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 D59BE3033EF; Thu, 5 Feb 2026 18:53:39 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1770317619; cv=none; b=CTImTYJrVLfy/+fOc7L8LVdrs3atNPWQHZ5hXjhknCnVdgCU42JCcJqqfyeiuamP8YF1ClstDZKKDjWzD6V6I4aXuojFFtvno0LVZe5HkvlbPBtz67Q4FInHDAEBjqMib5SrPYb9d8OzozwHBKEf2zbVNey846phJ3j6FHn5pmY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1770317619; c=relaxed/simple; bh=edmWN1Nh2COpchA+uRF1aIBilfR+WToPCXAOKu0zIog=; h=Date:From:To:Cc:Subject:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=foexaNgwMvKdZzftIxbtJcIxU/Z4FHzP7pt6PezTFBOkKhKpLyjUiwr6U3QS14/ZGtoTP4dGb+n8W4xJJr/YAn3Hpx7TKk/FrCCdX+U8OpGpE9KMA7G0k+knCvVUOVj2YhidnA6I7qY90ipCvecWhJHepPaiiHWSHiVNz0gVBm8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=QhkEJv+T; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="QhkEJv+T" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1152BC4CEF7; Thu, 5 Feb 2026 18:53:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1770317619; bh=edmWN1Nh2COpchA+uRF1aIBilfR+WToPCXAOKu0zIog=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=QhkEJv+TjVXn1Pm5yNL9fkiVmdPFmxW3fQRdGgRJq6/nyaxyxzMqWofu1h8GoeauN PyhUSpGcy3tAKIVawRN7WW1e/lfudIpUhaDs0hTROLdYO4qugbMvLy4oAMFyAg4C5d E9Z7IsprF+8905i8sLQ0fEwZYYGFv2uWkuJdEbw5hnxB1BefqZYj+gaDgBTwGIvkuI eVq/9HfypqcYX+GeKbPIPPG0iGTq0McbGi5qWBxbAoGjAlL7dbvM5FHd+dvhMGev+R HA+RZDGHwiEZmn5tTaI2S1w1t3GAtojhlPPJ4z5+6Ek3kqqKb+UNUdxsR3KIVDmZas a3TAG3vt/ByUg== Date: Thu, 5 Feb 2026 13:54:11 -0500 From: Steven Rostedt To: Namhyung Kim Cc: Jens Remus , linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org, bpf@vger.kernel.org, x86@kernel.org, linux-mm@kvack.org, Josh Poimboeuf , Masami Hiramatsu , Mathieu Desnoyers , Peter Zijlstra , Ingo Molnar , Jiri Olsa , Arnaldo Carvalho de Melo , Thomas Gleixner , Andrii Nakryiko , Indu Bhagat , "Jose E. Marchesi" , Beau Belgrave , Linus Torvalds , Andrew Morton , Florian Weimer , Kees Cook , Carlos O'Donell , Sam James , Dylan Hatch , Borislav Petkov , Dave Hansen , David Hildenbrand , "H. Peter Anvin" , "Liam R. Howlett" , Lorenzo Stoakes , Michal Hocko , Mike Rapoport , Suren Baghdasaryan , Vlastimil Babka , Heiko Carstens , Vasily Gorbik Subject: Re: [PATCH v13 00/18] unwind_deferred: Implement sframe handling Message-ID: <20260205135411.5fb22df2@gandalf.local.home> In-Reply-To: References: <20260127150554.2760964-1-jremus@linux.ibm.com> X-Mailer: Claws Mail 3.20.0git84 (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 Thu, 5 Feb 2026 10:26:10 -0800 Namhyung Kim wrote: > > Namhyung Kim's related perf tools deferred callchain support can be used > > for testing ("perf record --call-graph fp,defer" and "perf report/script"). > > Is it possible for users to choose the unwinder - frame pointer or > SFrame at runtime? I feel like the option should be > "--call-graph sframe,defer" or just "--call-graph sframe" if it always > uses deferred unwinding. Currently no, and I'm not sure we want that do we? The idea is to use the best option that is available. Why use frame pointers if sframe is available and it's being called with defer? If there's no defer, then sframes are not available, so it defaults to the best option available (which will likely be frame pointers). -- Steve