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Thu, 30 Jul 2026 06:06:03 +0000 (GMT) Received: from [9.224.76.67] (unknown [9.224.76.67]) by smtpav03.fra02v.mail.ibm.com (Postfix) with ESMTP; Thu, 30 Jul 2026 06:06:02 +0000 (GMT) Message-ID: <18ca706f-ef45-4207-a55d-025f90133978@linux.ibm.com> Date: Thu, 30 Jul 2026 08:06:02 +0200 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [RFC v2 PATCH 0/16] Optimize this_cpu_*() ops for non-x86 (ARM64 for this series)~ To: Yang Shi , Ryan Roberts , cl@gentwo.org, dennis@kernel.org, tj@kernel.org, urezki@gmail.com, catalin.marinas@arm.com, will@kernel.org, david@kernel.org, akpm@linux-foundation.org, hca@linux.ibm.com, gor@linux.ibm.com, agordeev@linux.ibm.com Cc: linux-mm@kvack.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org References: <20260715180455.515692-1-yang@os.amperecomputing.com> <0344c559-1959-4531-9265-d5a5180eb7cd@arm.com> Content-Language: en-US From: Mete Durlu In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-TM-AS-GCONF: 00 X-Proofpoint-Reinject: loops=2 maxloops=12 X-Proofpoint-GUID: r-zTKHDUsTXOcFmf_-9wS5lhnkg_qTkD X-Proofpoint-ORIG-GUID: SOP_yvGrI1a3-1kuGNqQ95swD9gDixMk X-Proofpoint-Spam-Info: AW1haW4tMjYwNzMwMDAzOCBTYWx0ZWRfX3sdFvOaD+SK5 BwqMslyT06eKdSQz0oVVw1k7nVE1QnWBDNlUtJeG8OzEZn1Qwoo9TgP2LDtITB8K11bp8UHn33n Yi+SYqS182tCyPn3xWE9dgJhNNaRla0= X-Authority-Analysis: v=2.4 cv=dYuwG3Xe c=1 sm=1 tr=0 ts=6a6ae9d0 cx=c_pps a=bLidbwmWQ0KltjZqbj+ezA==:117 a=bLidbwmWQ0KltjZqbj+ezA==:17 a=IkcTkHD0fZMA:10 a=RAioF0-LDSMA:10 a=VkNPw1HP01LnGYTKEx00:22 a=RnoormkPH1_aCDwRdu11:22 a=U7nrCbtTmkRpXpFmAIza:22 a=VwQbUJbxAAAA:8 a=VnNF1IyMAAAA:8 a=cpGfkXA4JyvoFA7YCHUA:9 a=QEXdDO2ut3YA:10 X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwNzMwMDAzOCBTYWx0ZWRfX5gMfbafa3aqX NNjDEl9HOtJXNn4YfJJOTBdNIIC8zGhagzyCNDyk/MKfMb5upZKxisfIr4F7NvBQg1xaBcPQyNv 46vDVGcFHsZvz6oM5aox1Wu2jAQXWZi+7ZoV/5dAmfE8cDa93FDH0Re4fTtIXlnHqkmNTojKxIp MSMINRnnbCBPy0EJhnBzP4XQTVgxjMsqIuUhdnJ3diktuFy/wt7Wwp40O9F68IUluEiQXO5/7S9 eDQ9I+v86YpB6F5FwzVztmvgQV8nENbYPPyZKklzu2b+ZE9cVLNVyQ2aTkkurLiDMtUElHm0yqB 55gNYq4GxIJcsYjXQ7QUnEBwxHurFePOj6BlQTekavxxKGzzBdtYKaTJ+4C6Eza0rl68n5cy+fC ZLiVYWsF9IKSiD+qYRqfxKebYddG+4YKGZ9v8/KonRkZJYHycXOJAcJShzHh5i86D3exEA42k9e 0rkzXrDM4oGWfaDZuaQ== X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1143,Hydra:6.1.134,FMLib:17.12.100.49 definitions=2026-07-30_01,2026-07-29_01,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 impostorscore=0 clxscore=1011 phishscore=0 malwarescore=0 spamscore=0 lowpriorityscore=0 bulkscore=0 suspectscore=0 adultscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2606150000 definitions=main-2607300038 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.9.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260729_230619_459830_232DD08E X-CRM114-Status: GOOD ( 10.55 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On 22/07/2026 01:20, Yang Shi wrote: > > S390 implemented restart sequence. Heiko didn't share too much benchmark > data, just confirmed there is no regression and I had a lengthy > discussion with him (https://lore.kernel.org/ > lkml/20260520092243.264847-1-hca@linux.ibm.com/). Hi, regarding performance numbers from s390 and Heiko's implementation. It is safe to say we see noticeable improvements on micro benchmarks but nothing really pops out on regular workloads. on 24 Cores - 48 CPUs 1. Kernel Build --------------------------------------------------------------------- time make -j $(nproc) ~0-2% improvement - within noise ratio 2. stress-ng vm ops --------------------------------------------------------------------- stress-ng --vm $(nproc) --vm-bytes 128M --vm-ops 100000000 ~16% improvement on bogo/ops 3. stress-ng vm ops + fork --------------------------------------------------------------------- stress-ng -M --mmapfork $(nproc) --mmapfork-bytes 128M --mmapfork-ops 10000 ~6% improvement on bogo/ops 4. fork test --------------------------------------------------------------------- stress-ng -M --fork $(nproc) --fork-ops 10000000 ~13% improvement on bogo/ops Basecommit: a2b94afeb516 ("s390/zcrypt: Replace get_zeroed_page() with kzalloc()") Thanks, -Mete Durlu