From patchwork Wed Jul 29 06:47:31 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Gautham R Shenoy X-Patchwork-Id: 11690419 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 71D65913 for ; Wed, 29 Jul 2020 06:48:04 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 5EA062084D for ; Wed, 29 Jul 2020 06:48:04 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727054AbgG2Gr5 (ORCPT ); Wed, 29 Jul 2020 02:47:57 -0400 Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:49014 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726445AbgG2Grv (ORCPT ); Wed, 29 Jul 2020 02:47:51 -0400 Received: from pps.filterd (m0098393.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.42/8.16.0.42) with SMTP id 06T64WLj117379; Wed, 29 Jul 2020 02:47:47 -0400 Received: from pps.reinject (localhost [127.0.0.1]) by mx0a-001b2d01.pphosted.com with ESMTP id 32jw71196q-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Wed, 29 Jul 2020 02:47:47 -0400 Received: from m0098393.ppops.net (m0098393.ppops.net [127.0.0.1]) by pps.reinject (8.16.0.36/8.16.0.36) with SMTP id 06T6511m119473; Wed, 29 Jul 2020 02:47:46 -0400 Received: from ppma05wdc.us.ibm.com (1b.90.2fa9.ip4.static.sl-reverse.com [169.47.144.27]) by mx0a-001b2d01.pphosted.com with ESMTP id 32jw711967-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Wed, 29 Jul 2020 02:47:46 -0400 Received: from pps.filterd (ppma05wdc.us.ibm.com [127.0.0.1]) by ppma05wdc.us.ibm.com (8.16.0.42/8.16.0.42) with SMTP id 06T6TjHF010667; Wed, 29 Jul 2020 06:47:45 GMT Received: from b01cxnp22034.gho.pok.ibm.com (b01cxnp22034.gho.pok.ibm.com [9.57.198.24]) by ppma05wdc.us.ibm.com with ESMTP id 32gcy9qkku-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Wed, 29 Jul 2020 06:47:45 +0000 Received: from b01ledav006.gho.pok.ibm.com (b01ledav006.gho.pok.ibm.com [9.57.199.111]) by b01cxnp22034.gho.pok.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 06T6ljUp55247354 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 29 Jul 2020 06:47:45 GMT Received: from b01ledav006.gho.pok.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id EF943AC05B; Wed, 29 Jul 2020 06:47:44 +0000 (GMT) Received: from b01ledav006.gho.pok.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 2474DAC059; Wed, 29 Jul 2020 06:47:44 +0000 (GMT) Received: from sofia.ibm.com (unknown [9.85.85.173]) by b01ledav006.gho.pok.ibm.com (Postfix) with ESMTP; Wed, 29 Jul 2020 06:47:44 +0000 (GMT) Received: by sofia.ibm.com (Postfix, from userid 1000) id 99BD22E2FF3; Wed, 29 Jul 2020 12:17:39 +0530 (IST) From: "Gautham R. Shenoy" To: Nicholas Piggin , Anton Blanchard , Nathan Lynch , Michael Ellerman , Michael Neuling , Vaidyanathan Srinivasan Cc: linuxppc-dev@ozlabs.org, linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org, "Gautham R. Shenoy" Subject: [PATCH v2 0/3] cpuidle-pseries: Parse extended CEDE information for idle. Date: Wed, 29 Jul 2020 12:17:31 +0530 Message-Id: <1596005254-25753-1-git-send-email-ego@linux.vnet.ibm.com> X-Mailer: git-send-email 1.8.3.1 X-TM-AS-GCONF: 00 X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.235,18.0.687 definitions=2020-07-29_02:2020-07-28,2020-07-29 signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 clxscore=1015 bulkscore=0 spamscore=0 impostorscore=0 adultscore=0 suspectscore=0 lowpriorityscore=0 malwarescore=0 phishscore=0 mlxscore=0 mlxlogscore=999 priorityscore=1501 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2006250000 definitions=main-2007290041 Sender: linux-pm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pm@vger.kernel.org From: "Gautham R. Shenoy" Hi, This is a v2 of the patch series to parse the extended CEDE information in the pseries-cpuidle driver. The v1 of this patchset can be found here : https://lore.kernel.org/linuxppc-dev/1594120299-31389-1-git-send-email-ego@linux.vnet.ibm.com/ The change from v1 --> v2 : * Dropped Patches 4 and 5 which would expose extended idle-states, that wakeup on external interrupts, to cpuidle framework. These were RFC patches in v1. Dropped them because currently the only extended CEDE state that wakesup on external interrupts is CEDE(1) which adds no signifcant value over CEDE(0). * Rebased the patches onto powerpc/merge. * No changes in code for Patches 1-3. Motivation: =========== On pseries Dedicated Linux LPARs, apart from the polling snooze idle state, we currently have the CEDE idle state which cedes the CPU to the hypervisor with latency-hint = 0. However, the PowerVM hypervisor supports additional extended CEDE states, which can be queried through the "ibm,get-systems-parameter" rtas-call with the CEDE_LATENCY_TOKEN. The hypervisor maps these extended CEDE states to appropriate platform idle-states in order to provide energy-savings as well as shifting power to the active units. On existing pseries LPARs today we have extended CEDE with latency-hints {1,2} supported. The patches in this patchset, adds code to parse the CEDE latency records provided by the hypervisor. We use this information to determine the wakeup latency of the regular CEDE (which we have been so far hardcoding to 10us while experimentally it is much lesser ~ 1us), by looking at the wakeup latency provided by the hypervisor for Extended CEDE states. Since the platform currently advertises Extended CEDE 1 to have wakeup latency of 2us, we can be sure that the wakeup latency of the regular CEDE is no more than this. With Patches 1-3, we see an improvement in the single-threaded performance on ebizzy. 2 ebizzy threads bound to the same big-core. 25% improvement in the avg records/s (higher the better) with patches 1-3. x without_patches * with_patches N Min Max Median Avg Stddev x 10 2491089 5834307 5398375 4244335 1596244.9 * 10 2893813 5834474 5832448 5327281.3 1055941.4 We do not observe any major regression in either the context_switch2 benchmark or the schbench benchmark context_switch2 across CPU0 CPU1 (Both belong to same big-core, but different small cores). We observe a minor 0.14% regression in the number of context-switches (higher is better). x without_patch * with_patch N Min Max Median Avg Stddev x 500 348872 362236 354712 354745.69 2711.827 * 500 349422 361452 353942 354215.4 2576.9258 context_switch2 across CPU0 CPU8 (Different big-cores). We observe a 0.37% improvement in the number of context-switches (higher is better). x without_patch * with_patch N Min Max Median Avg Stddev x 500 287956 294940 288896 288977.23 646.59295 * 500 288300 294646 289582 290064.76 1161.9992 schbench: No major difference could be seen until the 99.9th percentile. Without-patch Latency percentiles (usec) 50.0th: 29 75.0th: 39 90.0th: 49 95.0th: 59 *99.0th: 13104 99.5th: 14672 99.9th: 15824 min=0, max=17993 With-patch: Latency percentiles (usec) 50.0th: 29 75.0th: 40 90.0th: 50 95.0th: 61 *99.0th: 13648 99.5th: 14768 99.9th: 15664 min=0, max=29812 Gautham R. Shenoy (3): cpuidle-pseries: Set the latency-hint before entering CEDE cpuidle-pseries: Add function to parse extended CEDE records cpuidle-pseries : Fixup exit latency for CEDE(0) drivers/cpuidle/cpuidle-pseries.c | 167 +++++++++++++++++++++++++++++++++++++- 1 file changed, 165 insertions(+), 2 deletions(-)