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 706B7C77B61 for ; Tue, 25 Apr 2023 00:25:17 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231332AbjDYAZQ (ORCPT ); Mon, 24 Apr 2023 20:25:16 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42452 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230355AbjDYAZP (ORCPT ); Mon, 24 Apr 2023 20:25:15 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0F2695585; Mon, 24 Apr 2023 17:25:15 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 9D86262A74; Tue, 25 Apr 2023 00:25:14 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id B3DF1C433D2; Tue, 25 Apr 2023 00:25:11 +0000 (UTC) Date: Mon, 24 Apr 2023 20:25:09 -0400 From: Steven Rostedt To: Donglin Peng Cc: mhiramat@kernel.org, linux@armlinux.org.uk, mark.rutland@arm.com, will@kernel.org, catalin.marinas@arm.com, rmk+kernel@armlinux.org.uk, palmer@dabbelt.com, paul.walmsley@sifive.com, aou@eecs.berkeley.edu, tglx@linutronix.de, dave.hansen@linux.intel.com, x86@kernel.org, bp@alien8.de, hpa@zytor.com, chenhuacai@kernel.org, zhangqing@loongson.cn, kernel@xen0n.name, mingo@redhat.com, peterz@infradead.org, xiehuan09@gmail.com, dinghui@sangfor.com.cn, huangcun@sangfor.com.cn, dolinux.peng@gmail.com, linux-trace-kernel@vger.kernel.org, loongarch@lists.linux.dev, linux-riscv@lists.infradead.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v11 0/8] function_graph: Support recording and printing the return value of function Message-ID: <20230424202509.716c6136@rorschach.local.home> In-Reply-To: References: X-Mailer: Claws Mail 3.17.8 (GTK+ 2.24.33; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-trace-kernel@vger.kernel.org On Sat, 8 Apr 2023 05:42:14 -0700 Donglin Peng wrote: > When using the function_graph tracer to analyze system call failures, > it can be time-consuming to analyze the trace logs and locate the kernel > function that first returns an error. This change aims to simplify the > process by recording the function return value to the 'retval' member of > 'ftrace_graph_ent' and printing it when outputing the trace log. > > Note that even if a function's return type is void, a return value will > still be printed, so it should be ignored. If you care about this, the > BTF file can be used to obtain the details of function return type. We > can implement a tool to process the trace log and display the return > value based on its actual type. > > Here is an example: > > I like this series, but since the merge window for 6.4 just opened, I'm going to hold off and pull this in for the 6.5 series (after a bit more review and testing). -- Steve