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dkim=none (message not signed) header.d=none;dmarc=none action=none header.from=amd.com; Received: from BL1PR12MB5320.namprd12.prod.outlook.com (2603:10b6:208:314::17) by CY3PR12MB9679.namprd12.prod.outlook.com (2603:10b6:930:100::11) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.21.546.22; Tue, 27 Oct 2026 19:12:28 +0000 Received: from BL1PR12MB5320.namprd12.prod.outlook.com ([fe80::1876:4a6d:2cf5:b8d1]) by BL1PR12MB5320.namprd12.prod.outlook.com ([fe80::1876:4a6d:2cf5:b8d1%5]) with mapi id 15.21.0546.021; Tue, 27 Oct 2026 19:12:27 +0000 Message-ID: <5135e588-0a73-4d1d-8e1e-7894e8b7089f@amd.com> Date: Tue, 27 Oct 2026 14:12:24 -0500 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v5 2/2] x86,fs/resctrl: Keep mbm_assign_mode in default mode at boot To: Reinette Chatre , tony.luck@intel.com, bp@alien8.de Cc: x86@kernel.org, Dave.Martin@arm.com, james.morse@arm.com, corbet@lwn.net, skhan@linuxfoundation.org, rdunlap@infradead.org, tglx@kernel.org, mingo@redhat.com, dave.hansen@linux.intel.com, hpa@zytor.com, kas@kernel.org, rick.p.edgecombe@intel.com, linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, linux-coco@lists.linux.dev, kvm@vger.kernel.org References: <1a8f3900e9e14ec19f5f7204fd64716eb0aa8427.1792627082.git.babu.moger@amd.com> <0082b675-5749-410c-9fec-9ce9b23b2498@intel.com> <9778fb3e-f5f8-4137-be2a-598cd44fc6f4@amd.com> <98597562-0c2c-4b32-a0b0-77777b8076c8@intel.com> Content-Language: en-US From: Babu Moger In-Reply-To: <98597562-0c2c-4b32-a0b0-77777b8076c8@intel.com> Content-Type: text/plain; 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"mbm_event" is supported but not enabled. >>>>   +b. Enable "mbm_event" mode. Switching the mbm_assign_mode may >>>> +reset all the MBM counters (and thus all MBM events) of all the resctrl groups. >>>> +:: >>>> + >>>> +  # echo "mbm_event" > /sys/fs/resctrl/info/L3_MON/mbm_assign_mode >>>>     # cat /sys/fs/resctrl/info/L3_MON/mbm_assign_mode >>>>     [mbm_event] >>>>     default >>>> >>> >>> The above changes could be merged together under a single step "a" that >>> will significantly reduce the churn when considering this is a stable patch. >> >> Yes. We can. But because of auto assign is not enabled on mode switch, we still have to touch few steps. Your choice. > > Understood. The benefit here is that the patch will only change actual information. > > Specifically, changes like the two below that just updates the letter > associated with the step: > >>>> -b. Check how many assignable counters are supported. >>>> +c. Check how many assignable counters are supported. >>>>   :: >>>>       # cat /sys/fs/resctrl/info/L3_MON/num_mbm_cntrs >>>>     0=32;1=32 Yea. This will be dropped.> > and > >>>>   -c. Check how many assignable counters are available for assignment in each domain. >>>> +d. Check how many assignable counters are available for assignment in each domain. >>>>   :: > > will be dropped from the patch. They distract from the core change and do not > seem appropriate for a patch headed to stable. Actually, the step (d) will be partially dropped as assignable counters changed from 30 to 32 without auto-assignment. # cat /sys/fs/resctrl/info/L3_MON/available_mbm_cntrs - 0=30;1=30 + 0=32;1=32 Will send the updated series later this week. Also, noticed a minor typo: - # cat /sys/fs/resctrl/mbm_L3_assignment + # cat /sys/fs/resctrl/mbm_L3_assignments Thanks Babu