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 X-Spam-Level: X-Spam-Status: No, score=-5.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 05575C64E7A for ; Wed, 18 Nov 2020 14:44:57 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8BB48221FB for ; Wed, 18 Nov 2020 14:44:56 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="g7lMBbv9" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727053AbgKROou (ORCPT ); Wed, 18 Nov 2020 09:44:50 -0500 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:24627 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726306AbgKROot (ORCPT ); Wed, 18 Nov 2020 09:44:49 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1605710688; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=YmxyhTdWNlkE/cIxG1YVUOv6A3OxAK7WsSp8uPLWUVg=; b=g7lMBbv9CS9GVBQ0FEkHhWLc1TRN2sw8twGW8ZvjsjTmzBTN9q6LlzpcdwhN+VxEQNfYZS dlSOOf88s5kNwot2Y0oyY8pRSoTOngC5o6pzzH3eLuTsdNDmtUZ5Cya1K4EotJvhwdgrSk a/Cen1zSX9Qly4wdAGb8YW4WwxomVyA= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-337-uukPLlPLObe4B95_nFsnug-1; Wed, 18 Nov 2020 09:44:46 -0500 X-MC-Unique: uukPLlPLObe4B95_nFsnug-1 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.phx2.redhat.com [10.5.11.16]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 0BC3610051BC; Wed, 18 Nov 2020 14:44:44 +0000 (UTC) Received: from ovpn-66-242.rdu2.redhat.com (ovpn-66-242.rdu2.redhat.com [10.10.66.242]) by smtp.corp.redhat.com (Postfix) with ESMTP id 7A6845C1A3; Wed, 18 Nov 2020 14:44:35 +0000 (UTC) Message-ID: Subject: Re: [PATCH v4 11/19] sched/core: Make migrate disable and CPU hotplug cooperative From: Qian Cai To: Valentin Schneider Cc: Peter Zijlstra , tglx@linutronix.de, mingo@kernel.org, linux-kernel@vger.kernel.org, bigeasy@linutronix.de, qais.yousef@arm.com, swood@redhat.com, juri.lelli@redhat.com, vincent.guittot@linaro.org, dietmar.eggemann@arm.com, rostedt@goodmis.org, bsegall@google.com, mgorman@suse.de, bristot@redhat.com, vincent.donnefort@arm.com, tj@kernel.org, ouwen210@hotmail.com Date: Wed, 18 Nov 2020 09:44:34 -0500 In-Reply-To: References: <20201023101158.088940906@infradead.org> <20201023102347.067278757@infradead.org> Content-Type: text/plain; charset="UTF-8" Mime-Version: 1.0 Content-Transfer-Encoding: 7bit X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 2020-11-17 at 19:28 +0000, Valentin Schneider wrote: > We did have some breakage in that area, but all the holes I was aware of > have been plugged. What would help here is to see which tasks are still > queued on that outgoing CPU, and their recent activity. > > Something like > - ftrace_dump_on_oops on your kernel cmdline > - trace-cmd start -e 'sched:*' > > > ought to do it. Then you can paste the (tail of the) ftrace dump. > > I also had this laying around, which may or may not be of some help: Once I have found a reliable reproducer, I'll report back.