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=-9.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS autolearn=ham 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 20A5DC433E1 for ; Wed, 26 Aug 2020 09:40:36 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id F09042071E for ; Wed, 26 Aug 2020 09:40:35 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=ibm.com header.i=@ibm.com header.b="li3s+Cpx" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728578AbgHZJke (ORCPT ); Wed, 26 Aug 2020 05:40:34 -0400 Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:14080 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727884AbgHZJk1 (ORCPT ); Wed, 26 Aug 2020 05:40:27 -0400 Received: from pps.filterd (m0098404.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.42/8.16.0.42) with SMTP id 07Q9XOaD059228; Wed, 26 Aug 2020 05:40:18 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ibm.com; h=date : from : to : cc : subject : message-id : reply-to : references : mime-version : content-type : in-reply-to; s=pp1; bh=N7+aa+XxNWIP45367pCc49nejHJb7V3eQKgrc57njM8=; b=li3s+CpxcaYPFTQiUOSd8O/26MuRYsCODFBOiXge6osQelC0cLYmzWrkj7s2KJUkHKmY DY0ghXLXL9zT4tBi0Fjqjif5QYVGA55C7V5trHrAEkW/yYf/DK5/ysHlSfehQprHPuZw 1S7abgmYRGeYiHNbxT05fCVs2ct0hL47yOdNIQrE+N7K+z/ws3bcXDWmYYd1DJ4OpWAC kTwZbEotA3v0IhD4ZR867ZLirc4Zpq1nFXkPsMcHXiXeZOsjCDbcPx0xxevnbPJi7MAV RR88NjPFVKCvKFzHGbelWSIyPbsRgxdptkTSd93scGg1xDOIfKI9c+9Msy6PiqXtx6vw wg== Received: from pps.reinject (localhost [127.0.0.1]) by mx0a-001b2d01.pphosted.com with ESMTP id 335m1w2dhc-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Wed, 26 Aug 2020 05:40:18 -0400 Received: from m0098404.ppops.net (m0098404.ppops.net [127.0.0.1]) by pps.reinject (8.16.0.36/8.16.0.36) with SMTP id 07Q9Y2J7062048; Wed, 26 Aug 2020 05:40:18 -0400 Received: from ppma05fra.de.ibm.com (6c.4a.5195.ip4.static.sl-reverse.com [149.81.74.108]) by mx0a-001b2d01.pphosted.com with ESMTP id 335m1w2dfc-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Wed, 26 Aug 2020 05:40:17 -0400 Received: from pps.filterd (ppma05fra.de.ibm.com [127.0.0.1]) by ppma05fra.de.ibm.com (8.16.0.42/8.16.0.42) with SMTP id 07Q9c0Lr005769; Wed, 26 Aug 2020 09:40:15 GMT Received: from b06avi18626390.portsmouth.uk.ibm.com (b06avi18626390.portsmouth.uk.ibm.com [9.149.26.192]) by ppma05fra.de.ibm.com with ESMTP id 335j2704ed-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Wed, 26 Aug 2020 09:40:15 +0000 Received: from d06av21.portsmouth.uk.ibm.com (d06av21.portsmouth.uk.ibm.com [9.149.105.232]) by b06avi18626390.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 07Q9cgVD66126184 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 26 Aug 2020 09:38:42 GMT Received: from d06av21.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id BF8A95204F; Wed, 26 Aug 2020 09:40:12 +0000 (GMT) Received: from drishya.in.ibm.com (unknown [9.199.54.64]) by d06av21.portsmouth.uk.ibm.com (Postfix) with ESMTPS id 55DA052054; Wed, 26 Aug 2020 09:40:11 +0000 (GMT) Date: Wed, 26 Aug 2020 15:10:09 +0530 From: Vaidyanathan Srinivasan To: Pratik Rajesh Sampat Cc: linuxppc-dev@lists.ozlabs.org, mpe@ellerman.id.au, npiggin@gmail.com, mikey@neuling.org, ego@linux.vnet.ibm.com, linux-kernel@vger.kernel.org, pratik.r.sampat@gmail.com Subject: Re: [PATCH] Revert "powerpc/powernv/idle: Replace CPU feature check with PVR check" Message-ID: <20200826094009.GC48285@drishya.in.ibm.com> Reply-To: svaidy@linux.ibm.com References: <20200826082918.89306-1-psampat@linux.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline In-Reply-To: <20200826082918.89306-1-psampat@linux.ibm.com> X-TM-AS-GCONF: 00 X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.235,18.0.687 definitions=2020-08-26_06:2020-08-25,2020-08-26 signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 phishscore=0 spamscore=0 impostorscore=0 mlxscore=0 lowpriorityscore=0 priorityscore=1501 adultscore=0 bulkscore=0 clxscore=1011 suspectscore=0 malwarescore=0 mlxlogscore=999 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2006250000 definitions=main-2008260075 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org * Pratik Rajesh Sampat [2020-08-26 13:59:18]: > Cpuidle stop state implementation has minor optimizations for P10 > where hardware preserves more SPR registers compared to P9. > The current P9 driver works for P10, although does few extra > save-restores. P9 driver can provide the required power management > features like SMT thread folding and core level power savings > on a P10 platform. > > Until the P10 stop driver is available, revert the commit which > allows for only P9 systems to utilize cpuidle and blocks all > idle stop states for P10. > Cpu idle states are enabled and tested on the P10 platform > with this fix. > > This reverts commit 8747bf36f312356f8a295a0c39ff092d65ce75ae. > > Fixes: 8747bf36f312 ("powerpc/powernv/idle: Replace CPU feature check with PVR check") > Signed-off-by: Pratik Rajesh Sampat Reviewed-by: Vaidyanathan Srinivasan > --- > @mpe: This revert would resolve a staging issue wherein the P10 stop > driver is not yet ready while cpuidle stop states need not be blocked > on 5.9 for Power10 systems which could cause SMT folding related > performance issues. > > The P10 stop driver is in the works here: > https://lists.ozlabs.org/pipermail/linuxppc-dev/2020-August/216773.html > > arch/powerpc/platforms/powernv/idle.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/arch/powerpc/platforms/powernv/idle.c b/arch/powerpc/platforms/powernv/idle.c > index 77513a80cef9..345ab062b21a 100644 > --- a/arch/powerpc/platforms/powernv/idle.c > +++ b/arch/powerpc/platforms/powernv/idle.c > @@ -1223,7 +1223,7 @@ static void __init pnv_probe_idle_states(void) > return; > } > > - if (pvr_version_is(PVR_POWER9)) > + if (cpu_has_feature(CPU_FTR_ARCH_300)) > pnv_power9_idle_init(); > > for (i = 0; i < nr_pnv_idle_states; i++) This revert solves the stated problem and makes kernel v5.9 work reasonable well on P10 with stop states which are required for SMT mode changes. Complete P10 driver has been in the works and will build on this fix and complete the required platform support and optimizations. --Vaidy