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 X-Spam-Level: X-Spam-Status: No, score=-3.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 875B2C433ED for ; Tue, 13 Apr 2021 06:09:41 +0000 (UTC) Received: from desiato.infradead.org (desiato.infradead.org [90.155.92.199]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 3602061370 for ; Tue, 13 Apr 2021 06:09:41 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 3602061370 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.intel.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=desiato.20200630; h=Sender:Content-Transfer-Encoding :Content-Type:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:MIME-Version:Message-ID:In-Reply-To:Date:References: Subject:Cc:To:From:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=LSiCiHvYSZjSqIPXHq5z3WiVCZDJHAHlQGlI3tk0sEQ=; b=g0xem7AAXvTVl4jTqBIFH+qt7 WmorLkkXoIiPPnTIf8rDaih/sMfWcuNl9N4cbPOBMVmNKxQg2UWwpg7fxKkwKPMoN/6o8C3dGeSO+ HudOj5lawNbrqenPlk+a3VI0d8Sylx7PcQ0Z7pa7K2VGHQEbs3hLep6z3lfNahHU0BJ/Zb/Z4Em/E TixadJp7l+3V7jqSseFEmB0ty6QEoCkzdVUK2o3+kiQ5pS6LLizshPYKsxMH4u3KzuhFBy5ATEBio R0Qxa5dZekmAJX/wmyQwxOvqw/Kq3dXiM2A514vFQh7ED8lL0WDfbiYYnaB9ipjn5Wuk+nERXqpt6 kC1Qo+R9A==; Received: from localhost ([::1] helo=desiato.infradead.org) by desiato.infradead.org with esmtp (Exim 4.94 #2 (Red Hat Linux)) id 1lWCA7-008Lkh-6i; Tue, 13 Apr 2021 06:04:40 +0000 Received: from bombadil.infradead.org ([2607:7c80:54:e::133]) by desiato.infradead.org with esmtps (Exim 4.94 #2 (Red Hat Linux)) id 1lWC8t-008Lj9-W9 for linux-arm-kernel@desiato.infradead.org; Tue, 13 Apr 2021 06:03:23 +0000 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20210309; h=Content-Type:MIME-Version:Message-ID: In-Reply-To:Date:References:Subject:Cc:To:From:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=RwJ9gH6OHqmvYgO7sUIe5NHxelGc6TrOnLC3PVrS9NE=; b=ZhplxpuzBkC8uorvl2sxf1KcmC pehPjFiCfvbatI4n8ylvEkLahYCl4YIzUA+aOZIrqGNZS66LP7z78m2AxzbJgz4oFXKizQ6JaHM7i aLk1xHgmb3Y/AYhWLFcSR2ywOZQsJFskX0fjce0o/jcTGCQnSsWVgn/7djQR+3oAC1/ldh6H6tLOb DV0v97SHEpMuZRDIzjOoH7TXkIvDXvG/jqPe65606E5RBQjire5Oa0WhgDooY+59cyWPfbuuRN3YM xk3FiiC+wOyQ9ilm13tVX/XkKkyrFaHZcGiKyGAUT1ncTE/bYjl7G4FDfX6QsCsM6nGPbww9JrMf9 d4WxMdYA==; Received: from mga02.intel.com ([134.134.136.20]) by bombadil.infradead.org with esmtps (Exim 4.94 #2 (Red Hat Linux)) id 1lWC8r-006l4p-GA for linux-arm-kernel@lists.infradead.org; Tue, 13 Apr 2021 06:03:18 +0000 IronPort-SDR: rxJt3ZhaaeDCUnuCF7+KNOC2z1SEUiiQR6D+Pme7qLKkV2TmIGYuw4nFt3pVNkuxp0Kf+mcceM vOawxoIOQ5aQ== X-IronPort-AV: E=McAfee;i="6200,9189,9952"; a="181473964" X-IronPort-AV: E=Sophos;i="5.82,218,1613462400"; d="scan'208";a="181473964" Received: from fmsmga001.fm.intel.com ([10.253.24.23]) by orsmga101.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 12 Apr 2021 23:03:13 -0700 IronPort-SDR: YfsjmzNVqgEX+RdhsWjbLI5ZVirirOpsD1AM61E0QbDtRsiM7gg9190uv5YFGFNZQx9q7f3c/1 czWhBSzWKi+A== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.82,218,1613462400"; d="scan'208";a="521476626" Received: from tassilo.jf.intel.com (HELO tassilo.localdomain) ([10.54.74.11]) by fmsmga001.fm.intel.com with ESMTP; 12 Apr 2021 23:03:12 -0700 Received: by tassilo.localdomain (Postfix, from userid 1000) id D856F301AA9; Mon, 12 Apr 2021 23:03:12 -0700 (PDT) From: Andi Kleen To: Alex Kogan Cc: linux@armlinux.org.uk, peterz@infradead.org, mingo@redhat.com, will.deacon@arm.com, arnd@arndb.de, longman@redhat.com, linux-arch@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, tglx@linutronix.de, bp@alien8.de, hpa@zytor.com, x86@kernel.org, guohanjun@huawei.com, jglauber@marvell.com, steven.sistare@oracle.com, daniel.m.jordan@oracle.com, dave.dice@oracle.com Subject: Re: [PATCH v14 4/6] locking/qspinlock: Introduce starvation avoidance into CNA References: <20210401153156.1165900-1-alex.kogan@oracle.com> <20210401153156.1165900-5-alex.kogan@oracle.com> Date: Mon, 12 Apr 2021 23:03:12 -0700 In-Reply-To: <20210401153156.1165900-5-alex.kogan@oracle.com> (Alex Kogan's message of "Thu, 1 Apr 2021 11:31:54 -0400") Message-ID: <87mtu2vhzz.fsf@linux.intel.com> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/26.3 (gnu/linux) MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210412_230317_584601_096D351B X-CRM114-Status: GOOD ( 15.04 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org Alex Kogan writes: > > + numa_spinlock_threshold= [NUMA, PV_OPS] > + Set the time threshold in milliseconds for the > + number of intra-node lock hand-offs before the > + NUMA-aware spinlock is forced to be passed to > + a thread on another NUMA node. Valid values > + are in the [1..100] range. Smaller values result > + in a more fair, but less performant spinlock, > + and vice versa. The default value is 10. ms granularity seems very coarse grained for this. Surely at some point of spinning you can afford a ktime_get? But ok. Could you turn that into a moduleparm which can be changed at runtime? Would be strange to have to reboot just to play with this parameter This would also make the code a lot shorter I guess. -Andi _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel