From patchwork Sun Aug 6 16:22:41 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Meng Xu X-Patchwork-Id: 9883865 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 28DE56031B for ; Sun, 6 Aug 2017 16:25:57 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 19BA3285AE for ; Sun, 6 Aug 2017 16:25:57 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 0E5FF285B5; Sun, 6 Aug 2017 16:25:57 +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=-4.2 required=2.0 tests=BAYES_00, RCVD_IN_DNSWL_MED autolearn=ham version=3.3.1 Received: from lists.xenproject.org (lists.xenproject.org [192.237.175.120]) (using TLSv1.2 with cipher AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id 49B3D285AE for ; Sun, 6 Aug 2017 16:25:56 +0000 (UTC) Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.84_2) (envelope-from ) id 1deOKj-0007Ip-3H; Sun, 06 Aug 2017 16:23:17 +0000 Received: from mail6.bemta3.messagelabs.com ([195.245.230.39]) by lists.xenproject.org with esmtp (Exim 4.84_2) (envelope-from ) id 1deOKh-0007ID-B7 for xen-devel@lists.xen.org; Sun, 06 Aug 2017 16:23:15 +0000 Received: from [85.158.137.68] by server-2.bemta-3.messagelabs.com id BF/5A-22472-27247895; Sun, 06 Aug 2017 16:23:14 +0000 X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFvrCLMWRWlGSWpSXmKPExsUyr8m9UbfQqT3 SYN16HYslHxezODB6HN39mymAMYo1My8pvyKBNaP33Gamgn+xFT+Pf2ZrYDzq1sXIxSEkMINJ YtHh+0xdjJwcbAIqEsc3PGIFsUUEpCWufb7MCGIzC2xglLh9NgbEFhawk5j3Zi9YPYuAqsTtM y/AbF4BZ4kN26+yg9gSAnISJ49NBpvDKeAi8e/PGRYQWwio5vG2DawQNaESaxafZ4Kpf/zwAe MERp4FjAyrGDWKU4vKUot0jUz0kooy0zNKchMzc3QNDYz1clOLixPTU3MSk4r1kvNzNzEC/V7 PwMC4g/HVcb9DjJIcTEqivPEr2iKF+JLyUyozEosz4otKc1KLDzHKcHAoSfA6OrZHCgkWpaan VqRl5gADECYtwcGjJMK7HSTNW1yQmFucmQ6ROsVozPFqwv9vTBxN3z9+ZxJiycvPS5US5xUAK RUAKc0ozYMbBIuMS4yyUsK8jAwMDEI8BalFuZklqPKvGMU5GJWEeYVBpvBk5pXA7XsFdAoT0C lvEltBTilJREhJNTDq+lyZxuln6hPawianx2G254HwimXHgze+sr22kzVzUv08od2lEy97Gtg eqbDWduSK1CwSUrVu/J4o/HB902db5Sn/g0/ZOzVpBB0ylbz1NUWVVSPvR4dxj4vHsr7vL1de tps34UnAuuTi6DjWp2U19+5EfJvZpjZr+86Tvs4tm58f/JC5IViJpTgj0VCLuag4EQDQEn9bh wIAAA== X-Env-Sender: mengxu@cis.upenn.edu X-Msg-Ref: server-13.tower-31.messagelabs.com!1502036593!104227214!1 X-Originating-IP: [158.130.71.129] X-SpamReason: No, hits=0.5 required=7.0 tests=BODY_RANDOM_LONG X-StarScan-Received: X-StarScan-Version: 9.4.25; banners=-,-,- X-VirusChecked: Checked Received: (qmail 6530 invoked from network); 6 Aug 2017 16:23:13 -0000 Received: from renard.seas.upenn.edu (HELO fox.seas.upenn.edu) (158.130.71.129) by server-13.tower-31.messagelabs.com with SMTP; 6 Aug 2017 16:23:13 -0000 Received: from panda-catbroadwell.cis.upenn.edu (SEASnet-48-12.cis.upenn.edu [158.130.48.13]) (authenticated bits=0) by fox.seas.upenn.edu (8.15.2/8.14.5) with ESMTPSA id v76GMxOo022037 (version=TLSv1.2 cipher=AES256-SHA256 bits=256 verify=NOT); Sun, 6 Aug 2017 12:23:00 -0400 From: Meng Xu To: xen-devel@lists.xen.org Date: Sun, 6 Aug 2017 12:22:41 -0400 Message-Id: <1502036563-4275-2-git-send-email-mengxu@cis.upenn.edu> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1502036563-4275-1-git-send-email-mengxu@cis.upenn.edu> References: <1502036563-4275-1-git-send-email-mengxu@cis.upenn.edu> X-Proofpoint-Virus-Version: vendor=nai engine=5600 definitions=5800 signatures=585085 X-Proofpoint-Spam-Reason: safe Cc: george.dunlap@eu.citrix.com, dario.faggioli@citrix.com, ian.jackson@eu.citrix.com, xumengpanda@gmail.com, Meng Xu , wei.liu@citrix.com Subject: [Xen-devel] [PATCH v1 1/3] xen:rtds: towards work conserving RTDS X-BeenThere: xen-devel@lists.xen.org