From patchwork Mon Apr 22 06:32:31 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Abhishek Goel X-Patchwork-Id: 10910713 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id DD4961515 for ; Mon, 22 Apr 2019 06:34:36 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id CE125284D2 for ; Mon, 22 Apr 2019 06:34:36 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id BDE352852D; Mon, 22 Apr 2019 06:34:36 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 99531284D2 for ; Mon, 22 Apr 2019 06:34:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726211AbfDVGee (ORCPT ); Mon, 22 Apr 2019 02:34:34 -0400 Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:44294 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726190AbfDVGee (ORCPT ); Mon, 22 Apr 2019 02:34:34 -0400 Received: from pps.filterd (m0098413.ppops.net [127.0.0.1]) by mx0b-001b2d01.pphosted.com (8.16.0.27/8.16.0.27) with SMTP id x3M6XkvF074983 for ; Mon, 22 Apr 2019 02:34:33 -0400 Received: from e06smtp02.uk.ibm.com (e06smtp02.uk.ibm.com [195.75.94.98]) by mx0b-001b2d01.pphosted.com with ESMTP id 2s1351rhjt-1 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=NOT) for ; Mon, 22 Apr 2019 02:34:33 -0400 Received: from localhost by e06smtp02.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! 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Violators will be prosecuted; (version=TLSv1/SSLv3 cipher=AES256-GCM-SHA384 bits=256/256) Mon, 22 Apr 2019 07:34:28 +0100 Received: from d06av21.portsmouth.uk.ibm.com (d06av21.portsmouth.uk.ibm.com [9.149.105.232]) by b06cxnps3074.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id x3M6YR3c55312534 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Mon, 22 Apr 2019 06:34:27 GMT Received: from d06av21.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id C512152057; Mon, 22 Apr 2019 06:34:27 +0000 (GMT) Received: from boston16h.aus.stglabs.ibm.com (unknown [9.3.23.78]) by d06av21.portsmouth.uk.ibm.com (Postfix) with ESMTP id 6864352051; Mon, 22 Apr 2019 06:34:26 +0000 (GMT) From: Abhishek Goel To: linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-pm@vger.kernel.org Cc: rjw@rjwysocki.net, daniel.lezcano@linaro.org, mpe@ellerman.id.au, ego@linux.vnet.ibm.com, dja@axtens.net, Abhishek Goel Subject: [PATCH 1/1] cpuidle-powernv : forced wakeup for stop lite states Date: Mon, 22 Apr 2019 01:32:31 -0500 X-Mailer: git-send-email 2.17.1 In-Reply-To: <20190422063231.51043-1-huntbag@linux.vnet.ibm.com> References: <20190422063231.51043-1-huntbag@linux.vnet.ibm.com> X-TM-AS-GCONF: 00 x-cbid: 19042206-0008-0000-0000-000002DC3A44 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 19042206-0009-0000-0000-0000224884CF Message-Id: <20190422063231.51043-2-huntbag@linux.vnet.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:,, definitions=2019-04-21_08:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 malwarescore=0 suspectscore=0 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1810050000 definitions=main-1904220049 Sender: linux-pm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pm@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Currently, the cpuidle governors determine what idle state a idling CPU should enter into based on heuristics that depend on the idle history on that CPU. Given that no predictive heuristic is perfect, there are cases where the governor predicts a shallow idle state, hoping that the CPU will be busy soon. However, if no new workload is scheduled on that CPU in the near future, the CPU will end up in the shallow state. In case of POWER, this is problematic, when the predicted state in the aforementioned scenario is a lite stop state, as such lite states will inhibit SMT folding, thereby depriving the other threads in the core from using the core resources. So we do not want to get stucked in such states for longer duration. To address this, the cpuidle-core can queue timer to correspond with the residency value of the next available state. This timer will forcefully wakeup the cpu. Few such iterations will essentially train the governor to select a deeper state for that cpu, as the timer here corresponds to the next available cpuidle state residency. Cpu will be kicked out of the lite state