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X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?pj/R/LLr8VrACBoJYWW1Cx3cE8b375GJK/qljzPhVk9pyFslzVxHrHJIy74+?= =?us-ascii?Q?syusXt5tykmqjbX2+K8mj0xzLB8wOMHTjCyqrMgLyT8ZonrH0Ux4cCoMsWqg?= =?us-ascii?Q?9XHnW2qFp8jmrbZhJFOjtnIfFz+7cOM5pDzq71mUPxHc8PyGC6G90wAYtPjE?= =?us-ascii?Q?GXhcbGsk4SRKs7/ZpuBjYKTFM8R7ssNODIJmbxmhxE6P7h8Dyyod0I3rCamw?= =?us-ascii?Q?/m2RE28C6JDEX+/GuDiplnh+jVA+H1OvFnWmWnLpKBv419sRIzXqUjluJD22?= =?us-ascii?Q?kiiFNez9qtBLz7kywqNQrcTXZeT0HKbkCoLRhZ/td3ZhMbuV15GsH3Gv53qA?= =?us-ascii?Q?Z5anXPDigWhv9TwYvUAgOPt94WBgR6rUtKsSiyFozN+Bzp9wCon3vVVo+7wq?= =?us-ascii?Q?dFPiZmy8DiPwd17TJIcikC/Dz2Z+wJtiLTbDeS1CUSI5Fu+cSGDZa3f0pi2Q?= =?us-ascii?Q?eEK+Mcf4/E5+AAIcZrHnjg6gmQiF9aBNeDu+XLegfhOoO2BhD7sh1YcFT587?= =?us-ascii?Q?EqH3jolWGQ9/aELzCrFfT592HB5nMs7GPeabVfyYqa9f8T0s04TbEcuZUC8l?= =?us-ascii?Q?XTGlzatnt0X6x53Usvcpu3XeQx2wSAQVZpYAWBnGKJZjwzXnvJb8s7mdV0cZ?= =?us-ascii?Q?wkHhliT//GaURKI2hyty4fTcG81RMboV9BK/NBWcbDh9qnxZ82c94jeWqFFC?= =?us-ascii?Q?9Ahpsx5/GFh5KwWqj4g7CSavMlDXzS60xn/NobitQVBUPgol5+WQJwDW997p?= =?us-ascii?Q?zRUSFPKiy9MfVA1qxmp7C3chP9ce8W1YeX8rs3x0r5oQlJGN8OsbFbiqIF7Y?= =?us-ascii?Q?N27PJIf+UBNLi4blb/gT8t/LzxzL19ccT0j8CbilpL3r+pNajDtyhTYMLEYP?= =?us-ascii?Q?EYTXmsxsaHgESSAAlXwc4lDrlO/ltEY9zVCCo4E21srOTZfx8Pvsq9d2Wt2c?= =?us-ascii?Q?Pwc2GDq3U7uLDON3bKMeC3nJU19LRkakVRwb/+FG8cAFX8zO6clsNcr8GXjZ?= =?us-ascii?Q?oOsTrr1Vo4zYPS1UW6cmt9J4+BvO+GxFB8FWYRcMeu4h1B55PHJ11f6b/aMN?= =?us-ascii?Q?xrQBEfwHvEKlf0DBssdWhhFeBsgtowVUUOfWiKbEI7h4ECcAJHsU1/mq/tCQ?= =?us-ascii?Q?q8HGBDHOYGf5GMlq2HSZp18Ikdl/VsGSnZwX3sRJ4hHwzXvs+3WjCECi3LPz?= =?us-ascii?Q?gPjhnBewKs0Zi+okhxAidF38Jv5rljrY6kNijxRfwp+pzMGQY8MU1lJAerGY?= =?us-ascii?Q?2u2R2m31TgjImF7djixxsiqA8T8g8qHEG4uo5epSHfS0QbspEtXYROygAbdQ?= =?us-ascii?Q?PBc4rxj5xlvT3xhLHvC1SS5S61C8p7Kv1/IutMSKOnVBHyb6bjn0EEjnatZT?= =?us-ascii?Q?wbpNNSatkqLAUNCwbPKwbsCirBpwqopPX9tQiyABmPiOhuUJvJUuKTONXglU?= =?us-ascii?Q?0WuCpS6LTv8QmNTr9wZsF2Ard2On7Xy60J7KvhFPX9/4I/r6/qe2VVj+GSDq?= =?us-ascii?Q?Ww7MILfKHBEIWJrBofH5ofPE6Fukjoz+My5Yz4EWd94EwTpemp1U7QcC5BXz?= =?us-ascii?Q?s+UZcC6jRxLrbY3HNhq0YY34W/PuK0QXcWtF8Zn0TNKPZ+KyCHA/YfiWhW/A?= =?us-ascii?Q?jE53UdmvJGWaYzUoz+L64mj9GWJQyvEqk4ELiSRGNJh06RspUlk4fi4yZd6Y?= =?us-ascii?Q?mpcQWDj9A1IqS8KEMrPs1R2r7p8dbRxaeu+y3MReXwXiIgJgo+bBBYcwOJ09?= =?us-ascii?Q?SvDSbofwrA=3D=3D?= X-OriginatorOrg: Nvidia.com X-MS-Exchange-CrossTenant-Network-Message-Id: 98a8d713-71e7-48a5-3a06-08de8b184bf0 X-MS-Exchange-CrossTenant-AuthSource: LV8PR12MB9620.namprd12.