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b=D2vfH1t+2SNLEgNYgnXizamNj0nQQH2BWDkarlQyHg1HyCU4sppZw/kxeq6xPJN9l d0h8/Z+x4qKdbYmA60Be2WbX4Ha7Y3bmwfapyGLLWDqIyVqGJVLDKFJeGsVvBSRZ2s ICeX+MoOai2D9Jzho7z9SdmkMMrSupJyhkbQXfjJmmU5u6jq9jVq6dfulgvG1G/aWU nZMEV19yEQrczoFyQd0RDQQsJ81Xc8pMtSWtSbtgycDk6SA2S7Cymsd6UQl7Ix9Jkq Nbhhxo4JXEgJn++b1cb4hVrOLKyhSoZtvn2YOkO/EpWPoKRfRPAR+aaAgZ+IEslcHE 83Tt4p7t/SkXw== Message-ID: Date: Tue, 12 May 2026 11:02:22 +0200 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [RFC v1 PATCH 0/11] Optimize this_cpu_*() ops for non-x86 (ARM64 for this series) To: Yang Shi , cl@gentwo.org, dennis@kernel.org, tj@kernel.org, urezki@gmail.com, catalin.marinas@arm.com, will@kernel.org, ryan.roberts@arm.com, 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: <20260429170758.3018959-1-yang@os.amperecomputing.com> From: "David Hildenbrand (Arm)" Content-Language: en-US Autocrypt: addr=david@kernel.org; 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charset=UTF-8 Content-Transfer-Encoding: 7bit X-Rspamd-Server: rspam02 X-Rspamd-Queue-Id: 61D57120004 X-Rspam-User: X-Stat-Signature: 4r4875oz4saduk6a57otja6n618xxbde X-HE-Tag: 1778576548-832947 X-HE-Meta: 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 okbs0AUU xAP/2O1dmZFsmYtRi9/R8Y32H1AKfif+v4yIOEqS1NoHT9S0e3dcL9bWR5ZELlQMNDi6onh4w8oRfiFQBFfNX9S/ecoSX1NH50VxbErBT+DSbKgq1M4LgdDfpJyE4CqPtU0rvRMklbKjsXfLWJlKqWAVWnsMq0U4vqI6k8K7k8NC08dVpDHobZyDCxWRCQ9GO8BMC8yB+rXR8abMRyjI21lhmJGPeLCUiwynUiwiRxoDL/iCo/QWHG1FWmfAKXhApQWFy46pZQmkd2SOmNqdPgbKyuzhSZRPR8vhDovE40I9jZYjBj/Cs1icFBg== Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: > ========= > The benchmarks are done on 160 core AmpereOne machine. The baseline is > v7.1-rc1 kernel. > > 1. Kernel Build > --------------- > Run kernel build (make -j160) with the default Fedora kernel config in a > memcg. > 13% - 18% sys time improvment > 3% - 7% wall time improvement This is pretty impressive! There was quite some feedback during the LSF/MM session, what's the current plan? Also, it was raised that Linus so far didn't enjoy per-process page tables. Is there a way forward? Finally, in the LSF/MM session, there was the question why the preemption handling is even required. Can you describe what the problem is? -- Cheers, David