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Remove outdated comments, and historical CCPU_SHIFT. Make resched_cpu static, 

const-ify ccpu.  Note: resched_cpu is not correct, should be revisited.

OK by <ad>.
This commit is contained in:
rmind 2008-07-02 19:44:10 +00:00
parent 61fc86b29b
commit 73f3b7bb31
3 changed files with 12 additions and 54 deletions
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60
sys/kern/kern_synch.c
View File

@ -1,4 +1,4 @@
/* $NetBSD: kern_synch.c,v 1.249 2008/07/02 19:38:37 rmind Exp $ */
/* $NetBSD: kern_synch.c,v 1.250 2008/07/02 19:44:10 rmind Exp $ */
/*-
* Copyright (c) 1999, 2000, 2004, 2006, 2007, 2008 The NetBSD Foundation, Inc.
@ -68,7 +68,7 @@
*/
#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: kern_synch.c,v 1.249 2008/07/02 19:38:37 rmind Exp $");
__KERNEL_RCSID(0, "$NetBSD: kern_synch.c,v 1.250 2008/07/02 19:44:10 rmind Exp $");
#include "opt_kstack.h"
#include "opt_perfctrs.h"
@ -101,6 +101,7 @@ __KERNEL_RCSID(0, "$NetBSD: kern_synch.c,v 1.249 2008/07/02 19:38:37 rmind Exp $
static u_int sched_unsleep(struct lwp *, bool);
static void sched_changepri(struct lwp *, pri_t);
static void sched_lendpri(struct lwp *, pri_t);
static void resched_cpu(struct lwp *);
syncobj_t sleep_syncobj = {
SOBJ_SLEEPQ_SORTED,
@ -1066,30 +1067,12 @@ sched_unsleep(struct lwp *l, bool cleanup)
panic("sched_unsleep");
}
void
static void
resched_cpu(struct lwp *l)
{
struct cpu_info *ci;
struct cpu_info *ci = ci = l->l_cpu;
/*
* XXXSMP
* Since l->l_cpu persists across a context switch,
* this gives us *very weak* processor affinity, in
* that we notify the CPU on which the process last
* ran that it should try to switch.
*
* This does not guarantee that the process will run on
* that processor next, because another processor might
* grab it the next time it performs a context switch.
*
* This also does not handle the case where its last
* CPU is running a higher-priority process, but every
* other CPU is running a lower-priority process. There
* are ways to handle this situation, but they're not
* currently very pretty, and we also need to weigh the
* cost of moving a process from one CPU to another.
*/
ci = l->l_cpu;
KASSERT(lwp_locked(l, NULL));
if (lwp_eprio(l) > ci->ci_schedstate.spc_curpriority)
cpu_need_resched(ci, 0);
}
@ -1135,22 +1118,8 @@ syncobj_noowner(wchan_t wchan)
return NULL;
}
/* decay 95% of `p_pctcpu' in 60 seconds; see CCPU_SHIFT before changing */
fixpt_t ccpu = 0.95122942450071400909 * FSCALE; /* exp(-1/20) */
/*
* If `ccpu' is not equal to `exp(-1/20)' and you still want to use the
* faster/more-accurate formula, you'll have to estimate CCPU_SHIFT below
* and possibly adjust FSHIFT in "param.h" so that (FSHIFT >= CCPU_SHIFT).
*
* To estimate CCPU_SHIFT for exp(-1/20), the following formula was used:
* 1 - exp(-1/20) ~= 0.0487 ~= 0.0488 == 1 (fixed pt, *11* bits).
*
* If you dont want to bother with the faster/more-accurate formula, you
* can set CCPU_SHIFT to (FSHIFT + 1) which will use a slower/less-accurate
* (more general) method of calculating the %age of CPU used by a process.
*/
#define CCPU_SHIFT (FSHIFT + 1)
/* Decay 95% of proc::p_pctcpu in 60 seconds, ccpu = exp(-1/20) */
const fixpt_t ccpu = 0.95122942450071400909 * FSCALE;
/*
* sched_pstats:
@ -1180,9 +1149,8 @@ sched_pstats(void *arg)
continue;
/*
* Increment time in/out of memory and sleep time (if
* sleeping). We ignore overflow; with 16-bit int's
* (remember them?) overflow takes 45 days.
* Increment time in/out of memory and sleep
* time (if sleeping), ignore overflow.
*/
mutex_enter(p->p_lock);
runtm = p->p_rtime.sec;
@ -1201,16 +1169,8 @@ sched_pstats(void *arg)
lpctcpu = l->l_pctcpu;
lcpticks = atomic_swap_uint(&l->l_cpticks, 0);
#if (FSHIFT >= CCPU_SHIFT)
lpctcpu += (clkhz == 100) ?
((fixpt_t)lcpticks) <<
(FSHIFT - CCPU_SHIFT) :
100 * (((fixpt_t) p->p_cpticks)
<< (FSHIFT - CCPU_SHIFT)) / clkhz;
#else
lpctcpu += ((FSCALE - ccpu) *
(lcpticks * FSCALE / clkhz)) >> FSHIFT;
#endif
l->l_pctcpu = lpctcpu;
}
/* Calculating p_pctcpu only for ps(1) */

3
sys/sys/lwp.h
View File

@ -1,4 +1,4 @@
/* $NetBSD: lwp.h,v 1.103 2008/07/02 19:38:37 rmind Exp $ */
/* $NetBSD: lwp.h,v 1.104 2008/07/02 19:44:10 rmind Exp $ */
/*-
* Copyright (c) 2001, 2006, 2007, 2008 The NetBSD Foundation, Inc.
@ -281,7 +281,6 @@ void startlwp(void *);
void upcallret(lwp_t *);
void lwp_exit(lwp_t *) __dead;
void lwp_exit_switchaway(lwp_t *);
lwp_t *proc_representative_lwp(struct proc *, int *, int);
int lwp_suspend(lwp_t *, lwp_t *);
int lwp_create1(lwp_t *, const void *, size_t, u_long, lwpid_t *);
void lwp_update_creds(lwp_t *);

3
sys/sys/sched.h
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@ -1,4 +1,4 @@
/* $NetBSD: sched.h,v 1.62 2008/06/22 14:00:11 ad Exp $ */
/* $NetBSD: sched.h,v 1.63 2008/07/02 19:44:10 rmind Exp $ */
/*-
* Copyright (c) 1999, 2000, 2001, 2002, 2007, 2008 The NetBSD Foundation, Inc.
@ -265,7 +265,6 @@ void sched_print_runqueue(void (*pr)(const char *, ...));
bool kpreempt(uintptr_t);
void preempt(void);
int mi_switch(struct lwp *);
void resched_cpu(struct lwp *);
void updatertime(lwp_t *, const struct bintime *);
void sched_idle(void);