/* * Copyright (c) 2000 Apple Computer, Inc. All rights reserved. * * @APPLE_LICENSE_HEADER_START@ * * The contents of this file constitute Original Code as defined in and * are subject to the Apple Public Source License Version 1.1 (the * "License"). You may not use this file except in compliance with the * License. Please obtain a copy of the License at * http://www.apple.com/publicsource and read it before using this file. * * This Original Code and all software distributed under the License are * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES, * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY, * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT. Please see the * License for the specific language governing rights and limitations * under the License. * * @APPLE_LICENSE_HEADER_END@ */ /* * @OSF_COPYRIGHT@ */ /* * Mach Operating System * Copyright (c) 1991,1990,1989,1988,1987 Carnegie Mellon University * All Rights Reserved. * * Permission to use, copy, modify and distribute this software and its * documentation is hereby granted, provided that both the copyright * notice and this permission notice appear in all copies of the * software, derivative works or modified versions, and any portions * thereof, and that both notices appear in supporting documentation. * * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS" * CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE. * * Carnegie Mellon requests users of this software to return to * * Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU * School of Computer Science * Carnegie Mellon University * Pittsburgh PA 15213-3890 * * any improvements or extensions that they make and grant Carnegie Mellon * the rights to redistribute these changes. */ /* */ /* * File: clock_prim.c * Author: Avadis Tevanian, Jr. * Date: 1986 * * Clock primitives. */ #include <cpus.h> #include <mach/boolean.h> #include <mach/kern_return.h> #include <mach/machine.h> #include <kern/host.h> #include <kern/mach_param.h> #include <kern/sched.h> #include <kern/spl.h> #include <kern/thread.h> #include <kern/processor.h> #include <machine/machparam.h> #include <kern/sf.h> #include <kern/mk_sp.h> /*** ??? fix so this can be removed ***/ /*** ??? Should this file be MK SP-specific? Or is it more general purpose? ***/ /* * USAGE_THRESHOLD is the amount by which usage must change to * cause a priority shift that moves a thread between run queues. */ #ifdef PRI_SHIFT_2 #if PRI_SHIFT_2 > 0 #define USAGE_THRESHOLD (((1 << PRI_SHIFT) + (1 << PRI_SHIFT_2)) << (2 + SCHED_SHIFT)) #else /* PRI_SHIFT_2 > 0 */ #define USAGE_THRESHOLD (((1 << PRI_SHIFT) - (1 << -(PRI_SHIFT_2))) << (2 + SCHED_SHIFT)) #endif /* PRI_SHIFT_2 > 0 */ #else /* PRI_SHIFT_2 */ #define USAGE_THRESHOLD (1 << (PRI_SHIFT + 2 + SCHED_SHIFT)) #endif /* PRI_SHIFT_2 */ /* * thread_quantum_update: * * Recalculate the quantum and priority for a thread. * The number of ticks that has elapsed since we were last called * is passed as "nticks." */ void thread_quantum_update( register int mycpu, register thread_t thread, int nticks, int state) { register int quantum; register processor_t myprocessor; register processor_set_t pset; spl_t s; myprocessor = cpu_to_processor(mycpu); pset = myprocessor->processor_set; /* * Account for thread's utilization of these ticks. * This assumes that there is *always* a current thread. * When the processor is idle, it should be the idle thread. */ /* * Update set_quantum and calculate the current quantum. */ pset->set_quantum = pset->machine_quantum[ (pset->runq.count > pset->processor_count) ? pset->processor_count : pset->runq.count]; if (myprocessor->runq.count != 0) quantum = min_quantum; else quantum = pset->set_quantum; /* * Now recompute the priority of the thread if appropriate. */ { s = splsched(); thread_lock(thread); if (!(thread->policy & (POLICY_TIMESHARE|POLICY_RR|POLICY_FIFO))) { thread_unlock(thread); splx(s); return; } if (thread->state&TH_IDLE) { /* Don't try to time-slice idle threads */ myprocessor->first_quantum = TRUE; if (thread->sched_stamp != sched_tick) update_priority(thread); thread_unlock(thread); splx(s); ast_check(); return; } myprocessor->quantum -= nticks; /* * Runtime quantum adjustment. Use quantum_adj_index * to avoid synchronizing quantum expirations. */ if ( quantum != myprocessor->last_quantum && pset->processor_count > 1 ) { myprocessor->last_quantum = quantum; simple_lock(&pset->quantum_adj_lock); quantum = min_quantum + (pset->quantum_adj_index * (quantum - min_quantum)) / (pset->processor_count - 1); if (++(pset->quantum_adj_index) >= pset->processor_count) pset->quantum_adj_index = 0; simple_unlock(&pset->quantum_adj_lock); } if (myprocessor->quantum <= 0) { if (thread->sched_stamp != sched_tick) update_priority(thread); else if ( thread->policy == POLICY_TIMESHARE && thread->depress_priority < 0 ) { thread_timer_delta(thread); thread->sched_usage += thread->sched_delta; thread->sched_delta = 0; compute_my_priority(thread); } /* * This quantum is up, give this thread another. */ myprocessor->first_quantum = FALSE; if (thread->policy == POLICY_TIMESHARE) myprocessor->quantum += quantum; else myprocessor->quantum += min_quantum; } /* * Recompute priority if appropriate. */ else { if (thread->sched_stamp != sched_tick) update_priority(thread); else if ( thread->policy == POLICY_TIMESHARE && thread->depress_priority < 0 ) { thread_timer_delta(thread); if (thread->sched_delta >= USAGE_THRESHOLD) { thread->sched_usage += thread->sched_delta; thread->sched_delta = 0; compute_my_priority(thread); } } } thread_unlock(thread); splx(s); /* * Check for and schedule ast if needed. */ ast_check(); } }