programming.kicks-ass.net (Postfix) with ESMTPS id AB77B30036B; Wed, 12 Jul 2023 14:27:45 +0200 (CEST) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id 8E54B243429D2; Wed, 12 Jul 2023 14:27:45 +0200 (CEST) Date: Wed, 12 Jul 2023 14:27:45 +0200 From: Peter Zijlstra To: Geert Uytterhoeven Cc: Tejun Heo , Lai Jiangshan , "torvalds@linux-foundation.org" , Linux Kernel Mailing List , kernel-team@meta.com, Linux PM list , DRI Development , linux-rtc@vger.kernel.org, linux-riscv , netdev , Linux Fbdev development list , Linux MMC List , "open list:LIBATA SUBSYSTEM (Serial and Parallel ATA drivers)" , Linux-Renesas Subject: Re: Consider switching to WQ_UNBOUND messages (was: Re: [PATCH v2 6/7] workqueue: Report work funcs that trigger automatic CPU_INTENSIVE mechanism) Message-ID: <20230712122745.GH3100107@hirez.programming.kicks-ass.net> References: <20230511181931.869812-1-tj@kernel.org> <20230511181931.869812-7-tj@kernel.org> <20230712080504.GA3100107@hirez.programming.kicks-ass.net> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-mmc@vger.kernel.org On Wed, Jul 12, 2023 at 11:04:16AM +0200, Geert Uytterhoeven wrote: > Hoi Peter, > > On Wed, Jul 12, 2023 at 10:05 AM Peter Zijlstra wrote: > > On Tue, Jul 11, 2023 at 11:39:17AM -1000, Tejun Heo wrote: > > > I wonder whether the right thing to do here is somehow scaling the threshold > > > according to the relative processing power. It's difficult to come up with a > > > threshold which works well across the latest & fastest and really tiny CPUs. > > > I'll think about it some more but if you have some ideas, please feel free > > > to suggest. > > > > We could scale by BogoMIPS I suppose, it's a bogus measurement, as per > > the name, but it does have some relation to how fast the machine is. > > That's gonna fail miserably on e.g. ARM and RISC-V, where BogoMIPS > depends on some timer frequency. > > R-Car M2-W with 1.5 GHz Cortex-A15: 40.00 BogoMIPS > R-Car V4H with 1.8 GHz Cortex-A76: 33.33 BogoMIPS > > while the real slow 48 MHz VexRiscV gets 128 BogoMIPS. Hehe, OK, really bogus then. Lets file this idea in the bit-bucket then.