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SMP - CPU local run queues

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- each CPU has its own runqueues

- processes on BSP are put on the runqueues later after a switch to
  the final stack when cpuid works to avoid special cases

- enqueue() and dequeue() use the run queues of the cpu the process is
  assigned to

- pick_proc() uses the local run queues

- printing of per-CPU run queues ('2') on serial console
This commit is contained in:
Tomas Hruby 2010-09-15 14:10:18 +00:00
parent ad73a4f50c
commit fac5fbfdbf
10 changed files with 134 additions and 60 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

6
kernel/arch/i386/arch_smp.c
View file

@ -215,8 +215,12 @@ PRIVATE void ap_finish_booting(void)
}
printf("CPU %d local APIC timer is ticking\n", cpu);
/* FIXME assign CPU local idle structure */
get_cpulocal_var(proc_ptr) = proc_addr(IDLE);
get_cpulocal_var(bill_ptr) = proc_addr(IDLE);
BKL_UNLOCK();
ap_boot_finished(cpu);
spinlock_unlock(&boot_lock);
for(;;);

29
kernel/arch/i386/arch_system.c
View file

@ -370,19 +370,38 @@ PUBLIC void do_ser_debug()
ser_debug(c);
}
PRIVATE void ser_dump_queues(void)
PRIVATE void ser_dump_queue_cpu(unsigned cpu)
{
int q;
struct proc ** rdy_head;
rdy_head = get_cpu_var(cpu, run_q_head);
for(q = 0; q < NR_SCHED_QUEUES; q++) {
struct proc *p;
if(rdy_head[q])
if(rdy_head[q]) {
printf("%2d: ", q);
for(p = rdy_head[q]; p; p = p->p_nextready) {
printf("%s / %d ", p->p_name, p->p_endpoint);
for(p = rdy_head[q]; p; p = p->p_nextready) {
printf("%s / %d ", p->p_name, p->p_endpoint);
}
printf("\n");
}
printf("\n");
}
}
PRIVATE void ser_dump_queues(void)
{
#ifdef CONFIG_SMP
unsigned cpu;
printf("--- run queues ---\n");
for (cpu = 0; cpu < ncpus; cpu++) {
printf("CPU %d :\n", cpu);
ser_dump_queue_cpu(cpu);
}
#else
ser_dump_queue_cpu(0);
#endif
}
PRIVATE void ser_dump_segs(void)

2
kernel/arch/i386/glo.h
View file

@ -2,7 +2,7 @@
#define __GLO_X86_H__
#include "kernel/kernel.h"
#include "proto.h"
#include "arch_proto.h"
EXTERN int cpu_has_tsc; /* signal whether this cpu has time stamp register. This
feature was introduced by Pentium */

2
kernel/clock.c
View file

@ -194,6 +194,7 @@ PRIVATE void load_update(void)
u16_t slot;
int enqueued = 0, q;
struct proc *p;
struct proc **rdy_head;
/* Load average data is stored as a list of numbers in a circular
* buffer. Each slot accumulates _LOAD_UNIT_SECS of samples of
@ -207,6 +208,7 @@ PRIVATE void load_update(void)
kloadinfo.proc_last_slot = slot;
}
rdy_head = get_cpulocal_var(run_q_head);
/* Cumulation. How many processes are ready now? */
for(q = 0; q < NR_SCHED_QUEUES; q++) {
for(p = rdy_head[q]; p != NULL; p = p->p_nextready) {

5
kernel/cpulocals.h
View file

@ -5,6 +5,7 @@
#ifndef __ASSEMBLY__
#include "kernel.h"
#include "proc.h"
#ifdef CONFIG_SMP
@ -68,6 +69,10 @@ DECLARE_CPULOCAL(int, pagefault_handled);
*/
DECLARE_CPULOCAL(struct proc *, ptproc);
/* CPU private run queues */
DECLARE_CPULOCAL(struct proc *, run_q_head[NR_SCHED_QUEUES]); /* ptrs to ready list headers */
DECLARE_CPULOCAL(struct proc *, run_q_tail[NR_SCHED_QUEUES]); /* ptrs to ready list tails */
DECLARE_CPULOCAL_END
#endif /* __ASSEMBLY__ */

34
kernel/debug.c
View file

@ -14,11 +14,14 @@
#define MAX_LOOP (NR_PROCS + NR_TASKS)
PUBLIC int
runqueues_ok(void)
PUBLIC int runqueues_ok_cpu(unsigned cpu)
{
int q, l = 0;
register struct proc *xp;
struct proc **rdy_head, **rdy_tail;
rdy_head = get_cpu_var(cpu, run_q_head);
rdy_tail = get_cpu_var(cpu, run_q_tail);
for (xp = BEG_PROC_ADDR; xp < END_PROC_ADDR; ++xp) {
xp->p_found = 0;
@ -109,6 +112,33 @@ runqueues_ok(void)
return 1;
}
#ifdef CONFIG_SMP
PRIVATE int runqueues_ok_all(void)
{
unsigned c;
for (c = 0 ; c < ncpus; c++) {
if (!runqueues_ok_cpu(c))
return 0;
}
return 1;
}
PUBLIC int runqueues_ok(void)
{
return runqueues_ok_all();
}
#else
PUBLIC int runqueues_ok(void)
{
return runqueues_ok_cpu(0);
}
#endif
PUBLIC char *
rtsflagstr(const int flags)
{