X-Mailman-Version: 2.1.18 Precedence: list List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Errors-To: xen-devel-bounces@lists.xen.org Sender: "Xen-devel" X-Virus-Scanned: ClamAV using ClamSMTP Make RTDS scheduler work conserving without breaking the real-time guarantees. VCPU model: Each real-time VCPU is extended to have an extratime flag and a priority_level field. When a VCPU's budget is depleted in the current period, if it has extratime flag set, its priority_level will increase by 1 and its budget will be refilled; othewrise, the VCPU will be moved to the depletedq. Scheduling policy is modified global EDF: A VCPU v1 has higher priority than another VCPU v2 if (i) v1 has smaller priority_leve; or (ii) v1 has the same priority_level but has a smaller deadline Queue management: Run queue holds VCPUs with extratime flag set and VCPUs with remaining budget. Run queue is sorted in increasing order of VCPUs priorities. Depleted queue holds VCPUs which have extratime flag cleared and depleted budget. Replenished queue is not modified. Signed-off-by: Meng Xu --- Changes from RFC v1 Rewording comments and commit message Remove is_work_conserving field from rt_vcpu structure Use one bit in VCPU's flag to indicate if a VCPU will have extra time Correct comments style --- xen/common/sched_rt.c | 90 ++++++++++++++++++++++++++++++++++++++------- xen/include/public/domctl.h | 3 ++ 2 files changed, 79 insertions(+), 14 deletions(-) diff --git a/xen/common/sched_rt.c b/xen/common/sched_rt.c index 39f6bee..4e048b9 100644 --- a/xen/common/sched_rt.c +++ b/xen/common/sched_rt.c @@ -49,13 +49,15 @@ * A PCPU is feasible if the VCPU can run on this PCPU and (the PCPU is idle or * has a lower-priority VCPU running on it.) * - * Each VCPU has a dedicated period and budget. + * Each VCPU has a dedicated period, budget and a extratime flag * The deadline of a VCPU is at the end of each period; * A VCPU has its budget replenished at the beginning of each period; * While scheduled, a VCPU burns its budget. * The VCPU needs to finish its budget before its deadline in each period; * The VCPU discards its unused budget at the end of each period. - * If a VCPU runs out of budget in a period, it has to wait until next period. + * When a VCPU runs out of budget in a period, if its extratime flag is set, + * the VCPU increases its priority_level by 1 and refills its budget; otherwise, + * it has to wait until next period. * * Each VCPU is implemented as a deferable server. * When a VCPU has a task running on it, its budget is continuously burned; @@ -63,7 +65,8 @@ * * Queue scheme: * A global runqueue and a global depletedqueue for each CPU pool. - * The runqueue holds all runnable VCPUs with budget, sorted by deadline; + * The runqueue holds all runnable VCPUs with budget, + * sorted by priority_level and deadline; * The depletedqueue holds all VCPUs without budget, unsorted; * * Note: cpumask and cpupool is supported. @@ -151,6 +154,14 @@ #define RTDS_depleted (1<<__RTDS_depleted) /* + * RTDS_extratime: Can the vcpu run in the time that is + * not part of any real-time reservation, and would therefore + * be otherwise left idle? + */ +#define __RTDS_extratime 4 +#define RTDS_extratime (1<<__RTDS_extratime) + +/* * rt tracing events ("only" 512 available!). Check * include/public/trace.h for more details. */ @@ -201,6 +212,8 @@ struct rt_vcpu { struct rt_dom *sdom; struct vcpu *vcpu; + unsigned priority_level; + unsigned flags; /* mark __RTDS_scheduled, etc.. */ }; @@ -245,6 +258,11 @@ static inline struct list_head *rt_replq(const struct scheduler *ops) return &rt_priv(ops)->replq; } +static inline bool has_extratime(const struct rt_vcpu *svc) +{ + return (svc->flags & RTDS_extratime) ? 