and end up in a non-lite state. Signed-off-by: Abhishek Goel --- arch/powerpc/include/asm/opal-api.h | 1 + drivers/cpuidle/cpuidle-powernv.c | 71 ++++++++++++++++++++++++++++- 2 files changed, 71 insertions(+), 1 deletion(-) diff --git a/arch/powerpc/include/asm/opal-api.h b/arch/powerpc/include/asm/opal-api.h index 870fb7b23..735dec731 100644 --- a/arch/powerpc/include/asm/opal-api.h +++ b/arch/powerpc/include/asm/opal-api.h @@ -226,6 +226,7 @@ */ #define OPAL_PM_TIMEBASE_STOP 0x00000002 +#define OPAL_PM_LOSE_USER_CONTEXT 0x00001000 #define OPAL_PM_LOSE_HYP_CONTEXT 0x00002000 #define OPAL_PM_LOSE_FULL_CONTEXT 0x00004000 #define OPAL_PM_NAP_ENABLED 0x00010000 diff --git a/drivers/cpuidle/cpuidle-powernv.c b/drivers/cpuidle/cpuidle-powernv.c index 84b1ebe21..30b877962 100644 --- a/drivers/cpuidle/cpuidle-powernv.c +++ b/drivers/cpuidle/cpuidle-powernv.c @@ -15,6 +15,7 @@ #include #include #include +#include #include #include @@ -43,6 +44,40 @@ struct stop_psscr_table { static struct stop_psscr_table stop_psscr_table[CPUIDLE_STATE_MAX] __read_mostly; +DEFINE_PER_CPU(struct hrtimer, forced_wakeup_timer); + +static int forced_wakeup_time_compute(struct cpuidle_device *dev, + struct cpuidle_driver *drv, + int index) +{ + int i, timeout_us = 0; + + for (i = index + 1; i < drv->state_count; i++) { + if (drv->states[i].disabled || dev->states_usage[i].disable) + continue; + timeout_us = drv->states[i].target_residency + + 2 * drv->states[i].exit_latency; + break; + } + + return timeout_us; +} + +enum hrtimer_restart forced_wakeup_hrtimer_callback(struct hrtimer *hrtimer) +{ + return HRTIMER_NORESTART; +} + +static void forced_wakeup_timer_init(int cpu, struct cpuidle_driver *drv) +{ + struct hrtimer *cpu_forced_wakeup_timer = &per_cpu(forced_wakeup_timer, + cpu); + + hrtimer_init(cpu_forced_wakeup_timer, CLOCK_MONOTONIC, + HRTIMER_MODE_REL); + cpu_forced_wakeup_timer->function = forced_wakeup_hrtimer_callback; +} + static u64 default_snooze_timeout __read_mostly; static bool snooze_timeout_en __read_mostly; @@ -103,6 +138,28 @@ static int snooze_loop(struct cpuidle_device *dev, return index; } +static int stop_lite_loop(struct cpuidle_device *dev, + struct cpuidle_driver *drv, + int index) +{ + int timeout_us; + struct hrtimer *this_timer = &per_cpu(forced_wakeup_timer, dev->cpu); + + timeout_us = forced_wakeup_time_compute(dev, drv, index); + + if (timeout_us > 0) + hrtimer_start(this_timer, ns_to_ktime(timeout_us * 1000), + HRTIMER_MODE_REL_PINNED); + + power9_idle_type(stop_psscr_table[index].val, + stop_psscr_table[index].mask); + + if (unlikely(hrtimer_is_queued(this_timer))) + hrtimer_cancel(this_timer); + + return index; +} + static int nap_loop(struct cpuidle_device *dev, struct cpuidle_driver *drv, int index) @@ -190,7 +247,7 @@ static int powernv_cpuidle_cpu_dead(unsigned int cpu) */ static int powernv_cpuidle_driver_init(void) { - int idle_state; + int idle_state, cpu; struct cpuidle_driver *drv = &powernv_idle_driver; drv->state_count = 0; @@ -224,6 +281,9 @@ static int powernv_cpuidle_driver_init(void) drv->cpumask = (struct cpumask *)cpu_present_mask; + for_each_cpu(cpu, drv->cpumask) + forced_wakeup_timer_init(cpu, drv); + return 0; } @@ -299,6 +359,7 @@ static int powernv_add_idle_states(void) for (i = 0; i < dt_idle_states; i++) { unsigned int exit_latency, target_residency; bool stops_timebase = false; + bool lose_user_context = false; struct pnv_idle_states_t *state = &pnv_idle_states[i]; /* @@ -324,6 +385,9 @@ static int powernv_add_idle_states(void) if (has_stop_states && !(state->valid)) continue; + if (state->flags & OPAL_PM_LOSE_USER_CONTEXT) + lose_user_context = true; + if (state->flags & OPAL_PM_TIMEBASE_STOP) stops_timebase = true; @@ -332,6 +396,11 @@ static int powernv_add_idle_states(void) add_powernv_state(nr_idle_states, "Nap", CPUIDLE_FLAG_NONE, nap_loop, target_residency, exit_latency, 0, 0); + } else if (has_stop_states && !lose_user_context) { + add_powernv_state(nr_idle_states, state->name, + CPUIDLE_FLAG_NONE, stop_lite_loop, + target_residency, exit_latency, + state->psscr_val, state->psscr_mask); } else if (has_stop_states && !stops_timebase) { add_powernv_state(nr_idle_states, state->name, CPUIDLE_FLAG_NONE, stop_loop,