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 3yBnsK2nWTzDr5S for ; Wed, 11 Oct 2017 19:56:37 +1100 (AEDT) Received: from pps.filterd (m0098393.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.21/8.16.0.21) with SMTP id v9B8u4F1119382 for ; Wed, 11 Oct 2017 04:56:35 -0400 Received: from e12.ny.us.ibm.com (e12.ny.us.ibm.com [129.33.205.202]) by mx0a-001b2d01.pphosted.com with ESMTP id 2dhb71cafu-1 (version=TLSv1.2 cipher=AES256-SHA bits=256 verify=NOT) for ; Wed, 11 Oct 2017 04:56:34 -0400 Received: from localhost by e12.ny.us.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Wed, 11 Oct 2017 04:56:33 -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 MIME-Version: 1.0 In-Reply-To: <87infmeonf.fsf@linux.vnet.ibm.com> Content-Type: text/plain; charset=utf-8; format=flowed Message-Id: <06fe39eb-d5fe-4472-56b4-f66390d7fad9@linux.vnet.ibm.com> List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , 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