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 26 Mar 2026 09:16:00.8979 (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: 5YVFUR0AW1gA83/cEdNbatZfkN/pA4Z1CsN/ZSbwaOGKf0WhEqiG690orc6ygpByhIuHwrZMwi3jwHul2eW8Mw== X-MS-Exchange-Transport-CrossTenantHeadersStamped: BL3PR12MB6380 On Thu, Mar 26, 2026 at 09:20:45AM +0100, Vincent Guittot wrote: > On Thu, 26 Mar 2026 at 09:12, Andrea Righi wrote: > > > > Hi Christian, > > > > On Wed, Mar 25, 2026 at 06:13:11PM +0000, Christian Loehle wrote: > > ... > > > RFT: > > > Andrea, please give this a try. This should perform better in particular > > > for single-threaded workloads and workloads that do not utilize all > > > cores (all the time anyway). > > > Capacity-aware scheduling wakeup works very different to the SMP path > > > used now, some workloads will benefit, some regress, it would be nice > > > to get some test results for these. > > > We already discussed DCPerf MediaWiki seems to benefit from > > > capacity-aware scheduling wakeup behavior, but others (most?) should > > > benefit from this series. > > > > > > I don't know if we can also be clever about ordering amongst SMT siblings. > > > That would be dependent on the uarch and I don't have a platform to > > > experiment with this though, so consider this series orthogonal to the > > > idle-core SMT considerations. > > > On platforms with SMT though asympacking makes a lot more sense than > > > capacity-aware scheduling, because arguing about capacity without > > > considering utilization of the sibling(s) (and the resulting potential > > > 'stolen' capacity we perceive) isn't theoretically sound. > > > > I did some early testing with this patch set. On Vera I'm getting much > > better performance that SD_ASYM_CPUCAPACITY of course (~1.5x avg speedup), > > mostly because we avoid using both SMT siblings. It's still not the same > > improvement that I get equalizing the capacity using the 5% threshold > > (~1.8x speedup). > > IIRC the tests that you shared in your patch, you get an additonal > improvement when adding some SMT awarness to SD_ASYM_CPUCAPACITY > compared to equalizing the capacity Yes, adding SMT awareness to SD_ASYM_CPUCAPACITY is still the apparoach that gives me the best performance so far on Vera (~1.9x avg speedup), among all those that I've tested. I'll post the updated patch set that I'm using, so we can also elaborate more on that approach as well. Thanks, -Andrea