22
kernel/main.c
View file

@ -32,8 +32,10 @@
/* Prototype declarations for PRIVATE functions. */
FORWARD _PROTOTYPE( void announce, (void));
void ser_dump_queues(void);
PUBLIC void bsp_finish_booting(void)
{
int i;
#if SPROFILE
sprofiling = 0; /* we're not profiling until instructed to */
#endif /* SPROFILE */
@ -49,6 +51,13 @@ PUBLIC void bsp_finish_booting(void)
get_cpulocal_var(bill_ptr) = proc_addr(IDLE); /* it has to point somewhere */
announce(); /* print MINIX startup banner */
/*
* we have access to the cpu local run queue, only now schedule the processes.
* We ignore the slots for the former kernel tasks
*/
for (i=0; i < NR_BOOT_PROCS - NR_TASKS; i++) {
RTS_UNSET(proc_addr(i), RTS_PROC_STOP);
}
/*
* enable timer interrupts and clock task on the boot CPU
*/
@ -75,8 +84,10 @@ PUBLIC void bsp_finish_booting(void)
cycles_accounting_init();
DEBUGEXTRA(("done\n"));
assert(runqueues_ok());
#ifdef CONFIG_SMP
cpu_set_flag(bsp_cpu_id, CPU_IS_READY);
#endif
switch_to_user();
NOT_REACHABLE;
}
@ -246,11 +257,10 @@ PUBLIC int main(void)
* done this; until then, don't let it run.
*/
if(ip->flags & PROC_FULLVM)
RTS_SET(rp, RTS_VMINHIBIT);
rp->p_rts_flags |= RTS_VMINHIBIT;
/* None of the kernel tasks run */
if (rp->p_nr < 0) RTS_SET(rp, RTS_PROC_STOP);
RTS_UNSET(rp, RTS_SLOT_FREE); /* remove RTS_SLOT_FREE and schedule */
rp->p_rts_flags |= RTS_PROC_STOP;
rp->p_rts_flags &= ~RTS_SLOT_FREE;
alloc_segments(rp);
DEBUGEXTRA(("done\n"));
}

