From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mgamail.intel.com (mgamail.intel.com [198.175.65.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 81F8E325489 for ; Wed, 15 Oct 2025 20:42:50 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=198.175.65.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1760560972; cv=none; b=Dl4hvbE7NtOiPbdSq1FV9y7MgbZsIWeR9FABfexO4BaSxRkqr6VADKWTuJ5trphFq/rGRUAiFHvxannFniGk5McwqUC+Ns2IT7iUxmS2ofjdl7pGCSMHZ7QW003fba5DtX2qXI8kGFPVsEGI4if9M3AorLOfyszb6QU+lsPzc2A= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1760560972; c=relaxed/simple; bh=DMcfSJEPVq5clW8pi9Lymeti7g490BgfKAvf53vb2y8=; h=Message-ID:Subject:From:To:Cc:Date:In-Reply-To:References: Content-Type:MIME-Version; b=LDpa0gmBDiuW9XP/QCgAP7f6KpVs94m+W+wooNHC26f1OmFVlAyktW4Pad17onrLKbiK4UQJvBARwPzf6aArIFdPo/5aZ4E5gR4XrRQ4FW3umiwcx25q/fNHO1IF5Y6SVJv9DA+P0iIcvv9Tnev0U4zc3hVPakm73TFZOEeb3qc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.intel.com; spf=pass smtp.mailfrom=linux.intel.com; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b=X0faGHLq; arc=none smtp.client-ip=198.175.65.18 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.intel.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.intel.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b="X0faGHLq" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1760560971; x=1792096971; h=message-id:subject:from:to:cc:date:in-reply-to: references:content-transfer-encoding:mime-version; bh=DMcfSJEPVq5clW8pi9Lymeti7g490BgfKAvf53vb2y8=; b=X0faGHLqlosUnKiaz/yNTY8QXbS3eBbGNa8phANIIdNyFLZbw7Jd9UJ9 HHpYdDg61Ep+OZIcarjS4QcdfQw2hq7OOZ3Xo3B7vheDYXgnVLTQc/A8A vHcpKJCBHET7RiBMS1X0gmz0MTlr5d0gyk5HFWmFCdisZewt3nFxT9ucs 3IHm1tF/WyCPahwB6Dj9Quq8q7JDD+l7rNBhhO42MmWpLSNt/ayIbm/yL KhESmQzVt3blHonW3l5m6RmIDV1RB2WjRhgGEH/sreza9Fxv+Ey6G7PEb Wn8/5zCpn7TnwxFSt4ef/nIhflgvMF/GPO79hIkgLmHKdwnXJzGhuuV0d w==; X-CSE-ConnectionGUID: WfciBMUnT1G4XArUnwmjTw== X-CSE-MsgGUID: cz+g1+h7SXGacvP/1bk4LA== X-IronPort-AV: E=McAfee;i="6800,10657,11583"; a="62789540" X-IronPort-AV: E=Sophos;i="6.19,232,1754982000"; d="scan'208";a="62789540" Received: from orviesa008.jf.intel.com ([10.64.159.148]) by orvoesa110.