Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S272002AbTHDRNQ (ORCPT ); Mon, 4 Aug 2003 13:13:16 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S272004AbTHDRNP (ORCPT ); Mon, 4 Aug 2003 13:13:15 -0400 Received: from 224.Red-217-125-129.pooles.rima-tde.net ([217.125.129.224]:54764 "HELO cocodriloo.com") by vger.kernel.org with SMTP id S272002AbTHDRMH (ORCPT ); Mon, 4 Aug 2003 13:12:07 -0400 Date: Mon, 4 Aug 2003 21:15:13 +0200 From: Antonio Vargas To: Con Kolivas Cc: linux kernel mailing list , Andrew Morton , Ingo Molnar , Felipe Alfaro Solana Subject: Re: [PATCH] O13int for interactivity Message-ID: <20030804191513.GB814@wind.cocodriloo.com> References: <200308050207.18096.kernel@kolivas.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <200308050207.18096.kernel@kolivas.org> User-Agent: Mutt/1.3.28i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 6636 Lines: 192 On Tue, Aug 05, 2003 at 02:07:18AM +1000, Con Kolivas wrote: > Changes: > > Reverted the child penalty to 95 as new changes help this from hurting > > Changed the logic behind loss of interactive credits to those that burn off > all their sleep_avg > > Now all tasks get proportionately more sleep as their relative bonus drops > off. This has the effect of detecting a change from a cpu burner to an > interactive task more rapidly as in O10. > > The _major_ change in this patch is that tasks on uninterruptible sleep do not > earn any sleep avg during that sleep; it is not voluntary sleep so they should > not get it. This has the effect of stopping cpu hogs from gaining dynamic > priority during periods of heavy I/O. Very good for the jerks you may > see in X or audio skips when you start a whole swag of disk intensive cpu hogs > (eg make -j large number). I've simply dropped all their sleep_avg, but > weighting it may be more appropriate. This has the side effect that pure > disk tasks (eg cp) have relatively low priority which is why weighting may > be better. We shall see. > > Please test this one extensively. It should _not_ affect I/O throughput per > se, but I'd like to see some of the I/O benchmarks on this. I do not want to > have detrimental effects elsewhere. > > patch-O12.3-O13int applies on top of 2.6.0-test2-mm4 that has been > patched with O12.3int and is available on my site, and a full patch > against 2.6.0-test2 called patch-test2-O13int is here: > > http://kernel.kolivas.org/2.5 > > patch-O12.3-O13int: > > --- linux-2.6.0-test2-mm4-O12.3/kernel/sched.c 2003-08-05 01:30:27.000000000 +1000 > +++ linux-2.6.0-test2-mm4-O13/kernel/sched.c 2003-08-05 01:36:20.000000000 +1000 > @@ -78,7 +78,7 @@ > #define MAX_TIMESLICE (200 * HZ / 1000) > #define TIMESLICE_GRANULARITY (HZ/40 ?: 1) > #define ON_RUNQUEUE_WEIGHT 30 > -#define CHILD_PENALTY 90 > +#define CHILD_PENALTY 95 > #define PARENT_PENALTY 100 > #define EXIT_WEIGHT 3 > #define PRIO_BONUS_RATIO 25 > @@ -365,6 +365,9 @@ static void recalc_task_prio(task_t *p, > unsigned long long __sleep_time = now - p->timestamp; > unsigned long sleep_time; > > + if (!p->sleep_avg) > + p->interactive_credit--; > + > if (__sleep_time > NS_MAX_SLEEP_AVG) > sleep_time = NS_MAX_SLEEP_AVG; > else > @@ -384,17 +387,19 @@ static void recalc_task_prio(task_t *p, > JIFFIES_TO_NS(JUST_INTERACTIVE_SLEEP(p)); > else { > /* > - * Tasks with interactive credits get boosted more > - * rapidly if their bonus has dropped off. Other > - * tasks are limited to one timeslice worth of > - * sleep avg. > + * The lower the sleep avg a task has the more > + * rapidly it will rise with sleep time. Tasks > + * without interactive_credit are limited to > + * one timeslice worth of sleep avg bonus. > */ > - if (p->interactive_credit > 0) > - sleep_time *= (MAX_BONUS + 1 - > + sleep_time *= (MAX_BONUS + 1 - > (NS_TO_JIFFIES(p->sleep_avg) * > MAX_BONUS / MAX_SLEEP_AVG)); > - else if (sleep_time > JIFFIES_TO_NS(task_timeslice(p))) > - sleep_time = JIFFIES_TO_NS(task_timeslice(p)); > + > + if (p->interactive_credit < 0 && > + sleep_time > JIFFIES_TO_NS(task_timeslice(p))) > + sleep_time = > + JIFFIES_TO_NS(task_timeslice(p)); > > /* > * This code gives a bonus to interactive tasks. > @@ -435,20 +440,26 @@ static inline void activate_task(task_t > recalc_task_prio(p, now); > > /* > - * Tasks which were woken up by interrupts (ie. hw events) > - * are most likely of interactive nature. So we give them > - * the credit of extending their sleep time to the period > - * of time they spend on the runqueue, waiting for execution > - * on a CPU, first time around: > + * This checks to make sure it's not an uninterruptible task > + * that is now waking up. > */ > - if (in_interrupt()) > - p->activated = 2; > - else > - /* > - * Normal first-time wakeups get a credit too for on-runqueue time, > - * but it will be weighted down: > - */ > - p->activated = 1; > + if (!p->activated){ [1] > + /* > + * Tasks which were woken up by interrupts (ie. hw events) > + * are most likely of interactive nature. So we give them > + * the credit of extending their sleep time to the period > + * of time they spend on the runqueue, waiting for execution > + * on a CPU, first time around: > + */ > + if (in_interrupt()) > + p->activated = 2; > + else > + /* > + * Normal first-time wakeups get a credit too for on-runqueue > + * time, but it will be weighted down: > + */ > + p->activated = 1; [3] > + } > > p->timestamp = now; > > @@ -572,8 +583,15 @@ repeat_lock_task: > task_rq_unlock(rq, &flags); > goto repeat_lock_task; > } > - if (old_state == TASK_UNINTERRUPTIBLE) > + if (old_state == TASK_UNINTERRUPTIBLE){ > + /* > + * Tasks on involuntary sleep don't earn > + * sleep_avg > + */ > rq->nr_uninterruptible--; > + p->timestamp = sched_clock(); > + p->activated = -1; [2] > + } > if (sync) > __activate_task(p, rq); > else { > @@ -1326,7 +1344,6 @@ void scheduler_tick(int user_ticks, int > p->prio = effective_prio(p); > p->time_slice = task_timeslice(p); > p->first_time_slice = 0; > - p->interactive_credit--; > > if (!rq->expired_timestamp) > rq->expired_timestamp = jiffies; > @@ -1459,7 +1476,7 @@ pick_next_task: > queue = array->queue + idx; > next = list_entry(queue->next, task_t, run_list); > > - if (next->activated && next->interactive_credit > 0) { > + if (next->activated > 0) { > unsigned long long delta = now - next->timestamp; > > if (next->activated == 1) > Con, I will probably be wrong, but in [1] you are testing "activated != 0" and [2] is setting "activated = -1", which _is_ != 0 and thus would enter the "if->else" branch and do "activated = 1" in [3]. Perhaps you meant to set "activated = 0" in [2]??? Note I've not read the rest of the scheduler code, so perhaps the "activated = 0" is in another place... just in case, I prefer asking. Greets for your hard work, Antonio. -- 1. Dado un programa, siempre tiene al menos un fallo. 2. Dadas varias lineas de codigo, siempre se pueden acortar a menos lineas. 3. Por induccion, todos los programas se pueden reducir a una linea que no funciona. - 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/