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X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?r3WxvIuJxy706jYp1BLPVKtSRt+kj3DqknJ8aS7hkIx02WpRqE8Yj8v8KRzD?= =?us-ascii?Q?gLrGUofRxd5IVIkthslCvIDWmr+Fyadc1ZywyGHM6HxfCkMtcmC3FSQFhqJK?= =?us-ascii?Q?er0rPMew+cTKwY3dRpyuXuRkTYCj/VQuq0EVye/uAOpD2dHGdiVhf0kwPn4J?= =?us-ascii?Q?8vtfmflWNEzRHalNPibDF9G7EfzKYSc1y4QiPpkxljjH6oJvHNjX8VJxYEBP?= =?us-ascii?Q?d7/obQgsTQInOpHI4XmlKyJS5BxjtkIk/bIcn1zEWWtswNIbmJaWVDfyPkRN?= =?us-ascii?Q?w1gUsb9noRTMSrO+61/C6ZiMVsSht23trjoipOKF/ekwE3wdTiafOm0iE8xu?= =?us-ascii?Q?h1fQh3sHbzh3J/SJ3lrTK24HTsml5uELxRCGZH6f7mGY8Qr55RvNp+U2RT3S?= =?us-ascii?Q?6IitGaAJscpQYwJdGfF5NAwbtjNfqoH5ECndJ+FVsuihyNk6eLwVqfj+MZ7D?= =?us-ascii?Q?1Iqbsc9tbXfc8ga1eYtgZ+GfZPndN2+7403yj/evxTuOY1urkJ1K988E/O/9?= =?us-ascii?Q?KA56FZx3fQMzHJuGKWThQSEtxUCpFpPRvZyIMHVCNsv5Aa/ubHgvqMrbUbRB?= =?us-ascii?Q?AIU9R4FtNfcouUS7sm+ijRZoh1zoAkaHizSUoM84q1zWuxpbhY0D5iWfNXwo?= =?us-ascii?Q?PRO30T+TzL/5xuTknxpdHbk42cz3diBZWQnD7RWvqw2i0A+6lCSPBHWgd8r7?= =?us-ascii?Q?j9YiSiXOMWWLRmuMGV73efcAPgFchhK9qkxaqa5p+SI+acvpuAjzNDzTPX+7?= =?us-ascii?Q?Wv2BwiBlUwjnuaeJErqFnjBh9zu7bC/n6HVUJAjYTfdokPRPUtmUszApKMpu?= =?us-ascii?Q?1kj+kGxvio3MCjKzwdWgybF0j9skgZ5NYx/JSIv11pTocdp/i/0FgLHIdzaP?= =?us-ascii?Q?Vs6vl+OAIMegUfPUj3kM65Z/TUB3wovS+nkrYjYvdQLJcE2YHv3wYSH0dH9h?= =?us-ascii?Q?T0Xnl6v/E0qNl+/cZG5zSpO65Dl+ZZr9O7eT7ezIt4e6e0HnWBmzt9p8XDXn?= =?us-ascii?Q?ejidYmc3YhA8hdW89q04sgZ4JHD7ko3OhygJaLwgiRmN/dqjBLgTuKHIpJgm?= =?us-ascii?Q?z3v+JgS4B/201jPmHbGsclp85LI+yR4eQ62c3iUSzfZGu5H7klOMu6LlCE88?= =?us-ascii?Q?nqyZGrz7dZeUPAysgu/veKizPyQO+gzSOanoPAL3qwIZl2P2zPRDglPJKLyw?= =?us-ascii?Q?Tnko5grmYHF0mIn4AR1MAr3hlHX99+Cyv1dTO/tIj+EI40mbvQ4Ce5vvlnpM?= =?us-ascii?Q?K4p5prXlwC64k0BgdhMEaZ4Y7p/uFOuG+6pOy8sBo11TKjrGxYXvgZmlR8E7?= =?us-ascii?Q?vgmDC+GlNUEGx7btMxG7345HN19t17sVruy1o81P3bp7ryXvdeIN2x3QHVAT?= =?us-ascii?Q?jD1rRd4aVXjGvwDxzwzMPb9ewueR6Cf4IzFVgHB40Iy583IzfwOPCKw8UykL?= =?us-ascii?Q?atRMSrTvPzB5i/VHO3yN00ewDPoUZS7ehnF8dkfpgj/GczjE/B/wzKwLDNOf?= =?us-ascii?Q?oUfyxPepgF1vzN/3U+WE4crjLwUuovHQoGnA6KeX1CUUiBmv2Xpvs9ZLTYru?= =?us-ascii?Q?vlIVFbyiVtgHVvkAsAjj+VtBEiAjTp6Pc3YZtB4u?= X-OriginatorOrg: Nvidia.com X-MS-Exchange-CrossTenant-Network-Message-Id: 05aa719c-0143-4390-8d44-08dd4744157b X-MS-Exchange-CrossTenant-AuthSource: CY5PR12MB6405.namprd12.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 07 Feb 2025 06:53:10.1146 (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: vP8Fg2rFa+QGBAOyJl2YuENfWFrqnhaQoGZ8TgngXLP8nXQjif/37ffUlUMsCKzO0N6QATNSE8D+M4g/XUWjOQ== X-MS-Exchange-Transport-CrossTenantHeadersStamped: CH0PR12MB8529 On Fri, Feb 07, 2025 at 03:49:24PM +0900, Changwoo Min wrote: > Hello, > > On 25. 2. 7. 15:24, Andrea Righi wrote: > > 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? > > That sounds like a good idea! Alright, I'll send a patch after this one is applied. Thanks, -Andrea > > Regards, > Changwoo Min