From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp.subspace.kernel.org (Postfix) with ESMTP id CDED4145A18 for ; Thu, 2 Jan 2025 16:35:02 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=217.140.110.172 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1735835705; cv=none; b=WbOb4CnNYe77qvfR7LWEkh0BlZ8/8dbb0kF1mHr9aX5eBpIaCQYdN22tSk0O4zZWeS7cP9h4q8oNpOwwGE76h1QUU6hdIfaLrxJj1QySxtHxAtIOnO6noIgV2sB4qcjcxPMmcr8yevSnMmAHC1FD/uZLeKajWtoziuYnES2zg1w= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1735835705; c=relaxed/simple; bh=qJS7+MMQzCzx0iewRRu6tkx4CUOXaoESCJ3DbHpFWVc=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=LkTLzZ9zWlCln/Y2G1+b8VE/CwsfOxpZ76FCaRm2w7ob9b59eQqNn4Z+YPkeOfoh3qbCAZn/3u0rPNhdqJFmPFIA7nU2eW1wrQDKfDeznzdCzOFaLdfgbbvySVMe9A1QqC+gt5EScWNFzHackBVsWq3oFGI8TIvey9pIcuidYLA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com; spf=pass smtp.mailfrom=arm.com; arc=none smtp.client-ip=217.140.110.172 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=arm.com Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 4486911FB; Thu, 2 Jan 2025 08:35:30 -0800 (PST) Received: from e133380.arm.com (e133380.arm.com [10.1.197.41]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id EC5FB3F673; Thu, 2 Jan 2025 08:35:00 -0800 (PST) Date: Thu, 2 Jan 2025 16:34:58 +0000 From: Dave Martin To: Zeng Heng Cc: james.morse@arm.com, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, jonathan.cameron@huawei.com, xiexiuqi@huawei.com, "Wangshaobo (bobo)" Subject: Re: [RFC PATCH mpam mpam/snapshot/v6.12-rc1 v3 4/5] arm_mpam: Automatically synchronize the configuration of all sub-monitoring groups Message-ID: References: <20241207092136.2488426-1-zengheng4@huawei.com> <20241207092136.2488426-5-zengheng4@huawei.com> <65e556b6-61e1-7d84-ab8a-becaf55dbb18@huawei.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=us-ascii Content-Disposition: inline In-Reply-To: <65e556b6-61e1-7d84-ab8a-becaf55dbb18@huawei.com> Hi, On Fri, Dec 20, 2024 at 05:36:23PM +0800, Zeng Heng wrote: > > > On 2024/12/13 0:18, Dave Martin wrote: > > Hi, > > > > > @@ -3072,9 +3080,20 @@ struct mpam_write_config_arg { > > > static int __write_config(void *arg) > > > { > > > + int closid_num = resctrl_arch_get_num_closid(NULL); > > > struct mpam_write_config_arg *c = arg; > > > + u32 reqpartid, req_idx; > > > + > > > + WARN_ON(c->partid >= closid_num); > > > - mpam_reprogram_ris_partid(c->ris, c->partid, &c->comp->cfg[c->partid]); > > > + /* Synchronize the configuration to each sub-monitoring group. */ > > > + for (req_idx = 0; req_idx < get_num_reqpartid_per_closid(); > > > + req_idx++) { > > > + reqpartid = req_idx * closid_num + c->partid; > > > + > > > + mpam_reprogram_ris_partid(c->ris, reqpartid, > > > + &c->comp->cfg[c->partid]); > > > + } > > > return 0; > > > } > > > > I haven't decided whether this iteration belongs here or in > > mpam_resctrl.c. > > > > Your approach looks like it should work; I do it in > > resctrl_arch_update_one() instead [1], but I think the approaches are > > pretty much equivalent -- but let me know if you have any thoughts on > > it. > > > > Yes, the actual functions of these two locations are essentially the > same. However, at the __write_config position, we can reduce the > repeated judgments of cfg[partid] in mpam_update_config() and also > decrease the times of smp_call remote invocations. > > What about your option towards it? I think either can be done. I was aiming to keep things as simple as possible for now, and contain all the mapping logic in mpam_resctrl.c. I think that with my version of the code, changing the mpam_apply_config() interface to accept a PARTID range instead of a single PARTID might be a natural way to do this. This probably does make sense, in order to avoid excessive SMP cross- calling; I will have a go and see whether this works. (Note, there is likely to be redundant cross-calling already, which is one reason why I did not pay close attention to this issue. If we could batch updates separately per group of CPUs then we could reduce the number of cross-calls, though care would be needed if CPUs can be hotplugged while processing a batch of updates. I think that a change to the resctrl core interface might be necessary if we want the arch code to be able to queue and schedule updates in this way; resctrl currently assumes that each update is applied immediately.) Cheers ---Dave