From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from casper.infradead.org (casper.infradead.org [90.155.50.34]) (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 39C5A148850 for ; Tue, 10 Feb 2026 18:35:25 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=90.155.50.34 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1770748527; cv=none; b=A5StDXnh3ngkrZpGhvF+pd+qmybVRsmGE5tp0zCL8bvCbSExF15BwGvbBHxctzC9x73P+tSRVevqnwFp/4UND2lQZusITEGUatWI4v4EYLKz7qqdPKHbNbqav/drEP0YD+/IR7DA4UXUzHfuIIDNXik4y09Gxt31f/L+XFcGA3s= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1770748527; c=relaxed/simple; bh=Y9xPfTDW9MGkGv7nNt3j4hKvbxN9LOcHjzTdtp2TMKc=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=kAs1zoI8WgBtUpauML5/BhmiFkPB/RlyOj5icsMuDJeaoa6g9r9Srwjq8HR+xMNFpJSMjapzsTLOzdVFSjdVSyL+H2F4szwYIT1x7HB/8dhlWi9g5wZPwnb4S8LoSwYsEgA2yFrJdPKBWBa90wTtg4tCVeuJgnp9lXr2fNBkrnk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=infradead.org; spf=none smtp.mailfrom=infradead.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b=a8GpgdIs; arc=none smtp.client-ip=90.155.50.34 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=infradead.org Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=infradead.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="a8GpgdIs" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=Y9xPfTDW9MGkGv7nNt3j4hKvbxN9LOcHjzTdtp2TMKc=; b=a8GpgdIstOjntdXAefO9PDZhml Z8k25W9Ku0i4Mnj8VZkFzdYAOv2h5o0DxLvLAwS6y0cyXNJH0IGSx1VjOZOPMtqBw0hqyiYEg8iE+ ytwrxKKDlU0eYwwhdfTy+fbfjpquZK4u05dJtS+9UBb3OMndeszLkhC+Fs1vSEaYkJU3uQAHQ3EH7 r6KdfR1ID9thoQLprYQU4P35UrDl7uX9i8H/Qv57XsZMAfPx4Vizj7CKXuWLYKTf6jdeJ9Q0OZQel lvsaXJfAcab++4DaBYuTYcTVKaMgNKOF5gGvl56XhWTxWEWoZCE7ztRO7tynHgUD1MzE/Nr+LC1QO d01K7eTQ==; Received: from 77-249-17-252.cable.dynamic.v4.ziggo.nl ([77.249.17.252] helo=noisy.programming.kicks-ass.net) by casper.infradead.org with esmtpsa (Exim 4.98.2 #2 (Red Hat Linux)) id 1vpsZw-0000000BTix-0RCR; Tue, 10 Feb 2026 18:35:16 +0000 Received: by noisy.programming.kicks-ass.net (Postfix, from userid 1000) id 9AF45300754; Tue, 10 Feb 2026 19:35:15 +0100 (CET) Date: Tue, 10 Feb 2026 19:35:15 +0100 From: Peter Zijlstra To: K Prateek Nayak Cc: Doug Smythies , mingo@kernel.org, juri.lelli@redhat.com, vincent.guittot@linaro.org, dietmar.eggemann@arm.com, rostedt@goodmis.org, bsegall@google.com, mgorman@suse.de, vschneid@redhat.com, linux-kernel@vger.kernel.org, wangtao554@huawei.com, quzicheng@huawei.com, wuyun.abel@bytedance.com Subject: Re: [PATCH 0/4] sched: Various reweight_entity() fixes Message-ID: <20260210183515.GI3016024@noisy.programming.kicks-ass.net> References: <20260130093439.803225718@infradead.org> <4c48fe59-8ff3-41fb-83cb-869409f6fbc6@amd.com> <20260203111134.GL1282955@noisy.programming.kicks-ass.net> <38ef3462-4c4e-4f40-8d63-84dd71cbd043@amd.com> <20260209154718.GW1282955@noisy.programming.kicks-ass.net> <001901dc9aa3$cbad47f0$6307d7d0$@telus.net> <04ffa7ce-85ba-431b-91ab-f725f31b03ed@amd.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <04ffa7ce-85ba-431b-91ab-f725f31b03ed@amd.com> On Tue, Feb 10, 2026 at 11:39:14PM +0530, K Prateek Nayak wrote: > Since you mentioned there is some bound to the number of copies when > the hang is observed, can you please share your system details and > the number of CPUs it has? He had that information in another email, 6 cores/12 threads. For me, I got to 21160 spread over 12 threads when it went boom. That translates to aroun 1763 per CPU. Which is a fairly silly number of active tasks, but it *should* work. It's a bit tedious to reproduce, but I'll prod at it some too.