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 5FFA51C5D5E; Wed, 11 Feb 2026 00:17:49 +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=1770769069; cv=none; b=NQ34veoB0g86gC4DSTEDCVXbulbSPdurY756szbhjNgJCTqO0yqrvfEy/Rkgttc6z2ch/3zufaTINl4Qjy9nzzvxIzDRlHU6Dn63hHKezd+6EeSPzR+ofi1WAxSfIyBvg+IoQE7lq5AmKj93IZ5ihMUYKGMucYZzzyGF2Gd+QM8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1770769069; c=relaxed/simple; bh=X/PX6FbL34s4xBDSZ/RSuiPyyQFzkoB8wVlhJlcXfNE=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=MwdpotgUwQ5agP2sbFNXf3mDLV/5LExJVY5rcg1//OomBZdip2yltr9UKD8nFLOlZMeHVb9Eh4QtMlUjRNJWKExWUrcgZz2/B13/Xn/GDcWNKKJB17sIC0IBXQgUJecC94D9NFcVpicDb//vztuNFF53Ql524YynJBIok99EMow= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=d3fBm5Gv; 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="d3fBm5Gv" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 8D7E0C116C6; Wed, 11 Feb 2026 00:17:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1770769069; bh=X/PX6FbL34s4xBDSZ/RSuiPyyQFzkoB8wVlhJlcXfNE=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=d3fBm5GvY71c46Z3yyUGu+knRQsYtlO5acDvD8eb13R8BszofgVIMcbhTiBqShC9j MGZNauvOVF56+3fYEW97TuWq+7OD0vYBzw8f1POL47D7+I2V0YVc5x1d2Vc8UdDxIq tHatD8oxuZOMW5QfnIogRP4pCr7LrJjCX8mimi5Ji3h5y4t5IiEvaAhE+0A7AWl4zq gPPWSULN9qiU0gGtb21aSxTUtSy+/2BYMPSB8AV+P2VH8qNy9DhFUw/v9B/2XBaPY9 cr9cVvNq/TqEtAOygG4DS0oTDFY6qUdQbfiMwzLkhTEGk3GXQMae5eh8Uy9n9TGtxB 3T+LQYaWYipBw== Date: Tue, 10 Feb 2026 16:17:46 -0800 From: Namhyung Kim To: Jens Remus Cc: Steven Rostedt , 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: References: <20260127150554.2760964-1-jremus@linux.ibm.com> <20260205135411.5fb22df2@gandalf.local.home> <113e4e4d-8b7a-437d-a3a2-de74acc9ecaa@linux.ibm.com> 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=utf-8 Content-Disposition: inline In-Reply-To: <113e4e4d-8b7a-437d-a3a2-de74acc9ecaa@linux.ibm.com> Hello, On Mon, Feb 09, 2026 at 06:07:59PM +0100, Jens Remus wrote: > On 2/5/2026 7:54 PM, Steven Rostedt wrote: > > 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). Users (me, at least) may want to compare stacktraces from FP and SFrame? > > Maybe it would make sense not to "overload" the perf record option > "--call-graph fp,defer" and use it for all deferred unwinding methods. > > What about "--call-graph defer", "--call-graph any,defer", or > "--call-graph *,defer"? Sounds better. But I think it cannot enforce "--call-graph fp,defer" to use frame pointers when SFrame is available.. Hmm. Thanks, Namhyung