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=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, USER_AGENT_GIT 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 9A6BEC43603 for ; Thu, 12 Dec 2019 09:25:40 +0000 (UTC) Received: from lists.ozlabs.org (lists.ozlabs.org [203.11.71.2]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 535FD21655 for ; Thu, 12 Dec 2019 09:25:40 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 535FD21655 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.vnet.ibm.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Received: from lists.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) by lists.ozlabs.org (Postfix) with ESMTP id 47YT1D2BMhzDr2F for ; Thu, 12 Dec 2019 20:25:36 +1100 (AEDT) Authentication-Results: lists.ozlabs.org; spf=none (no SPF record) smtp.mailfrom=linux.vnet.ibm.com (client-ip=148.163.158.5; helo=mx0a-001b2d01.pphosted.com; envelope-from=srikar@linux.vnet.ibm.com; receiver=) Authentication-Results: lists.ozlabs.org; dmarc=none (p=none dis=none) header.from=linux.vnet.ibm.com Received: from mx0a-001b2d01.pphosted.com (mx0b-001b2d01.pphosted.com [148.163.158.5]) (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 47YSJm35ZhzDr1Y for ; Thu, 12 Dec 2019 19:53:59 +1100 (AEDT) Received: from pps.filterd (m0098416.ppops.net [127.0.0.1]) by mx0b-001b2d01.pphosted.com (8.16.0.42/8.16.0.42) with SMTP id xBC8lneU196168 for ; Thu, 12 Dec 2019 03:53:56 -0500 Received: from e06smtp04.uk.ibm.com (e06smtp04.uk.ibm.com [195.75.94.100]) by mx0b-001b2d01.pphosted.com with ESMTP id 2wtbt33gxb-1 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=NOT) for ; Thu, 12 Dec 2019 03:53:55 -0500 Received: from localhost by e06smtp04.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Thu, 12 Dec 2019 08:53:54 -0000 Received: from b06avi18878370.portsmouth.uk.ibm.com (9.149.26.194) by e06smtp04.uk.ibm.com (192.168.101.134) with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted; (version=TLSv1/SSLv3 cipher=AES256-GCM-SHA384 bits=256/256) Thu, 12 Dec 2019 08:53:51 -0000 Received: from b06wcsmtp001.portsmouth.uk.ibm.com (b06wcsmtp001.portsmouth.uk.ibm.com [9.149.105.160]) by b06avi18878370.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id xBC8rngf44106216 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Thu, 12 Dec 2019 08:53:49 GMT Received: from b06wcsmtp001.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 5E187A4062; Thu, 12 Dec 2019 08:53:49 +0000 (GMT) Received: from b06wcsmtp001.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 8B451A405C; Thu, 12 Dec 2019 08:53:47 +0000 (GMT) Received: from srikart450.in.ibm.com (unknown [9.122.211.142]) by b06wcsmtp001.portsmouth.uk.ibm.com (Postfix) with ESMTP; Thu, 12 Dec 2019 08:53:47 +0000 (GMT) From: Srikar Dronamraju To: Michael Ellerman Subject: [PATCH v4 1/2] powerpc/vcpu: Assume dedicated processors as non-preempt Date: Thu, 12 Dec 2019 14:23:44 +0530 X-Mailer: git-send-email 2.17.1 X-TM-AS-GCONF: 00 x-cbid: 19121208-0016-0000-0000-000002D40BB9 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 19121208-0017-0000-0000-000033362E9A Message-Id: <20191212085344.17357-1-srikar@linux.vnet.