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X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?qQk/9WG80UwFAwwM2vRvD5GToM+zxTEFTcrCGdCvFEbOY+dvgL8fqCqco9dH?= =?us-ascii?Q?StQvOyp09pwGCo2jKlOXuPYuuaCCmKR3X2aeqvE5Fzyczg8PZEABdf7yeN54?= =?us-ascii?Q?G46NAiV/vQrfrK+JN10sp3OJt3YZRTafwB/ApTjTjQqMVd1/QuwjG73f/DIH?= =?us-ascii?Q?0eBSA5Gse2dcB2n/PzJiZqbTJkzzjNeTc7nFjH2T1bnAbFzZKrQt2xse3crc?= =?us-ascii?Q?2K9SQ8tqhPcaXArfjlChONLfzYA67Dt9MbBfZp/6Ba5nbPeelcFcryeE779w?= =?us-ascii?Q?0Qq3zyC2NsRSiKhjzx5ZiQY1//Ayk9ulXC0GmH4xeVGxCGi7X3kG4Iwjy5rs?= =?us-ascii?Q?c90l6wiyirta/VLqCf65pyDJbQHo7Abir27VcsWdtqS0vt/hq+fY8zyZanku?= =?us-ascii?Q?0Mj9JP/jzIuegsSzelcpAXFpKRtDKa1nZ6OY/b9PfQa1mPLs3mIOdcS+wZQA?= =?us-ascii?Q?sdypnNgpUNcg3yJA2wAG1CpVvFg536fOcdsPYwzhSMJ3I1GwrUfcwEJ3CgEM?= =?us-ascii?Q?gaQvb/MI5j0sVqIpIxTEjt6nMnsXjGWDga39BzUSYlPBLvPaOrxmJisOVehx?= =?us-ascii?Q?AXsPG6os4jwEf0IDn6l5PT6sV1/0H33dW0y3pnxcGLC/mWd4EjhNP6Xp9UNY?= =?us-ascii?Q?Qyuvb7ETFmvEtkHlm4XKXDRfojIRQ5Ag7dJEJbqkFiFDEmuwiV1mO3DB/+Kp?= =?us-ascii?Q?875XodsDqvl13TZkIIXrDwT2WCO1ruoefr1lImkAvT0QocmqhdN4tRvruAqW?= =?us-ascii?Q?fyqcVkHLAd7mJd2UCaJYpNbUMLwEfIVkf3CFEvd225ja+OM6H9Ujd5V2mwmZ?= =?us-ascii?Q?f6Tns8J5DhGc9OpiUfI70MTSjC0FWxJHEqZAxAvWsfLITyhyiEjHJEUqGqQn?= =?us-ascii?Q?p47yFmlcw1ww+Auiep+hgcT4d2810mzVBv+fktNTkw2rMHg7DF3p4qfhq70c?= =?us-ascii?Q?DuRb+vcl1KKW0S66vJYOLlH4qyJ/+havuUkdp8zNEAYB2Wr+OR1sazSljZw8?= =?us-ascii?Q?TM1UtZnqpB5aQCqqhcphlhwXfW+joUL2N1GKWxbSBzA6rSAEqR7wQtQEBnhA?= =?us-ascii?Q?ZFZq7mjgPRad2oD1A0JtVRIYkAfgPSfIM/mVdHs4e2Om1gV9FH64aMCsZW64?= =?us-ascii?Q?cpPiAGqvgLCIpWsEuhZayGtZNP/MzsosLuPH9PyqDbbBd7fGQb/XY2rfjkv4?= =?us-ascii?Q?rj9cQKoADqzklKKnTtdDFSGdMK++7HAqNLOIwn4hOx7CW9jwVSPoEZgR3GvE?= =?us-ascii?Q?ALyrWMGuT3Q4BNLzNNybvF4991rDXQHwigahbSqh63t7SWalsljEKVTvBQfB?= =?us-ascii?Q?K8ekNhEeGdfyZWM48RwtJzzVZO14khjNeiP0gy29Q6V75qEDq5QIu5j/v5aP?= =?us-ascii?Q?zFWnJm7ZbyrCWSEMSKnMoPSWrQUgKJI6DRLv/mzJpMGv+NlRqQ5xNltYrdXn?= =?us-ascii?Q?nZUXDN9KGkv5CrT9DLAJkw09XTjBAP4g9wyt5GoaCQBwSvA/7gyUREapggnn?= =?us-ascii?Q?1hSHhppO2VY8mhxQH8XNXDyPX4PpiH1cI/UrlMSWxOoAr4Mkfqx+WPdZ9tFM?= =?us-ascii?Q?9MpdHegJxR3hu2jRXXveUeJwjuH/zO3hXfyozJKR+Kau7EAUAUxvEMKetb3r?= =?us-ascii?Q?hQ=3D=3D?= X-OriginatorOrg: santannapisa.it X-MS-Exchange-CrossTenant-Network-Message-Id: 5172f2e7-263c-4918-f043-08db525ad01f X-MS-Exchange-CrossTenant-AuthSource: VI1PR03MB2880.eurprd03.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 11 May 2023 20:03:39.6761 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: d97360e3-138d-4b5f-956f-a646c364a01e X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: LIn/a0J7E7h8jZE/EK7iddoL+1BvbMxabYj6trY3rVX7OrXhIsH6FTACUoeQffmx3B4pJlUiXCoYNRkocNRsCQGtF49ka1TH0ITXenmnziw= X-MS-Exchange-Transport-CrossTenantHeadersStamped: AM9PR03MB6850 Precedence: bulk List-ID: X-Mailing-List: linux-doc@vger.kernel.org Hi, first of all, thanks for your patience with my comments :) On Thu, 11 May 2023 14:34:38 -0400 Vineeth Remanan Pillai wrote: [...] > SMP GRUB paper has the equation for depreciating runtime as: > dq_i = -max{u_i, 1 - (extra_bw + Uinact)} dt > > Since we are caping at Umax, the equation would be > dq_i = -(max{u_i, Umax - (extra_bw + Uinact)} / Umax) dt (1) > > But existing implementation is: > dq_i = -max{u_i/Umax, 1 - (extra_bw + Uinact)} dt (2) > > Here in (2), we factored Umax only to the first term "u_i" and the > second term in max{} was as left as it is. What do you think? I agree with you, (1) looks more correct. I do not know why I implemented (2), but I agree with (1) now. > Now with normal DL and SCHED_FLAG_RECLAIM tasks, equation (1) can be > re-written as: > dq_i = > -(max{u_i, Ureclaim_max - (extra_bw + Uinact)}/Ureclaim_max)dt (3) > > I tested this equation (3) and it works as expected. What do you think > about the correctness of equation (3)? I agree with this too. > > I felt that, since we are using sequential reclaim mentioned in the > paper and we isolate all parameters per-cpu(except for extra_bw) we > could use the "-dq = -(U/Umax) dt" equation as it was simpler than > equation (3). This is the part I am not sure about... Maybe the best way to go is to split the patch: first you implement (1) (and use div64 to remove the approximation I used), then you implement (3) in a second patch. Finally, if removing the max{} is really needed you can do it in a third patch (but I would try to go with Equation 3 before removing the max{}) Thanks, Luca