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 F4214ECAAD8 for ; Tue, 20 Sep 2022 15:49:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231137AbiITPtO (ORCPT ); Tue, 20 Sep 2022 11:49:14 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49642 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230253AbiITPtL (ORCPT ); Tue, 20 Sep 2022 11:49:11 -0400 Received: from frasgout.his.huawei.com (frasgout.his.huawei.com [185.176.79.56]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A7AA869F59; Tue, 20 Sep 2022 08:49:08 -0700 (PDT) Received: from fraeml740-chm.china.huawei.com (unknown [172.18.147.200]) by frasgout.his.huawei.com (SkyGuard) with ESMTP id 4MX5XD4x8Bz67KvJ; Tue, 20 Sep 2022 23:47:24 +0800 (CST) Received: from lhrpeml500005.china.huawei.com (7.191.163.240) by fraeml740-chm.china.huawei.com (10.206.15.221) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.31; Tue, 20 Sep 2022 17:49:06 +0200 Received: from localhost (10.202.226.42) 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 15.1.2375.31; Tue, 20 Sep 2022 16:49:05 +0100 Date: Tue, 20 Sep 2022 16:49:04 +0100 From: Jonathan Cameron To: Ira Weiny CC: Dan Williams , Alison Schofield , Vishal Verma , "Ben Widawsky" , Steven Rostedt , Davidlohr Bueso , , Subject: Re: [RFC PATCH 1/9] cxl/mem: Implement Get Event Records command Message-ID: <20220920164904.00001be8@huawei.com> In-Reply-To: References: <20220813053243.757363-1-ira.weiny@intel.com> <20220813053243.757363-2-ira.weiny@intel.com> <20220824165058.00007d4f@huawei.com> <20220908135240.00001217@huawei.com> X-Mailer: Claws Mail 4.0.0 (GTK+ 3.24.29; i686-w64-mingw32) MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit X-Originating-IP: [10.202.226.42] X-ClientProxiedBy: lhrpeml500006.china.huawei.com (7.191.161.198) To lhrpeml500005.china.huawei.com (7.191.163.240) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 9 Sep 2022 13:53:55 -0700 Ira Weiny wrote: > On Thu, Sep 08, 2022 at 01:52:40PM +0100, Jonathan Cameron wrote: > > > > [snip] > > > > > > diff --git a/include/trace/events/cxl-events.h b/include/trace/events/cxl-events.h > > > > > new file mode 100644 > > > > > index 000000000000..f4baeae66cf3 > > > > > --- /dev/null > > > > > +++ b/include/trace/events/cxl-events.h > > > > > @@ -0,0 +1,127 @@ > > > > > +/* SPDX-License-Identifier: GPL-2.0 */ > > > > > +#undef TRACE_SYSTEM > > > > > +#define TRACE_SYSTEM cxl_events > > > > > + > > > > > +#if !defined(_CXL_TRACE_EVENTS_H) || defined(TRACE_HEADER_MULTI_READ) > > > > > +#define _CXL_TRACE_EVENTS_H > > > > > + > > > > > +#include > > > > > + > > > > > +#define EVENT_LOGS \ > > > > > + EM(CXL_EVENT_TYPE_INFO, "Info") \ > > > > > + EM(CXL_EVENT_TYPE_WARN, "Warning") \ > > > > > + EM(CXL_EVENT_TYPE_FAIL, "Failure") \ > > > > > + EM(CXL_EVENT_TYPE_FATAL, "Fatal") \ > > > > > + EMe(CXL_EVENT_TYPE_MAX, "") > > > > > > > > Hmm. 4 is defined in CXL 3.0, but I'd assume we won't use tracepoints for > > > > dynamic capacity events so I guess it doesn't matter. > > > > > > I'm not sure why you would say that. I anticipate some user space daemon > > > requiring these events to set things up. > > > > Certainly a possible solution. I'd kind of expect a more hand shake based approach > > than a tracepoint. Guess we'll see :) > > Yea I think we should wait an see. > > > > > > > > > > > > > > + { CXL_EVENT_RECORD_FLAG_PERF_DEGRADED, "Performance Degraded" }, \ > > > > > + { CXL_EVENT_RECORD_FLAG_HW_REPLACE, "Hardware Replacement Needed" } \ > > > > > +) > > > > > + > > > > > +TRACE_EVENT(cxl_event, > > > > > + > > > > > + TP_PROTO(const char *dev_name, enum cxl_event_log_type log, > > > > > + struct cxl_event_record_raw *rec), > > > > > + > > > > > + TP_ARGS(dev_name, log, rec), > > > > > + > > > > > + TP_STRUCT__entry( > > > > > + __string(dev_name, dev_name) > > > > > + __field(int, log) > > > > > + __array(u8, id, UUID_SIZE) > > > > > + __field(u32, flags) > > > > > + __field(u16, handle) > > > > > + __field(u16, related_handle) > > > > > + __field(u64, timestamp) > > > > > + __array(u8, data, EVENT_RECORD_DATA_LENGTH) > > > > > + __field(u8, length) > > > > > > > > Do we want the maintenance operation class added in Table 8-42 from CXL 3.0? > > > > (only noticed because I happen to have that spec revision open rather than 2.0). > > > > > > Yes done. > > > > > > There is some discussion with Dan regarding not decoding anything and letting > > > user space take care of it all. I think this shows a valid reason Dan > > > suggested this. > > > > I like being able to print tracepoints with out userspace tools. > > This also enforces structure and stability of interface which I like. > > I tend to agree with you. > > > > > Maybe a raw tracepoint or variable length trailing buffer to pass > > on what we don't understand? > > I've already realized that we need to print all reserved fields for this > reason. If there is something the kernel does not understand user space can > just figure it out on it's own. > > Sound reasonable? Hmm. Printing reserved fields would be unusual. Not sure what is done for similar cases elsewhere, CPER records etc... We could just print a raw array of the whole event as well as decode version, but that means logging most of the fields twice... Not nice either. I'm a bit inclined to say we should maybe just ignore stuff we don't know about or is there a version number we can use to decide between decoded vs decoded as much as possible + raw log? Jonathan > > Ira > > > > > Jonathan > > > >