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Mon, 9 Feb 2026 17:08:00 +0000 (GMT) Message-ID: <113e4e4d-8b7a-437d-a3a2-de74acc9ecaa@linux.ibm.com> Date: Mon, 9 Feb 2026 18:07:59 +0100 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v13 00/18] unwind_deferred: Implement sframe handling To: Steven Rostedt , Namhyung Kim 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 , 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 References: <20260127150554.2760964-1-jremus@linux.ibm.com> <20260205135411.5fb22df2@gandalf.local.home> Content-Language: en-US From: Jens Remus Organization: IBM Deutschland Research & Development GmbH In-Reply-To: <20260205135411.5fb22df2@gandalf.local.home> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-TM-AS-GCONF: 00 X-Proofpoint-Reinject: loops=2 maxloops=12 X-Authority-Analysis: v=2.4 cv=YeCwJgRf c=1 sm=1 tr=0 ts=698a1478 cx=c_pps a=GFwsV6G8L6GxiO2Y/PsHdQ==:117 a=GFwsV6G8L6GxiO2Y/PsHdQ==:17 a=IkcTkHD0fZMA:10 a=HzLeVaNsDn8A:10 a=VkNPw1HP01LnGYTKEx00:22 a=Mpw57Om8IfrbqaoTuvik:22 a=GgsMoib0sEa3-_RKJdDe:22 a=VnNF1IyMAAAA:8 a=VwQbUJbxAAAA:8 a=1wei54M0JlXa_cUNk-YA:9 a=3ZKOabzyN94A:10 a=QEXdDO2ut3YA:10 X-Proofpoint-GUID: 6pOW16P1XhSQuI3JJirwxxHhVPPpl8Nt X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwMjA5MDE0MSBTYWx0ZWRfXyPk1TShJpjFg TRcEnZRgpTGTU6Gwj8TdWCJ3KO4QSZO01sZ3yCvl8pqdm3wyIxLYmUiMdtdy9p5YWSW34PwFfr/ cVKshdKgZpu3sjpoF2+UHdlwdcIZSEY4bs8UZ2FTjswVBBikq+mvJXupgPi1dsdSrWm9tq469eN xvgsN3MRJwzWfd5lfkZeeMK+GQOg/m/FBIH4MewmaEcyFuFZ61fOCWMEuS9WXxnTqodYhRNncZ7 WGmjiBiLu+dU4WiSl1nbTbo2YN4ZGuGWOCFVaXs+lkpEnuUo8tKKqyrHhgrhoiQBrynMFL7Ib1J ubA2JtF+UH6CwKeCbWUUWI2rXFa4c+ceaNJZV8h71qWMrHPtoz+mXQGj/FVDbszn2KIjdJW46Qd is5TOuqlE1/xaTnbuM7vcqNMwQLKP8AIdXZJw6r7GDoogA6eSKJ9Wok0CL4HdZXC96l7zkjdtR/ Ih8Qs7LVYW1HAnzx2qQ== X-Proofpoint-ORIG-GUID: O1UEHkJ3Y0btRd8FNQdSrr18n7ct04xA X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1121,Hydra:6.1.51,FMLib:17.12.100.49 definitions=2026-02-09_01,2026-02-09_03,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 suspectscore=0 adultscore=0 bulkscore=0 malwarescore=0 phishscore=0 priorityscore=1501 lowpriorityscore=0 clxscore=1015 impostorscore=0 spamscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2601150000 definitions=main-2602090141 X-Stat-Signature: wh6udb1rs7oatadpszr3ddd57o63pjy5 X-Rspam-User: X-Rspamd-Server: rspam08 X-Rspamd-Queue-Id: 258FD160005 X-HE-Tag: 1770656922-28129 X-HE-Meta: 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 csERqUjC g1UsociU8jKASFLkL6aBAFlpNIGQi6H4/3V+m4xebySxGgoqoKhjU1Ht0aIOzynsAELcQI8/X5baWfWA0TDEVjFUp3pRrwAWX1Twvx/DSWHmQRXYzzgUbwY0zW1BjUaj7qKZFTH2UBYdjAp0Y4BBqCwhaZJey8qiwPzmwSii1ECOHq32GDx5KMAgJ4mcjZxnp5OPuLKVg1S8b50iLHTiXIH0txQ+JATeU3iDZ3W8uUV7bEie9D3Dow4CxmP6BHOg5G74IgGO0X7bvvoJ/mMQJk4PI9aPxG49g1cVa7caW3a6F1dAebIKiQh3gihA20ytpfkqHQvdxFU2Ab21kgZ8AtZ5+zX8RlgdeEZRpiwymVK1aftfFhCNEzaSOLHP/blW7WVmD X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: 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). 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 IBM Data Privacy Statement: https://www.ibm.com/privacy/