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 8C568C004D4 for ; Wed, 18 Jan 2023 10:55:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229917AbjARKza (ORCPT ); Wed, 18 Jan 2023 05:55:30 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47650 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229481AbjARKxH (ORCPT ); Wed, 18 Jan 2023 05:53:07 -0500 Received: from frasgout.his.huawei.com (frasgout.his.huawei.com [185.176.79.56]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8369588752 for ; Wed, 18 Jan 2023 02:02:20 -0800 (PST) Received: from lhrpeml500005.china.huawei.com (unknown [172.18.147.201]) by frasgout.his.huawei.com (SkyGuard) with ESMTP id 4Nxgh30KRdz6J6K5; Wed, 18 Jan 2023 17:39:15 +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 15.1.2375.34; Wed, 18 Jan 2023 09:43:10 +0000 Date: Wed, 18 Jan 2023 09:43:09 +0000 From: Jonathan Cameron To: Dave Jiang CC: , , , , , Subject: Re: [RFC PATCH 2/2] cxl: Add tprintk support for header log hex dump Message-ID: <20230118094309.0000008c@Huawei.com> In-Reply-To: <0907017b-a620-0089-8d10-b3dc92e145ed@intel.com> References: <20230113154058.16227-1-Jonathan.Cameron@huawei.com> <20230113154058.16227-3-Jonathan.Cameron@huawei.com> <0907017b-a620-0089-8d10-b3dc92e145ed@intel.com> Organization: Huawei Technologies Research and Development (UK) Ltd. X-Mailer: Claws Mail 4.1.0 (GTK 3.24.33; x86_64-w64-mingw32) MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit X-Originating-IP: [10.202.227.76] X-ClientProxiedBy: lhrpeml100003.china.huawei.com (7.191.160.210) To lhrpeml500005.china.huawei.com (7.191.163.240) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-cxl@vger.kernel.org On Tue, 17 Jan 2023 11:08:26 -0700 Dave Jiang wrote: > On 1/13/23 8:40 AM, Jonathan Cameron wrote: > > May not make sense in general, but very helpful when writing multiple > > header logging support. > > > > Signed-off-by: Jonathan Cameron > > The user logging software would be retrieving from the log data directly > instead of parsing the trace output right? Will people visually inspect > the formatted trace output? Useful for debugging? Rather depends on the use case and rate of expected errors + if you are trying to debug errors before your logging infrastructure is up. Sure in production, likely these tracepoints would just get stored to a DB for later querying. But in debug, I often just use the kernel parameter to directly dump them in the main kernel log, or perf's own decoding of a trace. The nearest equivalent to this is AER which does print the log. https://elixir.bootlin.com/linux/v6.2-rc4/source/include/ras/ras_event.h#L337 though that uses __print_array so maybe that's a better choice. Don't get the nice offsets though if we do that though... I'm not fussed about this patch going upstream or not, it just makes testing patch 1 a lot easier :) Jonathan > > > --- > > drivers/cxl/core/trace.h | 7 +++++-- > > 1 file changed, 5 insertions(+), 2 deletions(-) > > > > diff --git a/drivers/cxl/core/trace.h b/drivers/cxl/core/trace.h > > index 20ca2fe2ca8e..64f6ad13529d 100644 > > --- a/drivers/cxl/core/trace.h > > +++ b/drivers/cxl/core/trace.h > > @@ -62,10 +62,13 @@ TRACE_EVENT(cxl_aer_uncorrectable_error, > > */ > > memcpy(__entry->header_log, hl, CXL_HEADERLOG_SIZE); > > ), > > - TP_printk("%s: status: '%s' first_error: '%s'", > > + TP_printk("%s: status: '%s' first_error: '%s' header_log: %s", > > __get_str(dev_name), > > show_uc_errs(__entry->status), > > - show_uc_errs(__entry->first_error) > > + show_uc_errs(__entry->first_error), > > + __print_hex_dump("", DUMP_PREFIX_OFFSET, 32, 4, > > + (char *)__entry->header_log, > > + CXL_HEADERLOG_SIZE_U32, false) > > ) > > ); > >