From: Jens Remus <jremus@linux.ibm.com>
To: Steven Rostedt <rostedt@kernel.org>, Namhyung Kim <namhyung@kernel.org>
Cc: linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org,
bpf@vger.kernel.org, x86@kernel.org, linux-mm@kvack.org,
Josh Poimboeuf <jpoimboe@kernel.org>,
Masami Hiramatsu <mhiramat@kernel.org>,
Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
Peter Zijlstra <peterz@infradead.org>,
Ingo Molnar <mingo@kernel.org>, Jiri Olsa <jolsa@kernel.org>,
Arnaldo Carvalho de Melo <acme@kernel.org>,
Thomas Gleixner <tglx@linutronix.de>,
Andrii Nakryiko <andrii@kernel.org>,
Indu Bhagat <indu.bhagat@oracle.com>,
"Jose E. Marchesi" <jemarch@gnu.org>,
Beau Belgrave <beaub@linux.microsoft.com>,
Linus Torvalds <torvalds@linux-foundation.org>,
Andrew Morton <akpm@linux-foundation.org>,
Florian Weimer <fweimer@redhat.com>, Kees Cook <kees@kernel.org>,
"Carlos O'Donell" <codonell@redhat.com>,
Sam James <sam@gentoo.org>, Dylan Hatch <dylanbhatch@google.com>,
Borislav Petkov <bp@alien8.de>,
Dave Hansen <dave.hansen@linux.intel.com>,
David Hildenbrand <david@redhat.com>,
"H. Peter Anvin" <hpa@zytor.com>,
"Liam R. Howlett" <Liam.Howlett@oracle.com>,
Lorenzo Stoakes <lorenzo.stoakes@oracle.com>,
Michal Hocko <mhocko@suse.com>, Mike Rapoport <rppt@kernel.org>,
Suren Baghdasaryan <surenb@google.com>,
Vlastimil Babka <vbabka@suse.cz>,
Heiko Carstens <hca@linux.ibm.com>,
Vasily Gorbik <gor@linux.ibm.com>
Subject: Re: [PATCH v13 00/18] unwind_deferred: Implement sframe handling
Date: Mon, 9 Feb 2026 18:07:59 +0100 [thread overview]
Message-ID: <113e4e4d-8b7a-437d-a3a2-de74acc9ecaa@linux.ibm.com> (raw)
In-Reply-To: <20260205135411.5fb22df2@gandalf.local.home>
On 2/5/2026 7:54 PM, Steven Rostedt wrote:
> On Thu, 5 Feb 2026 10:26:10 -0800
> Namhyung Kim <namhyung@kernel.org> 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).
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"?
Regards,
Jens
--
Jens Remus
Linux on Z Development (D3303)
jremus@de.ibm.com / jremus@linux.ibm.com
IBM Deutschland Research & Development GmbH; Vorsitzender des Aufsichtsrats: Wolfgang Wendt; Geschäftsführung: David Faller; Sitz der Gesellschaft: Ehningen; Registergericht: Amtsgericht Stuttgart, HRB 243294
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next prev parent reply other threads:[~2026-02-09 17:08 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-01-27 15:05 Jens Remus
2026-01-27 15:05 ` [PATCH v13 01/18] unwind_user/sframe: Add support for reading .sframe headers Jens Remus
2026-01-27 15:05 ` [PATCH v13 02/18] unwind_user/sframe: Store .sframe section data in per-mm maple tree Jens Remus
2026-01-27 15:05 ` [PATCH v13 03/18] x86/uaccess: Add unsafe_copy_from_user() implementation Jens Remus
2026-01-27 15:05 ` [PATCH v13 04/18] unwind_user/sframe: Add support for reading .sframe contents Jens Remus
2026-01-27 15:05 ` [PATCH v13 05/18] unwind_user/sframe: Detect .sframe sections in executables Jens Remus
2026-01-27 15:05 ` [PATCH v13 06/18] unwind_user/sframe: Wire up unwind_user to sframe Jens Remus
2026-01-27 15:05 ` [PATCH v13 07/18] unwind_user: Stop when reaching an outermost frame Jens Remus
2026-01-27 15:05 ` [PATCH v13 08/18] unwind_user/sframe: Add support for outermost frame indication Jens Remus
2026-01-27 15:05 ` [PATCH v13 09/18] unwind_user/sframe: Remove .sframe section on detected corruption Jens Remus
2026-01-27 15:05 ` [PATCH v13 10/18] unwind_user/sframe: Show file name in debug output Jens Remus
2026-01-27 15:05 ` [PATCH v13 11/18] unwind_user/sframe: Add .sframe validation option Jens Remus
2026-01-27 15:05 ` [PATCH v13 12/18] unwind_user: Enable archs that pass RA in a register Jens Remus
2026-01-27 15:05 ` [PATCH v13 13/18] unwind_user: Flexible FP/RA recovery rules Jens Remus
2026-01-27 15:05 ` [PATCH v13 14/18] unwind_user: Flexible CFA " Jens Remus
2026-01-27 15:05 ` [PATCH v13 15/18] unwind_user/sframe: Add support for SFrame V3 flexible FDEs Jens Remus
2026-01-27 15:05 ` [PATCH v13 16/18] unwind_user/sframe: Separate reading of FRE from reading of FRE data words Jens Remus
2026-01-27 15:05 ` [PATCH v13 17/18] unwind_user/sframe/x86: Enable sframe unwinding on x86 Jens Remus
2026-01-27 15:05 ` [PATCH v13 18/18] unwind_user/sframe: Add prctl() interface for registering .sframe sections Jens Remus
2026-02-05 18:26 ` [PATCH v13 00/18] unwind_deferred: Implement sframe handling Namhyung Kim
2026-02-05 18:54 ` Steven Rostedt
2026-02-09 17:07 ` Jens Remus [this message]
2026-02-11 0:17 ` Namhyung Kim
2026-02-11 1:47 ` Dylan Hatch
2026-02-11 16:15 ` Jens Remus
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