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Fri, 23 Oct 2026 13:16:49 +0000 (GMT) Received: from li-7bb28a4c-2dab-11b2-a85c-887b5c60d769.ibm.com.com (unknown [9.39.19.68]) by smtpav04.fra02v.mail.ibm.com (Postfix) with ESMTP; Fri, 23 Oct 2026 13:16:48 +0000 (GMT) From: Shrikanth Hegde To: maddy@linux.ibm.com, linuxppc-dev@lists.ozlabs.org, peterz@infradead.org, tim.c.chen@linux.intel.com Cc: sshegde@linux.ibm.com, christophe.leroy@csgroup.eu, linux-kernel@vger.kernel.org, ritesh.list@gmail.com, kprateek.nayak@amd.com, yu.c.chen@intel.com, vineethr@linux.ibm.com, vincent.guittot@linaro.org, srikar@linux.ibm.com, npiggin@gmail.com, mpe@ellerman.id.au Subject: [PATCH v2 0/4] powerpc/topology: Introduce llc_override kernel parameter Date: Fri, 23 Oct 2026 18:46:42 +0530 Message-ID: <20261023131646.2907938-1-sshegde@linux.ibm.com> X-Mailer: git-send-email 2.54.0 X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-TM-AS-GCONF: 00 X-Proofpoint-Reinject: loops=2 maxloops=12 X-Proofpoint-Spam-Info: AW1haW4tMjYxMDIzMDA1MSBTYWx0ZWRfX1Qv7yeFQ2Ik+ hT9ZniMGpDaLa7hZZS5PDho5oSQRPf+YP7FzHQvLJWLgM/LSyxx3EMv6nBXlA1f6mf5f1L7FlX7 TuXQ6xONuAP4ZK2kswpXQB83nTZQE6M= X-Proofpoint-GUID: xgkZ0ph2K9rIvFShh5kCe0CLFO70v21W X-Proofpoint-ORIG-GUID: tkcAVau6K2n4UuIhay--Pbxct1tq9QaI X-Authority-Analysis: v=2.4 cv=UOBIjyfy c=1 sm=1 tr=0 ts=6adb5e4a cx=c_pps a=5BHTudwdYE3Te8bg5FgnPg==:117 a=5BHTudwdYE3Te8bg5FgnPg==:17 a=660iZSQnnn4A:10 a=VkNPw1HP01LnGYTKEx00:22 a=RnoormkPH1_aCDwRdu11:22 a=V8glGbnc2Ofi9Qvn3v5h:22 a=VwQbUJbxAAAA:8 a=VnNF1IyMAAAA:8 a=f8snuxdgJl2q5W0zcO8A:9 X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYxMDIzMDA1MSBTYWx0ZWRfXxv3urJTNI5YK MXwyWHpU9WzewKFMQOveglX1Z62OBfwAU/aae3KTl1K5uDQn4aXNBEWeoppqYNRMQ7yYydz/dZ1 N6dth86/3Ijsuppo8QwMdJUmKGLe0NOOZsi+rNnyIV2AjST08kUWKbB088tHdi83kUs7ud/Q6Qf cv2XrWV8sp5aCeeUe98JU6fFFW/Vn2g9yEMYEtXni04njG3TuEACRcTWwGIDlRH2+PK+sJkgQb0 d/E3JexysWlKUNLBnm9fECpeGddjXv3z8VY6AWOC7XSbnCfRtzE/XEUy8ndUCZIIJd06CWTVrAT Q6QI8XQkWDj4O/s4MW/v8nHDdN/gNJitWINcajWL91ITmQdZrYbLDS07DhpiDoyK3twaqbEjYCF V7AuBL/FU5PSnmpU0iULw/EQ72BN4jBw438isH0BttKmAYtVcj1/SICjWUdaHyjQHnTcBZSQI5E vhEUaxLVuw3+W2LboKg== X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1176,Hydra:6.1.138,FMLib:17.12.100.49 definitions=2026-10-23_03,2026-10-21_02,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 malwarescore=0 clxscore=1015 suspectscore=0 spamscore=0 priorityscore=1501 lowpriorityscore=0 adultscore=0 impostorscore=0 bulkscore=0 phishscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2610190000 definitions=main-2610230051 Provide an option for users to enable cache aware scheduling on powerpc via a command line parameter. More details of the problem and context is in cover-letter of v1. v1: https://lore.kernel.org/all/20261012102037.2477378-1-sshegde@linux.ibm.com/ v1->v2: - Move to kernel parameters from debugfs. This helps to keep llc_id consistent which doesn't change across sched domain rebuilds. (Tim Chen) - Update arch_llc_mask to reflect the override (Tim Chen) - Limit only to mc, pkg (Srikar Dronamraju) Notes: - A selftest for the functional validation of cache aware scheduling is a good idea as we discussed in v1. It is a significant change on its own and likely takes time. I am thinking it might be good idea to revisit selftests for scheduler in general. (We have very few). Maybe worth a discussion in coming OSPM. - I am on parental leave. This version is pretty much what I had last week and I haven't gotten any chance to update since. just sending it out. Sorry if I have missed to address any comments. Please expect delays in my response. Shrikanth Hegde (4): powerpc/topology: Introduce llc_override kernel parameter powerpc/topology: Update mc/pkg flags based on llc_override powerpc/topology: update arch_llc_mask based llc_override Documentation/powerpc: Add details about llc_override .../admin-guide/kernel-parameters.txt | 15 ++++ arch/powerpc/include/asm/topology.h | 8 +-- arch/powerpc/kernel/smp.c | 69 +++++++++++++++++-- 3 files changed, 81 insertions(+), 11 deletions(-) -- 2.52.0