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 15 Oct 2025 13:42:50 -0700 X-CSE-ConnectionGUID: sfrKilFlShaJk24+Znnn5w== X-CSE-MsgGUID: xHVGpvbgR5CA+gZR1zORJg== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.19,232,1754982000"; d="scan'208";a="182257479" Received: from unknown (HELO [10.241.242.248]) ([10.241.242.248]) by orviesa008-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 15 Oct 2025 13:42:49 -0700 Message-ID: Subject: Re: [PATCH 09/19] sched/fair: Count tasks prefering each LLC in a sched group From: Tim Chen To: Peter Zijlstra Cc: Ingo Molnar , K Prateek Nayak , "Gautham R . Shenoy" , Vincent Guittot , Juri Lelli , Dietmar Eggemann , Steven Rostedt , Ben Segall , Mel Gorman , Valentin Schneider , Madadi Vineeth Reddy , Hillf Danton , Shrikanth Hegde , Jianyong Wu , Yangyu Chen , Tingyin Duan , Vern Hao , Len Brown , Aubrey Li , Zhao Liu , Chen Yu , Chen Yu , Libo Chen , Adam Li , Tim Chen , linux-kernel@vger.kernel.org Date: Wed, 15 Oct 2025 13:42:49 -0700 In-Reply-To: <20251015122243.GV3289052@noisy.programming.kicks-ass.net> References: <00e5f2cb6eadc3738e33858d3c4563a0775ee1c0.1760206683.git.tim.c.chen@linux.intel.com> <20251015122243.GV3289052@noisy.programming.kicks-ass.net> Autocrypt: addr=tim.c.chen@linux.intel.com; prefer-encrypt=mutual; keydata=mQENBE6N6zwBCADFoM9QBP6fLqfYine5oPRtaUK2xQavcYT34CBnjTlhbvEVMTPlNNzE5 v04Kagcvg5wYcGwr3gO8PcEKieftO+XrzAmR1t3PKxlMT1bsQdTOhKeziZxh23N+kmA7sO/jnu/X2 AnfSBBw89VGLN5fw9DpjvU4681lTCjcMgY9KuqaC/6sMbAp8uzdlue7KEl3/D3mzsSl85S9Mk8KTL MLb01ILVisM6z4Ns/X0BajqdD0IEQ8vLdHODHuDMwV3veAfnK5G7zPYbQUsK4+te32ruooQFWd/iq Rf815j6/sFXNVP/GY4EWT08UB129Kzcxgj2TEixe675Nr/hKTUVKM/NrABEBAAGJAS4EIAECABgFA k6ONYoRHQFLZXkgaXMgcmVwbGFjZWQACgkQHH3vaoxLv2UmbAgAsqa+EKk2yrDc1dEXbZBBGeCiVP XkP7iajI/FiMVZHFQpme4vpntWhg0BIKnF0OSyv0wgn3wzBWx0Zh3cve/PICIj268QvXkb0ykVcIo RnWwBeavO4dd304Mzhz5fBzJwjYx06oabgUmeGawVCEq7UfXy+PsdQdoTabsuD1jq0MbOL/4sB6CZ c4V2mQbW4+Js670/sAZSMj0SQzK9CQyQdg6Wivz8GgTBjWwWsfMt4g2u0s6rtBo8NUZG/yw6fNdao DaT/OCHuBopGmsmFXInigwOXsjyp15Yqs/de3S2Nu5NdjJUwmN1Qd1bXEc/ItvnrFB0RgoNt2gzf2 5aPifLabQlVGltIENoZW4gPHRpbS5jLmNoZW5AbGludXguaW50ZWwuY29tPokBOAQTAQIAIgUCTo3 rPAIbAwYLCQgHAwIGFQgCCQoLBBYCAwECHgECF4AACgkQHH3vaoxLv2XYdAf8DgRO4eIAtWZy4zLv 0EZHWiJ35GYAQ5fPFWBoNURE0+vICrvLyfCKTlUTFxFxTiAWHUO7JM+uBHQSJVsE+ERmTPsiUO1m7 