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.95,18.0.572 definitions=2019-12-12_01:2019-12-12,2019-12-12 signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 lowpriorityscore=0 spamscore=0 suspectscore=0 phishscore=0 malwarescore=0 bulkscore=0 mlxlogscore=999 impostorscore=0 clxscore=1015 adultscore=0 priorityscore=1501 mlxscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-1910280000 definitions=main-1912120062 X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Juri Lelli , Parth Shah , Phil Auld , Srikar Dronamraju , "Gautham R . Shenoy" , Ihor Pasichnyk , Waiman Long , linuxppc-dev Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" With commit 247f2f6f3c70 ("sched/core: Don't schedule threads on pre-empted vCPUs"), scheduler avoids preempted vCPUs to schedule tasks on wakeup. This leads to wrong choice of CPU, which in-turn leads to larger wakeup latencies. Eventually, it leads to performance regression in latency sensitive benchmarks like soltp, schbench etc. On Powerpc, vcpu_is_preempted only looks at yield_count. If the yield_count is odd, the vCPU is assumed to be preempted. However yield_count is increased whenever LPAR enters CEDE state. So any CPU that has entered CEDE state is assumed to be preempted. Even if vCPU of dedicated LPAR is preempted/donated, it should have right of first-use since they are suppose to own the vCPU. On a Power9 System with 32 cores # lscpu Architecture: ppc64le Byte Order: Little Endian CPU(s): 128 On-line CPU(s) list: 0-127 Thread(s) per core: 8 Core(s) per socket: 1 Socket(s): 16 NUMA node(s): 2 Model: 2.2 (pvr 004e 0202) Model name: POWER9 (architected), altivec supported Hypervisor vendor: pHyp Virtualization type: para L1d cache: 32K L1i cache: 32K L2 cache: 512K L3 cache: 10240K NUMA node0 CPU(s): 0-63 NUMA node1 CPU(s): 64-127 # perf stat -a -r 5 ./schbench v5.4 v5.4 + patch Latency percentiles (usec) Latency percentiles (usec) 50.0000th: 45 50.0000th: 39 75.0000th: 62 75.0000th: 53 90.0000th: 71 90.0000th: 67 95.0000th: 77 95.0000th: 76 *99.0000th: 91 *99.0000th: 89 99.5000th: 707 99.5000th: 93 99.9000th: 6920 99.9000th: 118 min=0, max=10048 min=0, max=211 Latency percentiles (usec) Latency percentiles (usec) 50.0000th: 45 50.0000th: 34 75.0000th: 61 75.0000th: 45 90.0000th: 72 90.0000th: 53 95.0000th: 79 95.0000th: 56 *99.0000th: 691 *99.0000th: 61 99.5000th: 3972 99.5000th: 63 99.9000th: 8368 99.9000th: 78 min=0, max=16606 min=0, max=228 Latency percentiles (usec) Latency percentiles (usec) 50.0000th: 45 50.0000th: 34 75.0000th: 61 75.0000th: 45 90.0000th: 71 90.0000th: 53 95.0000th: 77 95.0000th: 57 *99.0000th: 106 *99.0000th: 63 99.5000th: 2364 99.5000th: 68 99.9000th: 7480 99.9000th: 100 min=0, max=10001 min=0, max=134 Latency percentiles (usec) Latency percentiles (usec) 50.0000th: 45 50.0000th: 34 75.0000th: 62 75.0000th: 46 90.0000th: 72 90.0000th: 53 95.0000th: 78 95.0000th: 56 *99.0000th: 93 *99.0000th: 61 99.5000th: 108 99.5000th: 64 99.9000th: 6792 99.9000th: 85 min=0, max=17681 min=0, max=121 Latency percentiles (usec) Latency percentiles (usec) 50.0000th: 46 50.0000th: 33 75.0000th: 62 75.0000th: 44 90.0000th: 73 90.0000th: 51 95.0000th: 79 95.0000th: 54 *99.0000th: 113 *99.0000th: 61 99.5000th: 2724 99.5000th: 64 99.9000th: 6184 99.9000th: 82 min=0, max=9887 min=0, max=121 Performance counter stats for 'system wide' (5 runs): context-switches 43,373 ( +- 0.40% ) 44,597 ( +- 0.55% ) cpu-migrations 1,211 ( +- 5.04% ) 220 ( +- 6.23% ) page-faults 15,983 ( +- 5.21% ) 15,360 ( +- 3.38% ) Waiman Long