Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758233AbXK0E75 (ORCPT ); Mon, 26 Nov 2007 23:59:57 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1756684AbXK0E7n (ORCPT ); Mon, 26 Nov 2007 23:59:43 -0500 Received: from e2.ny.us.ibm.com ([32.97.182.142]:44378 "EHLO e2.ny.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756804AbXK0E7l (ORCPT ); Mon, 26 Nov 2007 23:59:41 -0500 Date: Tue, 27 Nov 2007 10:42:31 +0530 From: Srivatsa Vaddagiri To: Ingo Molnar Cc: dmitry.adamushko@gmail.com, a.p.zijlstra@chello.nl, dhaval@linux.vnet.ibm.com, linux-kernel@vger.kernel.org, efault@gmx.de, skumar@linux.vnet.ibm.com, Balbir Singh , Dipankar Subject: [Patch 3/5 v2] sched: change how cpu load is calculated Message-ID: <20071127051231.GE20083@linux.vnet.ibm.com> Reply-To: vatsa@linux.vnet.ibm.com References: <20071119123051.GC28777@linux.vnet.ibm.com> <20071119131201.GB31491@elte.hu> <20071119150312.GA2365@linux.vnet.ibm.com> <20071119152258.GB31426@elte.hu> <20071119160647.GV3359@linux.vnet.ibm.com> <20071119190057.GA12650@elte.hu> <20071126050044.GA5304@linux.vnet.ibm.com> <20071126050905.GF5304@linux.vnet.ibm.com> <20071126202836.GA17012@elte.hu> <20071127050652.GA20083@linux.vnet.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20071127050652.GA20083@linux.vnet.ibm.com> User-Agent: Mutt/1.5.11 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 5158 Lines: 182 This patch changes how the cpu load exerted by fair_sched_class tasks is calculated. Load exerted by fair_sched_class tasks on a cpu is now a summation of the group weights, rather than summation of task weights. Weight exerted by a group on a cpu is dependent on the shares allocated to it. This version of patch (v2 of Patch 3/5) has a minor impact on code size (but should have no runtime/functional impact) for !CONFIG_FAIR_GROUP_SCHED case, but the overall code, IMHO, is neater compared to v1 of Patch 3/5 (because of lesser #ifdefs). I prefer v2 of Patch 3/5. Signed-off-by: Srivatsa Vaddagiri --- kernel/sched.c | 27 +++++++++++---------------- kernel/sched_fair.c | 31 +++++++++++++++++++++++++++---- kernel/sched_rt.c | 2 ++ 3 files changed, 40 insertions(+), 20 deletions(-) Index: current/kernel/sched.c =================================================================== --- current.orig/kernel/sched.c +++ current/kernel/sched.c @@ -870,6 +870,16 @@ iter_move_one_task(struct rq *this_rq, i struct rq_iterator *iterator); #endif +static inline void inc_cpu_load(struct rq *rq, unsigned long load) +{ + update_load_add(&rq->load, load); +} + +static inline void dec_cpu_load(struct rq *rq, unsigned long load) +{ + update_load_sub(&rq->load, load); +} + #include "sched_stats.h" #include "sched_idletask.c" #include "sched_fair.c" @@ -880,26 +890,14 @@ iter_move_one_task(struct rq *this_rq, i #define sched_class_highest (&rt_sched_class) -static inline void inc_load(struct rq *rq, const struct task_struct *p) -{ - update_load_add(&rq->load, p->se.load.weight); -} - -static inline void dec_load(struct rq *rq, const struct task_struct *p) -{ - update_load_sub(&rq->load, p->se.load.weight); -} - static void inc_nr_running(struct task_struct *p, struct rq *rq) { rq->nr_running++; - inc_load(rq, p); } static void dec_nr_running(struct task_struct *p, struct rq *rq) { rq->nr_running--; - dec_load(rq, p); } static void set_load_weight(struct task_struct *p) @@ -4071,10 +4069,8 @@ void set_user_nice(struct task_struct *p goto out_unlock; } on_rq = p->se.on_rq; - if (on_rq) { + if (on_rq) dequeue_task(rq, p, 0); - dec_load(rq, p); - } p->static_prio = NICE_TO_PRIO(nice); set_load_weight(p); @@ -4084,7 +4080,6 @@ void set_user_nice(struct task_struct *p if (on_rq) { enqueue_task(rq, p, 0); - inc_load(rq, p); /* * If the task increased its priority or is running and * lowered its priority, then reschedule its CPU: Index: current/kernel/sched_fair.c =================================================================== --- current.orig/kernel/sched_fair.c +++ current/kernel/sched_fair.c @@ -755,15 +755,26 @@ static inline struct sched_entity *paren static void enqueue_task_fair(struct rq *rq, struct task_struct *p, int wakeup) { struct cfs_rq *cfs_rq; - struct sched_entity *se = &p->se; + struct sched_entity *se = &p->se, *topse = NULL; + int incload = 1; for_each_sched_entity(se) { - if (se->on_rq) + topse = se; + if (se->on_rq) { + incload = 0; break; + } cfs_rq = cfs_rq_of(se); enqueue_entity(cfs_rq, se, wakeup); wakeup = 1; } + /* + * Increment cpu load if we just enqueued the first task of a group on + * 'rq->cpu'. 'topse' represents the group to which task 'p' belongs + * at the highest grouping level. + */ + if (incload) + inc_cpu_load(rq, topse->load.weight); } /* @@ -774,16 +785,28 @@ static void enqueue_task_fair(struct rq static void dequeue_task_fair(struct rq *rq, struct task_struct *p, int sleep) { struct cfs_rq *cfs_rq; - struct sched_entity *se = &p->se; + struct sched_entity *se = &p->se, *topse = NULL; + int decload = 1; for_each_sched_entity(se) { + topse = se; cfs_rq = cfs_rq_of(se); dequeue_entity(cfs_rq, se, sleep); /* Don't dequeue parent if it has other entities besides us */ - if (cfs_rq->load.weight) + if (cfs_rq->load.weight) { + if (parent_entity(se)) + decload = 0; break; + } sleep = 1; } + /* + * Decrement cpu load if we just dequeued the last task of a group on + * 'rq->cpu'. 'topse' represents the group to which task 'p' belongs + * at the highest grouping level. + */ + if (decload) + dec_cpu_load(rq, topse->load.weight); } /* Index: current/kernel/sched_rt.c =================================================================== --- current.orig/kernel/sched_rt.c +++ current/kernel/sched_rt.c @@ -31,6 +31,7 @@ static void enqueue_task_rt(struct rq *r list_add_tail(&p->run_list, array->queue + p->prio); __set_bit(p->prio, array->bitmap); + inc_cpu_load(rq, p->se.load.weight); } /* @@ -45,6 +46,7 @@ static void dequeue_task_rt(struct rq *r list_del(&p->run_list); if (list_empty(array->queue + p->prio)) __clear_bit(p->prio, array->bitmap); + dec_cpu_load(rq, p->se.load.weight); } /* -- Regards, vatsa - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/