From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757321AbdJKI4h (ORCPT ); Wed, 11 Oct 2017 04:56:37 -0400 Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:57374 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1756774AbdJKI4e (ORCPT ); Wed, 11 Oct 2017 04:56:34 -0400 Subject: Re: [PATCH] powerpc/powernv: Add kernel cmdline parameter to disable imc To: Stewart Smith , Michael Ellerman Cc: linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org, maddy@linux.vnet.ibm.com, hemant@linux.vnet.ibm.com References: <1507531597-25947-1-git-send-email-anju@linux.vnet.ibm.com> <87wp43wf2v.fsf@concordia.ellerman.id.au> <87infmeonf.fsf@linux.vnet.ibm.com> From: Anju T Sudhakar Date: Wed, 11 Oct 2017 14:26:27 +0530 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.3.0 MIME-Version: 1.0 In-Reply-To: <87infmeonf.fsf@linux.vnet.ibm.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Content-Language: en-US X-TM-AS-GCONF: 00 x-cbid: 17101108-0048-0000-0000-000001F3ECEE X-IBM-SpamModules-Scores: X-IBM-SpamModules-Versions: BY=3.00007877; HX=3.00000241; KW=3.00000007; PH=3.00000004; SC=3.00000235; SDB=6.00929508; UDB=6.00467832; IPR=6.00709779; BA=6.00005633; NDR=6.00000001; ZLA=6.00000005; ZF=6.00000009; ZB=6.00000000; ZP=6.00000000; ZH=6.00000000; ZU=6.00000002; MB=3.00017488; XFM=3.00000015; UTC=2017-10-11 08:56:32 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 17101108-0049-0000-0000-000042D5509F Message-Id: <06fe39eb-d5fe-4472-56b4-f66390d7fad9@linux.vnet.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:,, definitions=2017-10-11_02:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 spamscore=0 suspectscore=0 malwarescore=0 phishscore=0 adultscore=0 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1707230000 definitions=main-1710110127 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi mpe, stewart, On Wednesday 11 October 2017 01:55 AM, Stewart Smith wrote: > Michael Ellerman writes: >> Anju T Sudhakar writes: >> >>> Add a kernel command line parameter option to disable In-Memory Collection >>> (IMC) counters and add documentation. This helps in debug. >> I'd really rather we didn't. Do we *really* need this? >> >> We don't have command line parameters to disable any of the other ~20 >> PMUs, why is this one special? This one is really helpful in debugging, incase if we want to proceed without nest counters  OR core counters . But if we have the facility to do the same from petitboot, its fine. > You could also do the same thing by editing the device tree before > booting your kernel, we do have the facility to do that in petitboot. > > A recent firmware patch: https://patchwork.ozlabs.org/patch/823249/ > would fix the firmware implementation where the counters were already > running before the INIT/START calls, which are likely the cause of the > problems that this patch is trying to work around. > > I propose we have the firmware do the right thing and nothing special in > kernel. i.e. not to merge this. > Agreed. Thanks, Anju