From owner-freebsd-arch  Sun Jan 26 11:20:28 2003
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Date: Sun, 26 Jan 2003 11:20:24 -0800 (PST)
From: Matthew Dillon <dillon@apollo.backplane.com>
Message-Id: <200301261920.h0QJKOBB051946@apollo.backplane.com>
To: Jeff Roberson <jroberson@chesapeake.net>,
	Steve Kargl <sgk@troutmask.apl.washington.edu>,
	Robert Watson <rwatson@FreeBSD.ORG>,
	Gary Jennejohn <garyj@jennejohn.org>, <arch@FreeBSD.ORG>
Subject: Re: New scheduler - Interactivity fixes
References: <20030126035429.A64928-100000@mail.chesapeake.net> <200301261913.h0QJDd8c051876@apollo.backplane.com>
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X-Loop: FreeBSD.ORG

    Oops, a few mistakes with my pseudo-code.  Corrected below (ok, it IS only
    pseudo code but still...).  (note also: GlobalAgg could also be a
    per-cpu Agg).

    sched_clock()
    {
	task->slice -= GlobalAgg + task->priority;	<<< must include task's
	if (task->slice < 0)				    own priority here.
		involuntary_switch();
    }

    sched_choose()
    {
	while ((task = RemoveHead(queue)) != NULL) {
	    if (task->slice >= 0) {
		GlobalAgg -= task->priority;	<<<< task removed from queue
		break;
	    }
	    task->slice += task->priority * NOMINAL_TICKS;	(usually 4)
	    AddTail(queue, task);
	}
	return(task);
    }


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