Received: by 2002:a25:b794:0:0:0:0:0 with SMTP id n20csp3035592ybh; Mon, 5 Aug 2019 10:49:52 -0700 (PDT) X-Google-Smtp-Source: APXvYqxQVvH4aG/sPqZjwRqg+j3udHlhP4k4ALlDFN0d2kKepKzhVZaKSccBUTx/mFBIf9mc3sIe X-Received: by 2002:a62:e815:: with SMTP id c21mr77029036pfi.244.1565027392689; Mon, 05 Aug 2019 10:49:52 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1565027392; cv=none; d=google.com; s=arc-20160816; b=nPg3fa1HRS5QdrAYkJ/+nCm3Q02+D47k9z9efn6KGirz570iULgU/bHhoo34UZ7SWl S6iuSg90OlSWjnkZ+S1aaU4N4nala/e7/pqMsh/5x0T/BPxjvx9JEGkNue2YWxMHRB96 pslkJc4r9OLSZarQOV2OapuTra9djqE0jQd9+t7xcBOjOd6Ve+KeF4A4SrgTFkaKLYny S1dtTLRPrfIywEy9/f3mV42U3oODJMzsIdYyrcPkmkJSwM8iQGHpFS7vNgJbY4ip8fUh UEU30C+9iU3zwRlsA61wdEKh9ID0TNFRbRwmJh/c+rHIizPWTdDAkP1bxSf+Jipf3Zf1 zCcA== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:sender:user-agent:in-reply-to :content-disposition:mime-version:references:reply-to:message-id :subject:cc:to:from:date; bh=Kfl2yXdtAkTT1klltJy6JY8uLsGsNX6QZ7ykKZJ66Hs=; b=dhh4hXM3Tkx8GA7NZtvgPPyVZgwqPvUI1dM0fImOM/uTQt5pwUyRITSPtShZaohadz EQgezSL190Lm5vM3S1MR6GJjCt/QmPzhdeJ2qov+wLq6F/G+6yt08Nqs/HQO/HXDwN6j emy05wxbASJdgW3jEWZvmjhpS/MhvwOCGMTHWzuovv+xyrpxNl/fwsBWczbcRTE4O5Ck c1V824dynDgwrmjY4Cr+vq4/piMrz8rhQvxC+fZZ4tGme42aq0B40IOcoJ701e09a4Wn 44CvE3THGEwBM5SWfX9DlnclfXVZPlsLUEfSOYqvOBUwCImdZnZSqPY6TlS3qsgaGRul vubA== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=fail (p=NONE sp=NONE dis=NONE) header.from=ibm.com Return-Path: Received: from vger.kernel.org (vger.kernel.org. [209.132.180.67]) by mx.google.com with ESMTP id t31si13162975pjb.25.2019.08.05.10.49.36; Mon, 05 Aug 2019 10:49:52 -0700 (PDT) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=fail (p=NONE sp=NONE dis=NONE) header.from=ibm.com Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728885AbfHERsn (ORCPT + 99 others); Mon, 5 Aug 2019 13:48:43 -0400 Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:22482 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726559AbfHERsm (ORCPT ); Mon, 5 Aug 2019 13:48:42 -0400 Received: from pps.filterd (m0098409.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.27/8.16.0.27) with SMTP id x75Hg1C0028554; Mon, 5 Aug 2019 13:48:00 -0400 Received: from pps.reinject (localhost [127.0.0.1]) by mx0a-001b2d01.pphosted.com with ESMTP id 2u6r1hk2dw-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Mon, 05 Aug 2019 13:48:00 -0400 Received: from m0098409.ppops.net (m0098409.ppops.net [127.0.0.1]) by pps.reinject (8.16.0.27/8.16.0.27) with SMTP id x75HgAuZ028926; Mon, 5 Aug 2019 13:47:59 -0400 Received: from ppma04dal.us.ibm.com (7a.29.35a9.ip4.static.sl-reverse.com [169.53.41.122]) by mx0a-001b2d01.pphosted.com with ESMTP id 2u6r1hk2d7-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Mon, 05 Aug 2019 13:47:59 -0400 Received: from pps.filterd (ppma04dal.us.ibm.com [127.0.0.1]) by ppma04dal.us.ibm.com (8.16.0.27/8.16.0.27) with SMTP id x75Hdn5w002303; Mon, 5 Aug 2019 17:47:58 GMT Received: from b01cxnp22036.gho.pok.ibm.com (b01cxnp22036.gho.pok.ibm.com [9.57.198.26]) by ppma04dal.us.ibm.com with ESMTP id 2u51w6jfqg-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Mon, 05 Aug 2019 17:47:58 +0000 Received: from b01ledav003.gho.pok.ibm.com (b01ledav003.gho.pok.ibm.com [9.57.199.108]) by b01cxnp22036.gho.pok.