SxZakGy9U2WOEiWMZMRp7HZE8vPUY5AM1OD0b38WBeUD3FPx5WRlQ0z6izF9aIHxoQhci0/WtmGLO Pw3HUlCy1c4DDl6cInpy/JqUPcYlvsp+bWbdm7R5b33WW2CNVVr1eLj+1UP0Iow4jlLzNLW+jOpiv LDs3G/bNC1Uu/SAzTvbaDBRRO9ToX5rlg3Zi8PmOUXWzEfO6N+L1gFCAdYEB4oSOghSbk2xCC4DRl UTlYoTJCRsjusXEy4ZkCDQROjjboARAAtXPJWkNkK3s22BXrcK8w9L/Kzqmp4+V9Y5MkkK94Zv66l XAybnXH3UjL9ATQgo7dnaHxcVX0S9BvHkEeKqEoMwxg86Bb2tzY0yf9+E5SvTDKLi2O1+cd7F3Wba 1eM4Shr90bdqLHwEXR90A6E1B7o4UMZXD5O3MI013uKN2hyBW3CAVJsYaj2s9wDH3Qqm4Xe7lnvTA GV+zPb5Oj26MjuD4GUQLOZVkaA+GX0TrUlYl+PShJDuwQwpWnFbDgyE6YmlrWVQ8ZGFF/w/TsRgJM ZqqwsWccWRw0KLNUp0tPGig9ECE5vy1kLcMdctD+BhjF0ZSAEBOKyuvQQ780miweOaaTsADu5MPGk d3rv7FvKdNencd+G1BRU8GyCyRb2s6b0SJnY5mRnE3L0XfEIJoTVeSDchsLXwPLJy+Fdd2mTWQPXl nforgfKmX6BYsgHhzVsy1/zKIvIQey8RbhBp728WAckUvN47MYx9gXePW04lzrAGP2Mho+oJfCpI0 myjpI9CEctvJy4rBXRgb4HkK72i2gNOlXsabZqy46dULcnrMOsyCXj6B1CJiZbYz4xb8n5LiD31SA fO5LpKQe/G4UkQOZgt+uS7C0Zfp61+0mrhKPG+zF9Km1vaYNH8LIsggitIqE05uCFi9sIgwez3oiU rFYgTkTSqMQNPdweNgVhSUAEQEAAbQ0VGltIENoZW4gKHdvcmsgcmVsYXRlZCkgPHRpbS5jLmNoZW 5AbGludXguaW50ZWwuY29tPokCVQQTAQgAPwIbAwYLCQgHAwIGFQgCCQoLBBYCAwECHgECF4AWIQT RofI2lb24ozcpAhyiZ7WKota4SQUCYjOVvwUJF2fF1wAKCRCiZ7WKota4SeetD/4hztE+L/Z6oqIY lJJGgS9gjV7c08YH/jOsiX99yEmZC/BApyEpqCIs+RUYl12hwVUJc++sOm/p3d31iXvgddXGYxim0 0+DIhIu6sJaDzohXRm8vuB/+M/Hulv+hTjSTLreAZ9w9eYyqffre5AlEk/hczLIsAsYRsqyYZgjfX Lk5JN0L7ixsoDRQ5syZaY11zvo3LZJX9lTw0VPWlGeCxbjpoQK91CRXe9dx/xH/F/9F203ww3Ggt4 VlV6ZNdl14YWGfhsiJU2rbeJ930sUDbMPJqV60aitI93LickNG8TOLG5QbN9FzrOkMyWcWW7FoXwT zxRYNcMqNVQbWjRMqUnN6PXCIvutFLjLF6FBe1jpk7ITlkS1FvA2rcDroRTU/FZRnM1k0K4GYYYPj 11Zt3ZBcPoI0J3Jz6P5h6fJioqlhvZiaNhYneMmfvZAWJ0yv+2c5tp2aBmKsjmnWecqvHL5r/bXez iKRdcWyXqrEEj6OaJr3S4C0MIgGLteARvbMH+3tNTDIqFuyqdzHLKwEHuvKxHzYFyV7I5ZEQ2HGH5 ZRZ2lRpVjSIlnD4L1PS6Bes+ALDrWqksbEuuk+ixFKKFyIsntIM+qsjkXseuMSIG5ADYfTla9Pc5f VpWBKX/j0MXxdQsxT6tiwE7P+osbOMwQ6Ja5Qi57hj8jBRF1znDjDZkBDQRcCwpgAQgAl12VXmQ1X 9VBCMC+eTaB0EYZlzDFrW0GVmi1ii4UWLzPo0LqIMYksB23v5EHjPvLvW/su4HRqgSXgJmNwJbD4b m1olBeecIxXp6/S6VhD7jOfi4HACih6lnswXXwatzl13OrmK6i82bufaXFFIPmd7x7oz5Fuf9OQlL OnhbKXB/bBSHXRrMCzKUJKRia7XQx4gGe+AT6JxEj6YSvRT6Ik/RHpS/QpuOXcziNHhcRPD/ZfHqJ SEa851yA1J3Qvx1KQK6t5I4hgp7zi3IRE0eiObycHJgT7nf/lrdAEs7wrSOqIx5/mZ5eoKlcaFXiK