86
kernel/proc.c
View file

@ -110,6 +110,18 @@ PUBLIC void proc_init(void)
}
}
PRIVATE void switch_address_space_idle(void)
{
#ifdef CONFIG_SMP
/*
* currently we bet that VM is always alive and its pages available so
* when the CPU wakes up the kernel is mapped and no surprises happen.
* This is only a problem if more than 1 cpus are available
*/
switch_address_space(proc_addr(VM_PROC_NR));
#endif
}
/*===========================================================================*
* idle *
*===========================================================================*/
@ -121,6 +133,8 @@ PRIVATE void idle(void)
* the CPU utiliziation of certain workloads with high precision.
*/
switch_address_space_idle();
/* start accounting for the idle time */
context_stop(proc_addr(KERNEL));
halt_cpu();
@ -1209,19 +1223,21 @@ PUBLIC void enqueue(
* responsible for inserting a process into one of the scheduling queues.
* The mechanism is implemented here. The actual scheduling policy is
* defined in sched() and pick_proc().
*
* This function can be used x-cpu as it always uses the queues of the cpu the
* process is assigned to.
*/
int q = rp->p_priority; /* scheduling queue to use */
struct proc * p;
#if DEBUG_RACE
/* With DEBUG_RACE, schedule everyone at the same priority level. */
rp->p_priority = q = MIN_USER_Q;
#endif
struct proc **rdy_head, **rdy_tail;
assert(proc_is_runnable(rp));
assert(q >= 0);
rdy_head = get_cpu_var(rp->p_cpu, run_q_head);
rdy_tail = get_cpu_var(rp->p_cpu, run_q_tail);
/* Now add the process to the queue. */
if (!rdy_head[q]) { /* add to empty queue */
rdy_head[q] = rdy_tail[q] = rp; /* create a new queue */
@ -1245,7 +1261,7 @@ PUBLIC void enqueue(
RTS_SET(p, RTS_PREEMPTED); /* calls dequeue() */
#if DEBUG_SANITYCHECKS
assert(runqueues_ok());
assert(runqueues_ok_local());
#endif
}
@ -1262,6 +1278,8 @@ PRIVATE void enqueue_head(struct proc *rp)
{
const int q = rp->p_priority; /* scheduling queue to use */
struct proc **rdy_head, **rdy_tail;
assert(proc_ptr_ok(rp));
assert(proc_is_runnable(rp));
@ -1274,6 +1292,9 @@ PRIVATE void enqueue_head(struct proc *rp)
assert(q >= 0);
rdy_head = get_cpu_var(rp->p_cpu, run_q_head);
rdy_tail = get_cpu_var(rp->p_cpu, run_q_tail);
/* Now add the process to the queue. */
if (!rdy_head[q]) { /* add to empty queue */
rdy_head[q] = rdy_tail[q] = rp; /* create a new queue */
@ -1284,7 +1305,7 @@ PRIVATE void enqueue_head(struct proc *rp)
rdy_head[q] = rp; /* set new queue head */
#if DEBUG_SANITYCHECKS
assert(runqueues_ok());
assert(runqueues_ok_local());
#endif
}
@ -1297,23 +1318,31 @@ PUBLIC void dequeue(const struct proc *rp)
/* A process must be removed from the scheduling queues, for example, because
* it has blocked. If the currently active process is removed, a new process
* is picked to run by calling pick_proc().
*
* This function can operate x-cpu as it always removes the process from the
* queue of the cpu the process is currently assigned to.
*/
register int q = rp->p_priority; /* queue to use */
register struct proc **xpp; /* iterate over queue */
register struct proc *prev_xp;
struct proc **rdy_tail;
assert(proc_ptr_ok(rp));
assert(!proc_is_runnable(rp));
/* Side-effect for kernel: check if the task's stack still is ok? */
assert (!iskernelp(rp) || *priv(rp)->s_stack_guard == STACK_GUARD);
rdy_tail = get_cpu_var(rp->p_cpu, run_q_tail);
/* Now make sure that the process is not in its ready queue. Remove the
* process if it is found. A process can be made unready even if it is not
* running by being sent a signal that kills it.
*/
prev_xp = NULL;
for (xpp = &rdy_head[q]; *xpp; xpp = &(*xpp)->p_nextready) {
for (xpp = get_cpu_var_ptr(rp->p_cpu, run_q_head[q]); *xpp;
xpp = &(*xpp)->p_nextready) {
if (*xpp == rp) { /* found process to remove */
*xpp = (*xpp)->p_nextready; /* replace with next chain */
if (rp == rdy_tail[q]) { /* queue tail removed */
@ -1326,36 +1355,10 @@ PUBLIC void dequeue(const struct proc *rp)
}
#if DEBUG_SANITYCHECKS
assert(runqueues_ok());
assert(runqueues_ok_local());
#endif
}
#if DEBUG_RACE
/*===========================================================================*
* random_process *
*===========================================================================*/
PRIVATE struct proc *random_process(struct proc *head)
{
int i, n = 0;
struct proc *rp;
u64_t r;
read_tsc_64(&r);
for(rp = head; rp; rp = rp->p_nextready)
n++;
/* Use low-order word of TSC as pseudorandom value. */
i = r.lo % n;
for(rp = head; i--; rp = rp->p_nextready)
;
assert(rp);
return rp;
}
#endif
/*===========================================================================*
* pick_proc *
*===========================================================================*/
@ -1364,26 +1367,23 @@ PRIVATE struct proc * pick_proc(void)
/* Decide who to run now. A new process is selected an returned.
* When a billable process is selected, record it in 'bill_ptr', so that the
* clock task can tell who to bill for system time.
*
* This functions always uses the run queues of the local cpu!
*/
register struct proc *rp; /* process to run */
struct proc **rdy_head;
int q; /* iterate over queues */
/* Check each of the scheduling queues for ready processes. The number of
* queues is defined in proc.h, and priorities are set in the task table.
* The lowest queue contains IDLE, which is always ready.
*/
rdy_head = get_cpulocal_var(run_q_head);
for (q=0; q < NR_SCHED_QUEUES; q++) {
if(!(rp = rdy_head[q])) {
TRACE(VF_PICKPROC, printf("queue %d empty\n", q););
continue;
}
#if DEBUG_RACE
rp = random_process(rdy_head[q]);
#endif
TRACE(VF_PICKPROC, printf("found %s / %d on queue %d\n",
rp->p_name, rp->p_endpoint, q););
assert(proc_is_runnable(rp));
if (priv(rp)->s_flags & BILLABLE)
get_cpulocal_var(bill_ptr) = rp; /* bill for system time */

2
kernel/proc.h
View file

@ -252,8 +252,6 @@ struct proc {
#ifndef __ASSEMBLY__
EXTERN struct proc proc[NR_TASKS + NR_PROCS]; /* process table */
EXTERN struct proc *rdy_head[NR_SCHED_QUEUES]; /* ptrs to ready list headers */
EXTERN struct proc *rdy_tail[NR_SCHED_QUEUES]; /* ptrs to ready list tails */
_PROTOTYPE( int mini_send, (struct proc *caller_ptr, endpoint_t dst_e,
message *m_ptr, int flags));

6
kernel/proto.h
View file

@ -102,6 +102,12 @@ _PROTOTYPE( int disable_irq, (const irq_hook_t *hook) );
/* debug.c */
_PROTOTYPE( int runqueues_ok, (void) );
#ifndef CONFIG_SMP
#define runqueues_ok_local runqueues_ok
#else
#define runqueues_ok_local() runqueues_ok_cpu(cpuid)
_PROTOTYPE( int runqueues_ok_cpu, (unsigned cpu));
#endif
_PROTOTYPE( char *rtsflagstr, (int flags) );
_PROTOTYPE( char *miscflagstr, (int flags) );
_PROTOTYPE( char *schedulerstr, (struct proc *scheduler) );