From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 BC13F23750; Wed, 4 Oct 2023 21:42:14 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=none Received: by smtp.kernel.org (Postfix) with ESMTPSA id 5B9F1C433C8; Wed, 4 Oct 2023 21:42:13 +0000 (UTC) Date: Wed, 4 Oct 2023 17:43:21 -0400 From: Steven Rostedt To: Alan Maguire Cc: Jakub Kicinski , Johannes Berg , linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org, netdev@vger.kernel.org, linux-wireless@vger.kernel.org Subject: Re: [PATCH 0/4] tracing: improve symbolic printing Message-ID: <20231004174321.5afa2fb6@gandalf.local.home> In-Reply-To: <2f749ade-7821-00fa-ba34-e2d25cbad441@oracle.com> References: <20230921085129.261556-5-johannes@sipsolutions.net> <20231004092205.02c8eb0b@kernel.org> <20231004123524.27feeae7@gandalf.local.home> <20231004095431.1dd234e6@kernel.org> <20231004132955.0fb3893d@gandalf.local.home> <2f749ade-7821-00fa-ba34-e2d25cbad441@oracle.com> X-Mailer: Claws Mail 3.19.1 (GTK+ 2.24.33; x86_64-pc-linux-gnu) Precedence: bulk X-Mailing-List: linux-trace-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit On Wed, 4 Oct 2023 22:35:07 +0100 Alan Maguire wrote: > One thing we've heard from some embedded folks [1] is that having > kernel BTF loadable as a separate module (rather than embedded in > vmlinux) would help, as there are size limits on vmlinux that they can > workaround by having modules on a different partition. We're hoping > to get that working soon. I was wondering if you see other issues around > BTF adoption for embedded systems that we could put on the to-do list? > Not necessarily for this particular use-case (since there are > complications with trace data as you describe), but just trying to make > sure we can remove barriers to BTF adoption where possible. I wonder how easy is it to create subsets of BTF. For one thing, in the future we want to be able to trace the arguments of all functions. That is, tracing all functions at the same time (function tracer) and getting the arguments within the trace. This would only require information about functions and their arguments, which would be very useful. Is BTF easy to break apart? That is, just generate the information needed for function arguments? Note, pretty much all functions do not pass structures by values, and this would not need to know the contents of a pointer to a structure. This would mean that structure layout information is not needed. -- Steve