From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 933D7C982DA for ; Sat, 19 Sep 2026 10:57:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Transfer-Encoding: Content-Type:In-Reply-To:From:References:Cc:To:Subject:MIME-Version:Date: Message-ID:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=0Azc/C3HhF90ci37ecBaOzx+YdXBirsxcxvj2DFleSo=; b=leqJiKB63jcAlIUKcsXxucoYGD pLfE4bnFvRJqbU2VSG9GIjpE1WdYdVdJZhDzWn23qKw3o5F484eyb0R9SYUp5TDZ1QyUe0gDONg4t JQc+oA0b0CS2LF1AeBCOkETac4SmAYMSl5ONXp6p0v2ZEeW5HQRbc5ETqyQEVBaHFkX8oI3aO8dQp yCdX5gZpq8XExrGJzNZsMRxS8NQd3j/cY8+MxRZySihQk35Nv7FrCIJOJSdZnL9JKv7Yrt4z3qwOS omYOhT7XisdSwu7DMKXT5861uI6zw3+8FEuf10WmDtLBpKRPV0j6YAUDvJJO+7sfCfCTYg9ipktri oAc7kifg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.99.1 #2 (Red Hat Linux)) id 1x7slG-0000000GCT9-0KQU; Sat, 19 Sep 2026 10:57:38 +0000 Received: from mail-m20521016483.xmail.ntesmail.com ([205.210.164.83]) by bombadil.infradead.org with esmtps (Exim 4.99.1 #2 (Red Hat Linux)) id 1x7slB-0000000GCSj-3BsR for linux-arm-kernel@lists.infradead.org; Sat, 19 Sep 2026 10:57:36 +0000 Received: from [172.16.12.90] (unknown [61.154.14.86]) by smtp.qiye.163.com (Hmail) with ESMTP id 4e5ef389a; Sat, 19 Sep 2026 18:57:28 +0800 (GMT+08:00) Message-ID: <7e456d83-96b2-443b-ae51-af64e7e8a150@rock-chips.com> Date: Sat, 19 Sep 2026 18:57:08 +0800 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [BUG?] Possible scheduler bug on Rock 5B RK3588 on 7.2.5 To: No SPAM here Cc: Peter Zijlstra , linux-arm-kernel@lists.infradead.org References: <11cdc24a-962a-4f44-b91c-445c2ac80c02@rock-chips.com> Content-Language: en-US From: Chaoyi Chen In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-HM-Tid: 0aa0b95061f003a7kunme8f5713bfdd417 X-HM-MType: 1 X-HM-Spam-Status: e1kfGhgUHx5ZQUpXWQgPGg8OCBgUHx5ZQUlOS1dZFg8aDwILHllBWSg2Ly tZV1koWUFITzdXWRgWCB1ZQUpXWS1ZQUlXWQ8JGhUIEh9ZQVkaSB1MVktDQkJNHRhJS0pOQ1YVFA kWGhdVEwETFhoSFyQUDg9ZV1kYEgtZQVlNSlVKTk9VSk9VQ01ZV1kWGg8SFR0UWUFZT0tIVUJCSU 5LVUpLS1VKQktCWQY+ DKIM-Signature: a=rsa-sha256; b=iVBQqsbBaFOj0oSc1oW9Xoq8zTcSQidnNeY2MRYM3p0x2W43yDkd1KA71xQF5qy35h0bSU7JWliWpgnTkRmpnvdqscf4EGsC0rlf387TNb7c6/rcp5jBtU+Lh15cx90+dajnRbT3JroBG7MHzBsLvID8trA606mDITWe34ozJgo=; c=relaxed/relaxed; s=default; d=rock-chips.com; v=1; bh=0Azc/C3HhF90ci37ecBaOzx+YdXBirsxcxvj2DFleSo=; h=date:mime-version:subject:message-id:from; X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.9.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260919_035734_619477_568A8614 X-CRM114-Status: GOOD ( 15.64 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On 9/19/2026 12:11 AM, No SPAM here wrote: > I have now retested with kernel 7.3.0-rc3 and this bug appears to have been fixed. The same command now runs all 8 cores at 100% for the duration of the test and the resulting numbers differ (in favour of the 6.18.52 CLUSTER=n kernel) by a maximum of 0.25% which is measurement error. > Thanks! Looks like this series fixes the problem: https://lore.kernel.org/all/20260720-rneri-fix-cas-clusters-v6-0-bb500bf4afd4@linux.intel.com/ > Thanks for your attention. This can be marked as solved. > > Trevor > > > Sent with Proton Mail secure email. > > On Friday, 18 September 2026 at 02:22, Chaoyi Chen wrote: > >> On 9/18/2026 3:15 AM, No SPAM here wrote: >>> Hi >>> >>> On Thursday, 17 September 2026 at 03:37, Chaoyi Chen wrote: >>> >>>> Hello Trevor, >>>> >>>> On 9/17/2026 9:21 AM, No SPAM here wrote: >>>>>> Would you mind trying to disable `CONFIG_SCHED_CLUSTER` and checking whether >>>>>> the problem still reproduces? >>> >>> trevor@rock-5b:~$ uname -a >>> Linux rock-5b 6.18.52-current-rockchip64 #1 SMP PREEMPT Mon Sep 14 11:36:19 UTC 2026 aarch64 GNU/Linux >>> trevor@rock-5b:~$ grep CONFIG_SCHED_CLU /boot/config-6.18.52-current-rockchip64 >>> # CONFIG_SCHED_CLUSTER is not set >>> trevor@rock-5b:~$ sar | tail -5 >>> >>> 18:50:15 CPU %user %nice %system %iowait %steal %idle >>> 19:00:15 all 99.89 0.00 0.11 0.00 0.00 0.00 >>> 19:10:15 all 99.89 0.00 0.11 0.00 0.00 0.00 >>> Average: all 99.89 0.00 0.11 0.00 0.00 0.00 >>> >>> Been running stress --cpu 8 since 18:47 and so far it is using all 8 cores at 100%. It would normally have shown the 7/8ths problem after 20s or so, maybe 2 or 3 minutes at max. So I'd say this setting is definitely involved. >>> >> >> Thank you very much for testing. I'm not a scheduler expert, but I see >> that CONFIG_SCHED_CLUSTER is enabled by default on arm64 [0]. >> >> Peter is the maintainer and author of this series. >> @Peter, do you have any further insights? Thank you! >> >> This thread background is here[1]. >> >> [0]: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=7bd291abe2da09f59dca81f35a4ec220e5e138a2 >> [1]: https://lore.kernel.org/all/f15f8166-c1e4-45dc-9ddd-4ec887e415eb@gdead.co.uk/ >> >> -- >> Best, >> Chaoyi >> > -- Best, Chaoyi