From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from sender4-pp-o92.zoho.com (sender4-pp-o92.zoho.com [136.143.188.92]) (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 411E035F199 for ; Mon, 13 Jul 2026 05:01:55 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=pass smtp.client-ip=136.143.188.92 ARC-Seal:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783918916; cv=pass; b=GZGtWjDIrr5WMIt7qcvJmJY1i3JNwT7kjBgY4ShMh17R8BEAYv1QamF0uXWQ19OY+vDJL0rY7p17hxOclRxpyuKaR67guRNfHl56iOHw4tv9qUUUBq3O/HqXwh+xMmClg65Irb/JMkQy5rXr/Az1C73IYuC4oiFXFXSVvutuO8E= ARC-Message-Signature:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783918916; c=relaxed/simple; bh=+g+Ha32aE46YWwbyAPjzDLUQ5uUxW32HPgT0D5vFdM4=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=QFLv9rISnwYP2QrPR2hBCa609bdcVoSUaiIBHdGuKrSF9f6vQ3Ey6Yv7II9fy6btZI0VTQ3HYls5wWnvYn05xloMqXEu/nUTFZTxps8aXQSptq5C5XnFMhintTR0qD95bPQ8pN+Js+sarx9MJWMD6MAk+qKJY/rYxjHS7tvBGg4= ARC-Authentication-Results:i=2; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=zohomail.com; spf=pass smtp.mailfrom=zohomail.com; dkim=pass (1024-bit key) header.d=zohomail.com header.i=kingxukai@zohomail.com header.b=bOPQUA11; arc=pass smtp.client-ip=136.143.188.92 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=zohomail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=zohomail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=zohomail.com header.i=kingxukai@zohomail.com header.b="bOPQUA11" ARC-Seal: i=1; a=rsa-sha256; t=1783918883; cv=none; d=zohomail.com; s=zohoarc; b=LOCGCUacU3WTMx5k2PMeVzb0rodCKvTlcjJyPUjqh2D3uHFFDHUnC32RhBD1MwzN4FjWE6cGG2MQEE2oVUzvXgZKYNmaEKpPYKniaPixiorYgICYXUuPiRccL4ZapMPMuCTkW45p0ZZKJl4h61JCES1RX/CHXAJZbgMDI0XTFCU= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zohomail.com; s=zohoarc; t=1783918883; h=Content-Type:Content-Transfer-Encoding:Cc:Cc:Date:Date:From:From:In-Reply-To:MIME-Version:Message-ID:References:Subject:Subject:To:To:Message-Id:Reply-To; bh=k0Mkce7E1+aMx/3TJrumyCmKzQujX4pfry+w12HW060=; b=Eb3HIzokZulOxiwjvfQ3PJoJ5pAxJNmMUg3qMWO7FPKmhlpwaq8MGFH1W+jOP+rQcV8P7N7MWDP6hR9XckZ/9MjPQKXNSXElkXnM+Dl9fvLmctvWGVKBV+hKUymC8tBFZ6oTTYoG3PT5kcnJLEGjGfEYhON+P+V/hIIPiY9IIyY= ARC-Authentication-Results: i=1; mx.zohomail.com; dkim=pass header.i=zohomail.com; spf=pass smtp.mailfrom=kingxukai@zohomail.com; dmarc=pass header.from= DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; t=1783918883; s=zm2022; d=zohomail.com; i=kingxukai@zohomail.com; h=Message-ID:Date:Date:MIME-Version:Subject:Subject:To:To:Cc:Cc:References:From:From:In-Reply-To:Content-Type:Content-Transfer-Encoding:Feedback-ID:Message-Id:Reply-To; bh=k0Mkce7E1+aMx/3TJrumyCmKzQujX4pfry+w12HW060=; b=bOPQUA11P8T7FSrV57ciiQgFH6q6FE7VvOBUcl4yVp0wVUUEEb8T+sm/zCSHFs+K s+pQmiXwQvWnLoMb5mF6S8ggdTzjZGM5Dw/0CrbTYzlnKPPvyKaqWb2rWFzcfIqyDID jTeHzf3hAkSbXdEDLDB6VHB6QIgcMkQjWWLrOupQ= Received: by mx.zohomail.com with SMTPS id 1783918879837969.1100651355305; Sun, 12 Jul 2026 22:01:19 -0700 (PDT) Message-ID: <637f7ce3-e7d4-47d2-9aa8-b3faabdb59e7@zohomail.com> Date: Mon, 13 Jul 2026 13:01:07 +0800 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH RFC] sched/proxy: Defer donor commit until after proxy resolution To: K Prateek Nayak , John Stultz , Ingo Molnar , Peter Zijlstra , Juri Lelli , Vincent Guittot , Dietmar Eggemann , Steven Rostedt , Ben Segall , Mel Gorman , Valentin Schneider Cc: linux-kernel@vger.kernel.org References: <20260707-sched-proxy-v1-0-5928bf6dedf0@zohomail.com> <20260707-sched-proxy-v1-1-5928bf6dedf0@zohomail.com> <47c5e555-92ce-4ab1-8adf-c10639753b49@zohomail.com> <30ac52e7-3058-42f4-8f20-ff466716e9a5@amd.com> From: Xukai Wang Content-Language: en-US In-Reply-To: <30ac52e7-3058-42f4-8f20-ff466716e9a5@amd.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Feedback-ID: zu080112270115e2b7df64b5ec6a5250ce000088bcd21dcdd123ee9ad5ee0570cbf2c63454e1e4a620611510:ZohoMail X-Zoho-CM-AccountID: 2ee5dd3c83366259b2ba1e9826250ffebed1ef2dd213857d649ad25aba73b429 X-ZohoMailClient: External Hi Prateek, On 2026/7/13 12:22, K Prateek Nayak wrote: > Hello Xukai, > I've added John on this thread in case he knows of any dependency > in the find_proxy_task() bits that rely on rq->donor being updated > with the recent pick (I, personally am not aware of any but there > might be some dependency that eventually gets added with the full > proxy series that I haven't yet considered). Thanks for taking a look and looping John in. >> In that run, I got: >> find_call 5407 >> find_success 523 >> find_idle 1660 >> find_null 3224 >> >> spec_commit_blocked 5407 >> spec_commit_then_null 3224 >> spec_commit_then_idle 1660 >> spec_commit_then_success 523 >> >> null_deactivate_no_mutex 6 >> null_deactivate_no_owner 125 >> null_deactivate_owner_not_runnable 962 >> null_migrate 2131 > I think the chain-migration bits can bring down some of these > null_migrate calls substantially. > >> null_retry_same_donor 0 >> null_retry_diff_donor 2258 >> null_retry_to_idle 966 > Seems like you mostly have one task that keeps getting migrated to the > owner's CPU.、 Yes, the workload is intentionally and the waiter/holder placement can indeed make the test repeatedly migrate a task toward the owner's CPU. >> Based on your comments, I am thinking of restructuring the patch like this. >> >> First, move the final put_prev_set_next_task()/rq_set_donor() out of the >> proxy/non-proxy branches. I think the common commit target still needs to >> be the donor rather than next, because after find_proxy_task(), next may be >> the proxy owner that will actually run, while donor is still the selected >> scheduling donor/accounting context: > You are right! I had not booted into a kernel with my suggested changes > to have realized that mistake :-) ... > Your suggestions look correct to me. Perhaps you can send a v2 including > John and we can take a look. ... > Just the patches should be fine. I can crunch the performance numbers > from my side with schedstats and update on the threads. OK, I will prepare a v2 with the structure discussed here. -- Best regards, Xukai