suggested using static_keys. Fixes: 41946c86876e ("locking/core, powerpc: Implement vcpu_is_preempted(cpu)") Cc: Parth Shah Cc: Ihor Pasichnyk Cc: Juri Lelli Cc: Phil Auld Cc: Waiman Long Cc: Gautham R. Shenoy Cc: Vaidyanathan Srinivasan Reported-by: Parth Shah Reported-by: Ihor Pasichnyk Tested-by: Juri Lelli Tested-by: Parth Shah Acked-by: Waiman Long Acked-by: Phil Auld Reviewed-by: Gautham R. Shenoy Reviewed-by: Vaidyanathan Srinivasan Signed-off-by: Srikar Dronamraju --- Changelog v1 (https://patchwork.ozlabs.org/patch/1204190/) ->v3: Code is now under CONFIG_PPC_SPLPAR as it depends on CONFIG_PPC_PSERIES. This was suggested by Waiman Long. Changelog v3 (https://patchwork.ozlabs.org/patch/1204526) ->v4: Fix a build issue in CONFIG_NUMA=n reported by Michael Ellerman by moving the relevant code from mm/numa.c to kernel/smp.c arch/powerpc/include/asm/spinlock.h | 6 ++++-- arch/powerpc/kernel/smp.c | 19 ++++++++++++++----- arch/powerpc/mm/numa.c | 8 +++----- 3 files changed, 21 insertions(+), 12 deletions(-) diff --git a/arch/powerpc/include/asm/spinlock.h b/arch/powerpc/include/asm/spinlock.h index e9a960e28f3c..f318bfe3525f 100644 --- a/arch/powerpc/include/asm/spinlock.h +++ b/arch/powerpc/include/asm/spinlock.h @@ -17,6 +17,7 @@ */ #include #ifdef CONFIG_PPC64 +#include #include #include #endif @@ -35,11 +36,12 @@ #define LOCK_TOKEN 1 #endif -#ifdef CONFIG_PPC_PSERIES +#ifdef CONFIG_PPC_SPLPAR +DECLARE_STATIC_KEY_FALSE(shared_processor); #define vcpu_is_preempted vcpu_is_preempted static inline bool vcpu_is_preempted(int cpu) { - if (!firmware_has_feature(FW_FEATURE_SPLPAR)) + if (!static_branch_unlikely(&shared_processor)) return false; return !!(be32_to_cpu(lppaca_of(cpu).yield_count) & 1); } diff --git a/arch/powerpc/kernel/smp.c b/arch/powerpc/kernel/smp.c index ea6adbf6a221..96a44157b935 100644 --- a/arch/powerpc/kernel/smp.c +++ b/arch/powerpc/kernel/smp.c @@ -1348,6 +1348,9 @@ static struct sched_domain_topology_level power9_topology[] = { { NULL, }, }; +DEFINE_STATIC_KEY_FALSE(shared_processor); +EXPORT_SYMBOL_GPL(shared_processor); + void __init smp_cpus_done(unsigned int max_cpus) { /* @@ -1359,11 +1362,17 @@ void __init smp_cpus_done(unsigned int max_cpus) if (smp_ops && smp_ops->bringup_done) smp_ops->bringup_done(); - /* - * On a shared LPAR, associativity needs to be requested. - * Hence, get numa topology before dumping cpu topology - */ - shared_proc_topology_init(); +#ifdef CONFIG_PPC_SPLPAR + if (lppaca_shared_proc(get_lppaca())) { + static_branch_enable(&shared_processor); + + /* + * On a shared LPAR, associativity needs to be requested. + * Hence, get numa topology before dumping cpu topology + */ + shared_proc_topology_init(); + } +#endif dump_numa_cpu_topology(); #ifdef CONFIG_SCHED_SMT diff --git a/arch/powerpc/mm/numa.c b/arch/powerpc/mm/numa.c index 50d68d21ddcc..c352b1dfa99e 100644 --- a/arch/powerpc/mm/numa.c +++ b/arch/powerpc/mm/numa.c @@ -1570,11 +1570,9 @@ int prrn_is_enabled(void) void __init shared_proc_topology_init(void) { - if (lppaca_shared_proc(get_lppaca())) { - bitmap_fill(cpumask_bits(&cpu_associativity_changes_mask), - nr_cpumask_bits); - numa_update_cpu_topology(false); - } + bitmap_fill(cpumask_bits(&cpu_associativity_changes_mask), + nr_cpumask_bits); + numa_update_cpu_topology(false); } static int topology_read(struct seq_file *file, void *v) -- 2.18.1