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X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?hVDRLYyP+eIU0+1MPqqr1iagXg+MHekBvMkiLzBnT9DVxNPJPusEb8JJYkyn?= =?us-ascii?Q?4WvHMijPxcfhlGYTsQtdfJs80/Gy09adHsOK4O562B7dRv13SPLotQMnUUZu?= =?us-ascii?Q?Fvpe7ABeYJMh86LUEbKxXpjCnohLr0DMyeeGfVvpdt2zNVidUY+7bwZ4yQ9q?= =?us-ascii?Q?6jjQgziUiGXf47NwA8U2Hi7i74bG3cV9B2+rs8848usrzq/cwn8WU9Vc/xN1?= =?us-ascii?Q?MYyqe9tcrft25DucjlzuxKvYgx9djtiXwDUiQx8xiVLLIB1lle19l/DL5EY8?= =?us-ascii?Q?/6it7s7rHdvL32F4wvwRm8jeVOOzSHz7xlKZc4xKe6rPBNcgVFsD4sSpn12q?= =?us-ascii?Q?z7VH3qv1i+YUGJ/W66/JMZccIs/q0RM7D2148CglO0uaNvfW836XbC5bbTqL?= =?us-ascii?Q?vZ2K/+wqhq6gkQfscjrMNMLSc4nzRGeCG5D/hCN2y+QwJ6YFITm81mGtr3SH?= =?us-ascii?Q?o/dMtPU33zqrZjCaTPeRZf+xl12CxcAcYVYTCCFt3xHT72DEzeB4VTlzYwf1?= =?us-ascii?Q?oLst/oz7aNvR8peqFL3DlumTHsHUSvNsoJ4BQJVTNmBaLp5CkArbJNRveHnj?= =?us-ascii?Q?ECk+bkCC5txtf4BYW+H9amWoYO5elk2mAAUB5BLjEFmJmMzEu7MyR8CBsoTW?= =?us-ascii?Q?RZ89XeBI/f+mfj7xr9iYSaYnfN1vYVydtAgLck/lnYv1kCB15EQc/hQ93600?= =?us-ascii?Q?vnsn4VQoWyyBvFoZlSgYzQj7pknZJyTL/AR1gSdxEV0WRUdY2OkQc009LNVM?= =?us-ascii?Q?Od7k0yA54lx/ZPWW+gWq42QH5ftQl9KSHjhw7uk4Ak3rbloClomsEpXgLEON?= =?us-ascii?Q?rnkSjJhVgUi/JRzdUGRFRPb48keSpzXzZ0vXLLoN4AEXUiPYgbnABWS+iawB?= =?us-ascii?Q?zECnAPN/CioMHQJtj4mBzrPqT61mK3Vq8moB1gZn+VUFIxyWoPHGTix7vs3H?= =?us-ascii?Q?0FxCDzGg/JhaliPHb6raUbWCBrvfm1NBAqGOmxFCBCGZb4fsJG14T2HcBTfC?= =?us-ascii?Q?+DxZRDpL659+ec3SjeHqcrFXb94cozF3dwh+dCbYHQWklIqe3+Egwx+UWGxU?= =?us-ascii?Q?EpfzE1G0v+YP5KEcCLJLcyHWID0ETp+cMX61DGkrNAcvXQpKfQIIwPlMA78F?= =?us-ascii?Q?AWwDCSv0JnleECHe+JyFD/QtuLTmoOMS34lVddaiidsjuONQQ4TizJeXlocQ?= =?us-ascii?Q?Ibgls7YvSU5bJX70AiWbGF2M0A0yZG5y8gus4Ve+agIsBEu7RWZ4Kav2qLQK?= =?us-ascii?Q?78Nj99FVSfx5SVceeB0kqpgXkQHkhI3HgKk9cD04ciHEF05Y97XdwKPCDVqK?= =?us-ascii?Q?2WQjA7yx5oCTzpFn1aufYXa+WE6ZPjEda/yS3etlRiNTh1mwn7IJhHOtctE6?= =?us-ascii?Q?/QNwDfiHQfHx3OLHRWz4YzXh/Vw4sJlkBAwQjkKnp6rPYiULfUpZb2CadRxl?= =?us-ascii?Q?lkbvSYCzsGiKIkKaLUQ0LDK3znh0QBG69OezCASwGeIa3HhXEztn31rnx6AM?= =?us-ascii?Q?bNNtnvpWRNTZCgc3X/j1HzA47c1xq3HlQlXpdX2l/gKqLq1MpAnw/y+cF8OP?= =?us-ascii?Q?FuPNnxPXQpKQzm/Mh0kY5vwz4c95XjTKoFG8BoqO?= X-OriginatorOrg: Nvidia.com X-MS-Exchange-CrossTenant-Network-Message-Id: 60324f8f-da94-47bc-14e8-08dd47400985 X-MS-Exchange-CrossTenant-AuthSource: CY5PR12MB6405.namprd12.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 07 Feb 2025 06:24:12.0829 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: 43083d15-7273-40c1-b7db-39efd9ccc17a X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: 2dI5WL3cC0Ka/qn656pSWb/kyavunDyE5eCGc+v5bTnWkvb7rM8t8/3DidLlJUdVF1CrZzSzcb+DcIRjsPubeQ== X-MS-Exchange-Transport-CrossTenantHeadersStamped: PH8PR12MB6892 Hi, On Fri, Feb 07, 2025 at 12:13:36PM +0900, Changwoo Min wrote: > This patchset introduces a new event, SCX_EV_ENQ_SLICE_DFL, and updates > two scx schedulers -- scx_qmap and scx_central -- to print out the new > event. > > SCX_EV_ENQ_SLICE_DFL counts how many times the tasks' time slice is set > to the default value (SCX_SLICE_DFL) by the sched_ext core in the enqueue > and pick_next paths. > > Scheduling a task with SCX_SLICE_DFL unintentionally would be a source > of latency spikes because SCX_SLICE_DFL is relatively long (20 msec). > Thus, soaring the SCX_EV_ENQ_SLICE_DFL value would be a sign of BPF > scheduler bugs, causing latency spikes. Not directly related to this patch set, but as a general thought: would it be useful to introduce ops->slice_ms (in sched_ext_ops) to override SCX_SLICE_DFL? With that, schedulers that care about latency could set a smaller default time slice to prevent potential spikes caused by the implicit use of SCX_SLICE_DFL. Opinions? -Andrea > > Changwoo Min (2): > sched_ext: Add an event, SCX_EV_ENQ_SLICE_DFL > sched_ext: Print an event, SCX_EV_ENQ_SLICE_DFL, in scx_qmap/central > > kernel/sched/ext.c | 15 ++++++++++++++- > tools/sched_ext/scx_central.bpf.c | 2 ++ > tools/sched_ext/scx_qmap.bpf.c | 2 ++ > 3 files changed, 18 insertions(+), 1 deletion(-) > > -- > 2.48.1 >