1 : 0; +} + /* * Helper functions for manipulating the runqueue, the depleted queue, * and the replenishment events queue. @@ -274,6 +292,21 @@ vcpu_on_replq(const struct rt_vcpu *svc) } /* + * If v1 priority >= v2 priority, return value > 0 + * Otherwise, return value < 0 + */ +static s_time_t +compare_vcpu_priority(const struct rt_vcpu *v1, const struct rt_vcpu *v2) +{ + int prio = v2->priority_level - v1->priority_level; + + if ( prio == 0 ) + return v2->cur_deadline - v1->cur_deadline; + + return prio; +} + +/* * Debug related code, dump vcpu/cpu information */ static void @@ -303,6 +336,7 @@ rt_dump_vcpu(const struct scheduler *ops, const struct rt_vcpu *svc) cpulist_scnprintf(keyhandler_scratch, sizeof(keyhandler_scratch), mask); printk("[%5d.%-2u] cpu %u, (%"PRI_stime", %"PRI_stime")," " cur_b=%"PRI_stime" cur_d=%"PRI_stime" last_start=%"PRI_stime"\n" + " \t\t priority_level=%d has_extratime=%d\n" " \t\t onQ=%d runnable=%d flags=%x effective hard_affinity=%s\n", svc->vcpu->domain->domain_id, svc->vcpu->vcpu_id, @@ -312,6 +346,8 @@ rt_dump_vcpu(const struct scheduler *ops, const struct rt_vcpu *svc) svc->cur_budget, svc->cur_deadline, svc->last_start, + svc->priority_level, + has_extratime(svc), vcpu_on_q(svc), vcpu_runnable(svc->vcpu), svc->flags, @@ -423,15 +459,18 @@ rt_update_deadline(s_time_t now, struct rt_vcpu *svc) */ svc->last_start = now; svc->cur_budget = svc->budget; + svc->priority_level = 0; /* TRACE */ { struct __packed { unsigned vcpu:16, dom:16; + unsigned priority_level; uint64_t cur_deadline, cur_budget; } d; d.dom = svc->vcpu->domain->domain_id; d.vcpu = svc->vcpu->vcpu_id; + d.priority_level = svc->priority_level; d.cur_deadline = (uint64_t) svc->cur_deadline; d.cur_budget = (uint64_t) svc->cur_budget; trace_var(TRC_RTDS_BUDGET_REPLENISH, 1, @@ -454,7 +493,7 @@ rt_update_deadline(s_time_t now, struct rt_vcpu *svc) * cases, if the vcpu with the earliest deadline is what we * are dealing with). */ -static inline bool_t +static inline bool deadline_queue_remove(struct list_head *queue, struct list_head *elem) { int pos = 0; @@ -466,7 +505,7 @@ deadline_queue_remove(struct list_head *queue, struct list_head *elem) return !pos; } -static inline bool_t +static inline bool deadline_queue_insert(struct rt_vcpu * (*qelem)(struct list_head *), struct rt_vcpu *svc, struct list_head *elem, struct list_head *queue) @@ -477,7 +516,7 @@ deadline_queue_insert(struct rt_vcpu * (*qelem)(struct list_head *), list_for_each ( iter, queue ) { struct rt_vcpu * iter_svc = (*qelem)(iter); - if ( svc->cur_deadline <= iter_svc->cur_deadline ) + if ( compare_vcpu_priority(svc, iter_svc) > 0 ) break; pos++; } @@ -537,8 +576,9 @@ runq_insert(const struct scheduler *ops, struct rt_vcpu *svc) ASSERT( !vcpu_on_q(svc) ); ASSERT( vcpu_on_replq(svc) ); - /* add svc to runq if svc still has budget */ - if ( svc->cur_budget > 0 ) + /* add svc to runq if svc still has budget or its extratime is set */ + if ( svc->cur_budget > 0 || + has_extratime(svc) ) deadline_runq_insert(svc, &svc->q_elem, runq); else list_add(&svc->q_elem, &prv->depletedq); @@ -857,6 +897,8 @@ rt_alloc_vdata(const struct scheduler *ops, struct vcpu *vc, void *dd) svc->vcpu = vc; svc->last_start = 0; + __set_bit(__RTDS_extratime, &svc->flags); + svc->priority_level = 0; svc->period = RTDS_DEFAULT_PERIOD; if ( !is_idle_vcpu(vc) ) svc->budget = RTDS_DEFAULT_BUDGET; @@ -966,8 +1008,16 @@ burn_budget(const struct scheduler *ops, struct rt_vcpu *svc, s_time_t now) if ( svc->cur_budget <= 0 ) { - svc->cur_budget = 0; - __set_bit(__RTDS_depleted, &svc->flags); + if ( has_extratime(svc) ) + { + svc->priority_level++; + svc->cur_budget = svc->budget; + } + else + { + svc->cur_budget = 0; + __set_bit(__RTDS_depleted, &svc->flags); + } } /* TRACE */ @@ -976,11 +1026,15 @@ burn_budget(const struct scheduler *ops, struct rt_vcpu *svc, s_time_t now) unsigned vcpu:16, dom:16; uint64_t cur_budget; int delta; + unsigned priority_level; + bool has_extratime; } d; d.dom = svc->vcpu->domain->domain_id; d.vcpu = svc->vcpu->vcpu_id; d.cur_budget = (uint64_t) svc->cur_budget; d.delta = delta; + d.priority_level = svc->priority_level; + d.has_extratime = svc->flags & RTDS_extratime; trace_var(TRC_RTDS_BUDGET_BURN, 1, sizeof(d), (unsigned char *) &d); @@ -1088,7 +1142,7 @@ rt_schedule(const struct scheduler *ops, s_time_t now, bool_t tasklet_work_sched vcpu_runnable(current) && scurr->cur_budget > 0 && ( is_idle_vcpu(snext->vcpu) || - scurr->cur_deadline <= snext->cur_deadline ) ) + compare_vcpu_priority(scurr, snext) > 0 ) ) snext = scurr; } @@ -1198,13 +1252,13 @@ runq_tickle(const struct scheduler *ops, struct rt_vcpu *new) } iter_svc = rt_vcpu(iter_vc); if ( latest_deadline_vcpu == NULL || - iter_svc->cur_deadline > latest_deadline_vcpu->cur_deadline ) + compare_vcpu_priority(iter_svc, latest_deadline_vcpu) < 0 ) latest_deadline_vcpu = iter_svc; } /* 3) candicate has higher priority, kick out lowest priority vcpu */ if ( latest_deadline_vcpu != NULL && - new->cur_deadline < latest_deadline_vcpu->cur_deadline ) + compare_vcpu_priority(latest_deadline_vcpu, new) < 0 ) { SCHED_STAT_CRANK(tickled_busy_cpu); cpu_to_tickle = latest_deadline_vcpu->vcpu->processor; @@ -1395,6 +1449,10 @@ rt_dom_cntl( svc = rt_vcpu(d->vcpu[local_sched.vcpuid]); local_sched.u.rtds.budget = svc->budget / MICROSECS(1); local_sched.u.rtds.period = svc->period / MICROSECS(1); + if ( has_extratime(svc) ) + local_sched.u.rtds.flags |= XEN_DOMCTL_SCHED_RTDS_extratime; + else + local_sched.u.rtds.flags &= ~XEN_DOMCTL_SCHED_RTDS_extratime; spin_unlock_irqrestore(&prv->lock, flags); if ( copy_to_guest_offset(op->u.v.vcpus, index, @@ -1419,6 +1477,10 @@ rt_dom_cntl( svc = rt_vcpu(d->vcpu[local_sched.vcpuid]); svc->period = period; svc->budget = budget; + if ( local_sched.u.rtds.flags & XEN_DOMCTL_SCHED_RTDS_extratime ) + __set_bit(__RTDS_extratime, &svc->flags); + else + __clear_bit(__RTDS_extratime, &svc->flags); spin_unlock_irqrestore(&prv->lock, flags); } /* Process a most 64 vCPUs without checking for preemptions. */ @@ -1493,7 +1555,7 @@ static void repl_timer_handler(void *data){ { struct rt_vcpu *next_on_runq = q_elem(runq->next); - if ( svc->cur_deadline > next_on_runq->cur_deadline ) + if ( compare_vcpu_priority(svc, next_on_runq) < 0 ) runq_tickle(ops, next_on_runq); } else if ( __test_and_clear_bit(__RTDS_depleted, &svc->flags) && diff --git a/xen/include/public/domctl.h b/xen/include/public/domctl.h index 0669c31..ba5daa9 100644 --- a/xen/include/public/domctl.h +++ b/xen/include/public/domctl.h @@ -360,6 +360,9 @@ typedef struct xen_domctl_sched_credit2 { typedef struct xen_domctl_sched_rtds { uint32_t period; uint32_t budget; +#define _XEN_DOMCTL_SCHED_RTDS_extratime 0 +#define XEN_DOMCTL_SCHED_RTDS_extratime (1U<<_XEN_DOMCTL_SCHED_RTDS_extratime) + uint32_t flags; } xen_domctl_sched_rtds_t; typedef struct xen_domctl_schedparam_vcpu {