J3E0Wox6bwiBQXrAQ/2yxBxVwARAQABtCVUaW0gQ2hlbiA8dGltLmMuY2hlbkBsaW51eC5pbnRlbC 5jb20+iQFUBBMBCAA+FiEEEsKdz9s94XWwiuG96lQbuGeTCYsFAlwLCmACGwMFCQHhM4AFCwkIBwI GFQoJCAsCBBYCAwECHgECF4AACgkQ6lQbuGeTCYuQiQf9G2lkrkRdLjXehwCl+k5zBkn8MfUPi2It U2QDcBit/YyaZpNlSuh8h30gihp5Dlb9BnqBVKxooeIVKSKC1HFeG0AE28TvgCgEK8qP/LXaSzGvn udek2zxWtcsomqUftUWKvoDRi1AAWrPQmviNGZ4caMd4itKWf1sxzuH1qF5+me6eFaqhbIg4k+6C5 fk3oDBhg0zr0gLm5GRxK/lJtTNGpwsSwIJLtTI3zEdmNjW8bb/XKszf1ufy19maGXB3h6tA9TTHOF nktmDoWJCq9/OgQS0s2D7W7f/Pw3sKQghazRy9NqeMbRfHrLq27+Eb3Nt5PyiQuTE8JeAima7w98q uQ== Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable User-Agent: Evolution 3.56.2 (3.56.2-2.fc42) Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 On Wed, 2025-10-15 at 14:22 +0200, Peter Zijlstra wrote: > On Sat, Oct 11, 2025 at 11:24:46AM -0700, Tim Chen wrote: > > During LLC load balancing, tabulate the number of tasks on each runqueu= e > > that prefer a given destination LLC in a sched group. > >=20 > > For example, consider a system with 4 LLC sched groups (LLC0 to LLC3) > > balancing towards LLC3. LLC0 has 3 tasks preferring LLC3, LLC1 has > > 2, and LLC2 has 1. LLC0, having the most tasks preferring LLC3, is > > selected as the busiest source to pick tasks from. > >=20 > > Within a source LLC, the total number of tasks preferring a destination > > LLC is computed by summing counts across all CPUs in that runqueue. For > > instance, if LLC0 has CPU0 with 2 tasks and CPU1 with 1 task preferring > > LLC3, the total for LLC0 is 3. > >=20 > > These statistics allow the load balancer to choose tasks from source > > sched groups that best match their preferred LLCs. > >=20 > > Signed-off-by: Tim Chen > > --- > > kernel/sched/fair.c | 11 +++++++++++ > > 1 file changed, 11 insertions(+) > >=20 > > diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c > > index b7a68fe7601b..cbd1e97bca4b 100644 > > --- a/kernel/sched/fair.c > > +++ b/kernel/sched/fair.c > > @@ -10399,6 +10399,9 @@ struct sg_lb_stats { > > unsigned int nr_numa_running; > > unsigned int nr_preferred_running; > > #endif > > +#ifdef CONFIG_SCHED_CACHE > > + unsigned int nr_pref_llc[NR_LLCS]; > > +#endif > > }; >=20 > Hahahaha, no! We have this on-stack, this cannot be. Okay, will allocate it off stack. Tim