From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id E7C8D79EA for ; Fri, 21 Mar 2025 08:16:17 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.129.124 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1742544979; cv=none; b=E7g7wVDi6syLLzIZcArLkPAcbzmt2CMOlstNnqhDQnUOMs87HRB9A3wRFwqza2EI0b2cMb63+Pdmok9fNbSnzaJiyQMTt47tugNWfcdWdBePiR93ny5cgcCnatZIa9OtMXjTGLG5STtBSYMU4x3tU23eVoH/PaRY1/1SFgAGKh4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1742544979; c=relaxed/simple; bh=YLHOV03L7VuMVxa4EUpKAXdoaHrmKGwNEaOBF+8UflY=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=p6LXMaLg1g3y6feZn9WYn8PKFxeqUsNnU4vEa+C0kZVtJ1sFhC5NtgIt5AFtC1YXx7LZiZ/DAUTrsIJocJ59q/RAzWl8DnM6FBfwyczxDpeS53yrEwzUdn8/XWtWPIy/Q2IwOvd+KD2JownaomhjDbEvfqA0dPvF1ZdSk+LQqRw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=ceBZO+6g; arc=none smtp.client-ip=170.10.129.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="ceBZO+6g" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1742544976; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=nmO1kvLBJP1B2aKLuVg4GwQbIKEXPnUwaAJTPxGHvFk=; b=ceBZO+6g2fY1MjdY+8C4/MwlCfpb7/C2oTO6yfUQgh908bIcaf9U0AVguUk4J9LWSaxvna gk1zNZPXqLi19pRwGeaDMYxaGIwp0/zNkm0PdkL488pzfjbX6OZ/ZU92oviMJfx5pncvh8 FKnUzvPTm3OOPjOWvCIzuf4TNOLcmok= Received: from mx-prod-mc-04.mail-002.prod.us-west-2.aws.redhat.com (ec2-54-186-198-63.us-west-2.compute.amazonaws.com [54.186.198.63]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-517-ARr3YHa-PSWP8y_eqIY_Pg-1; Fri, 21 Mar 2025 04:16:13 -0400 X-MC-Unique: ARr3YHa-PSWP8y_eqIY_Pg-1 X-Mimecast-MFC-AGG-ID: ARr3YHa-PSWP8y_eqIY_Pg_1742544972 Received: from mx-prod-int-06.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-06.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.93]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-04.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 1C4EB18DB8C5; Fri, 21 Mar 2025 08:16:12 +0000 (UTC) Received: from pauld.westford.csb (unknown [10.45.225.99]) by mx-prod-int-06.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id B94691800370; Fri, 21 Mar 2025 08:16:08 +0000 (UTC) Date: Fri, 21 Mar 2025 09:16:04 +0100 From: Phil Auld To: Peter Zijlstra Cc: Waiman Long , Ingo Molnar , linux-kernel@vger.kernel.org, Juri Lelli , Vishal Chourasia , Vineeth Reddy , Frederic Weisbecker Subject: Re: [PATCH v2] sched/isolation: Make use of more than one housekeeping cpu Message-ID: <20250321081604.GA103187@pauld.westford.csb> References: <20250218184618.1331715-1-pauld@redhat.com> <20250305171441.GC51446@pauld.westford.csb> <521d9ec6-9aab-46d9-82e6-dab9c52970af@redhat.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <521d9ec6-9aab-46d9-82e6-dab9c52970af@redhat.com> X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.93 Hi Peter, On Fri, Mar 14, 2025 at 07:38:22PM -0400 Waiman Long wrote: > On 3/5/25 12:14 PM, Phil Auld wrote: > > On Tue, Mar 04, 2025 at 02:24:19PM +0100 Frederic Weisbecker wrote: > > > Le Tue, Feb 18, 2025 at 06:46:18PM +0000, Phil Auld a écrit : > > > > The exising code uses housekeeping_any_cpu() to select a cpu for > > > > a given housekeeping task. However, this often ends up calling > > > > cpumask_any_and() which is defined as cpumask_first_and() which has > > > > the effect of alyways using the first cpu among those available. > > > > > > > > The same applies when multiple NUMA nodes are involved. In that > > > > case the first cpu in the local node is chosen which does provide > > > > a bit of spreading but with multiple HK cpus per node the same > > > > issues arise. > > > > > > > > We have numerous cases where a single HK cpu just cannot keep up > > > > and the remote_tick warning fires. It also can lead to the other > > > > things (orchastration sw, HA keepalives etc) on the HK cpus getting > > > > starved which leads to other issues. In these cases we recommend > > > > increasing the number of HK cpus. But... that only helps the > > > > userspace tasks somewhat. It does not help the actual housekeeping > > > > part. > > > > > > > > Spread the HK work out by having housekeeping_any_cpu() and > > > > sched_numa_find_closest() use cpumask_any_and_distribute() > > > > instead of cpumask_any_and(). > > > > > > > > Signed-off-by: Phil Auld > > > > Reviewed-by: Waiman Long > > > > Cc: Peter Zijlstra > > > > Cc: Juri Lelli > > > > Cc: Frederic Weisbecker > > > > Cc: Waiman Long > > > > Cc: linux-kernel@vger.kernel.org > > > > Link: https://lore.kernel.org/lkml/20250211141437.GA349314@pauld.westford.csb/ > > > Acked-by: Frederic Weisbecker > > > > > Thanks Frederic! > > > > Anyone with commit powers willing to pick this up? > > Is this patch eligible to be merged into sched/core for the current cycle or > will have to wait until the next one? > > Thanks, > Longman > This is the patch (in this thread somewhere...) I mentioned the other day at OSPM. Thanks! Cheers, Phil --