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id x75HlvrQ35062092 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Mon, 5 Aug 2019 17:47:57 GMT Received: from b01ledav003.gho.pok.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id BC378B2064; Mon, 5 Aug 2019 17:47:57 +0000 (GMT) Received: from b01ledav003.gho.pok.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id A671FB206A; Mon, 5 Aug 2019 17:47:57 +0000 (GMT) Received: from paulmck-ThinkPad-W541 (unknown [9.70.82.154]) by b01ledav003.gho.pok.ibm.com (Postfix) with ESMTP; Mon, 5 Aug 2019 17:47:57 +0000 (GMT) Received: by paulmck-ThinkPad-W541 (Postfix, from userid 1000) id F349716C9A4C; Mon, 5 Aug 2019 10:48:00 -0700 (PDT) Date: Mon, 5 Aug 2019 10:48:00 -0700 From: "Paul E. McKenney" To: Peter Zijlstra Cc: rcu@vger.kernel.org, linux-kernel@vger.kernel.org, mingo@kernel.org, jiangshanlai@gmail.com, dipankar@in.ibm.com, akpm@linux-foundation.org, mathieu.desnoyers@efficios.com, josh@joshtriplett.org, tglx@linutronix.de, rostedt@goodmis.org, dhowells@redhat.com, edumazet@google.com, fweisbec@gmail.com, oleg@redhat.com, joel@joelfernandes.org Subject: Re: [PATCH RFC tip/core/rcu 14/14] rcu/nohz: Make multi_cpu_stop() enable tick on all online CPUs Message-ID: <20190805174800.GK28441@linux.ibm.com> Reply-To: paulmck@linux.ibm.com References: <20190802151435.GA1081@linux.ibm.com> <20190802151501.13069-14-paulmck@linux.ibm.com> <20190804144317.GF2349@hirez.programming.kicks-ass.net> <20190804144835.GB2386@hirez.programming.kicks-ass.net> <20190804184159.GC28441@linux.ibm.com> <20190805080531.GH2349@hirez.programming.kicks-ass.net> <20190805145448.GI28441@linux.ibm.com> <20190805155024.GK2332@hirez.programming.kicks-ass.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190805155024.GK2332@hirez.programming.kicks-ass.net> User-Agent: Mutt/1.5.21 (2010-09-15) X-TM-AS-GCONF: 00 X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:,, definitions=2019-08-05_09:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 malwarescore=0 suspectscore=0 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1906280000 definitions=main-1908050187 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Aug 05, 2019 at 05:50:24PM +0200, Peter Zijlstra wrote: > On Mon, Aug 05, 2019 at 07:54:48AM -0700, Paul E. McKenney wrote: > > > > Right; so clearly we're not understanding what's happening. That seems > > > like a requirement for actually doing a patch. > > > > Almost but not quite. It is a requirement for a patch *that* *is* > > *supposed* *to* *be* *a* *fix*. If you are trying to prohibit me from > > writing experimental patches, please feel free to take a long walk on > > a short pier. > > > > Understood??? > > Ah, my bad, I thought you were actually proposing this as an actual > patch. I now see that is my bad, I'd overlooked the RFC part. No problem! And of course adding tracing decreases the frequency and duration of the multi_cpu_stop(). Re-running with shorter-duration triggering. ;-) Thanx, Paul