From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from frasgout.his.huawei.com (frasgout.his.huawei.com [185.176.79.56]) (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 879842940E for ; Mon, 8 Jan 2024 12:07:18 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=Huawei.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=huawei.com Received: from mail.maildlp.com (unknown [172.18.186.231]) by frasgout.his.huawei.com (SkyGuard) with ESMTP id 4T7t624kCwz6K9RQ; Mon, 8 Jan 2024 20:04:42 +0800 (CST) Received: from lhrpeml500005.china.huawei.com (unknown [7.191.163.240]) by mail.maildlp.com (Postfix) with ESMTPS id 8C43A140CB1; Mon, 8 Jan 2024 20:07:15 +0800 (CST) Received: from localhost (10.202.227.76) by lhrpeml500005.china.huawei.com (7.191.163.240) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2507.35; Mon, 8 Jan 2024 12:07:14 +0000 Date: Mon, 8 Jan 2024 12:07:13 +0000 From: Jonathan Cameron To: Dan Williams CC: Dave Jiang , , , , , Subject: Re: [PATCH v3 2/3] cxl/region: Add sysfs attribute for locality attributes of CXL regions Message-ID: <20240108120713.00005f90@Huawei.com> In-Reply-To: <65974b21859a8_8dc68294dc@dwillia2-xfh.jf.intel.com.notmuch> References: <170441200977.3574076.13110207881243626581.stgit@djiang5-mobl3> <170441210897.3574076.3084661576808646327.stgit@djiang5-mobl3> <65974b21859a8_8dc68294dc@dwillia2-xfh.jf.intel.com.notmuch> Organization: Huawei Technologies Research and Development (UK) Ltd. X-Mailer: Claws Mail 4.1.0 (GTK 3.24.33; x86_64-w64-mingw32) Precedence: bulk X-Mailing-List: linux-cxl@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit X-ClientProxiedBy: lhrpeml500003.china.huawei.com (7.191.162.67) To lhrpeml500005.china.huawei.com (7.191.163.240) On Thu, 4 Jan 2024 16:19:45 -0800 Dan Williams wrote: > Dave Jiang wrote: > > Add read/write latencies and bandwidth sysfs attributes for the enabled CXL > > region. The bandwidth is the aggregated bandwidth of all devices that > > contribute to the CXL region. The latency is the worst latency of the > > device amongst all the devices that contribute to the CXL region. > > > > Signed-off-by: Dave Jiang > > --- > > v3: > > - Make attribs not visible if no data (Jonathan) > > - Check against coord.attrib (Jonathan) > > - Fix documentation verbiage (Jonathan) > > --- > > Documentation/ABI/testing/sysfs-bus-cxl | 60 +++++++++++++++++++++++++++++++ > > drivers/cxl/core/region.c | 40 +++++++++++++++++++++ > > 2 files changed, 100 insertions(+) > > > > diff --git a/Documentation/ABI/testing/sysfs-bus-cxl b/Documentation/ABI/testing/sysfs-bus-cxl > > index fff2581b8033..86d3dbe12129 100644 > > --- a/Documentation/ABI/testing/sysfs-bus-cxl > > +++ b/Documentation/ABI/testing/sysfs-bus-cxl > > @@ -552,3 +552,63 @@ Description: > > attribute is only visible for devices supporting the > > capability. The retrieved errors are logged as kernel > > events when cxl_poison event tracing is enabled. > > + > > + > > +What: /sys/bus/cxl/devices/regionZ/read_bandwidth > > +Date: Jan, 2024 > > +KernelVersion: v6.9 > > +Contact: linux-cxl@vger.kernel.org > > +Description: > > + (RO) The aggregated read bandwidth of the region. The number is > > + the accumulated read bandwidth of all CXL memory devices that > > + contributes to the region in MB/s. Should be equivalent to > > Perhaps: > > s|Should be equivalent|It the identical data that would appear in > /sys/devices/system/node/nodeX/access0/initiators/read_bandwidth if / > when this region is onlined as memory nodeX|. > > Note that I did a s/accessY/access0/ since this data is relative to a > single Generic Port. The performance from other intiators that go > through an alternate port is not represented, right? Hi Dan, You've lost me on this comment. access0 is the access class, not enumerating a particular port etc. This interface always gives me a headache (and is at least partly my fault :(! but I think this is specifying the access characteristics from the nearest initiator (CPUs and others) to the port. access1 would be from a CPU to the port. The actual initiators are nodeY in /sys/devices/system/node/nodeX/access0/initiators/nodeY etc Jonathan