From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx0a-001b2d01.pphosted.com (mx0a-001b2d01.pphosted.com [148.163.156.1]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 41w9qz4FSNzDqnw for ; Wed, 22 Aug 2018 12:05:51 +1000 (AEST) Received: from pps.filterd (m0098393.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.22/8.16.0.22) with SMTP id w7M242s2091524 for ; Tue, 21 Aug 2018 22:05:49 -0400 Received: from e06smtp04.uk.ibm.com (e06smtp04.uk.ibm.com [195.75.94.100]) by mx0a-001b2d01.pphosted.com with ESMTP id 2m0x41s567-1 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=NOT) for ; Tue, 21 Aug 2018 22:05:49 -0400 Received: from localhost by e06smtp04.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Wed, 22 Aug 2018 03:05:47 +0100 Date: Tue, 21 Aug 2018 19:05:42 -0700 From: Srikar Dronamraju To: Michael Ellerman Cc: linuxppc-dev , Michal Suchanek , Manjunatha H R , Michael Bringmann Subject: Re: [v5] powerpc/topology: Get topology for shared processors at boot Reply-To: Srikar Dronamraju References: <1534517679-10792-1-git-send-email-srikar@linux.vnet.ibm.com> <41vnBN2hf3z9s8T@ozlabs.org> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 In-Reply-To: <41vnBN2hf3z9s8T@ozlabs.org> Message-Id: <20180822020542.GC2080@linux.vnet.ibm.com> List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , * Michael Ellerman [2018-08-21 20:35:23]: > On Fri, 2018-08-17 at 14:54:39 UTC, Srikar Dronamraju wrote: > > On a shared lpar, Phyp will not update the cpu associativity at boot > > time. Just after the boot system does recognize itself as a shared lpar and > > trigger a request for correct cpu associativity. But by then the scheduler > > would have already created/destroyed its sched domains. > > > > This causes > > - Broken load balance across Nodes causing islands of cores. > > - Performance degradation esp if the system is lightly loaded > > - dmesg to wrongly report all cpus to be in Node 0. > > - Messages in dmesg saying borken topology. > > - With commit 051f3ca02e46 ("sched/topology: Introduce NUMA identity > > node sched domain"), can cause rcu stalls at boot up. > > > > > > Previous attempt to solve this problem > > https://patchwork.ozlabs.org/patch/530090/ > > > > Reported-by: Manjunatha H R > > Signed-off-by: Srikar Dronamraju > > Applied to powerpc next, thanks. > > https://git.kernel.org/powerpc/c/2ea62630681027c455117aa471ea3a > Once it gets to Linus's tree, can we request this to be included in stable trees? -- Thanks and Regards Srikar Dronamraju