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X-OriginatorOrg: amd.com X-MS-Exchange-CrossTenant-OriginalArrivalTime: 04 Aug 2025 08:51:36.8307 (UTC) X-MS-Exchange-CrossTenant-Network-Message-Id: 1773df83-c02b-4b6e-5c9b-08ddd3341f06 X-MS-Exchange-CrossTenant-Id: 3dd8961f-e488-4e60-8e11-a82d994e183d X-MS-Exchange-CrossTenant-OriginalAttributedTenantConnectingIp: TenantId=3dd8961f-e488-4e60-8e11-a82d994e183d;Ip=[165.204.84.17];Helo=[SATLEXMB03.amd.com] X-MS-Exchange-CrossTenant-AuthSource: BL6PEPF0001AB4A.namprd04.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Anonymous X-MS-Exchange-CrossTenant-FromEntityHeader: HybridOnPrem X-MS-Exchange-Transport-CrossTenantHeadersStamped: CH2PR12MB4214 Hello Aaron, On 7/15/2025 12:46 PM, Aaron Lu wrote: > v3: > - Keep throttled cfs_rq's PELT clock running as long as it still has > entity queued, suggested by Benjamin Segall. I've folded this change > into patch3; > - Rebased on top of tip/sched/core, commit 2885daf47081 > ("lib/smp_processor_id: Make migration check unconditional of SMP"). > > Hi Prateek, > I've kept your tested-by tag(Thanks!) for v2 since I believe this pelt > clock change should not affect things much, but let me know if you don't > think that is appropriate. I've officially tested this series so it should be fine :) In addition to Jan's test, I also did some sanity test looking at PELT and everything looks good for the simplest case - once busy loop inside a cgroup that gets throttled. The per-task throttling behavior is identical to the current behavior for this simplest case. If I find time, I'll look into nested hierarchies with wakeups to see if I can spot anything odd there. I don't really have a good control setup to compare against here but so far I haven't found anything odd and it works as intended. > > Tests I've done: > - Jan's rt deadlock reproducer[1]. Without this series, I saw rcu-stalls > within 2 minutes and with this series, I do not see rcu-stalls after > 10 minutes. > - A stress test that creates a lot of pressure on fork/exit path and > cgroup_threadgroup_rwsem. Without this series, the test will cause > task hung in about 5 minutes and with this series, no problem found > after several hours. Songtang wrote this test script and I've used it > to verify the patches, thanks Songtang. I just noticed this script. I'll give this a spin too when I test nested hierarchies. -- Thanks and Regards, Prateek