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m1/perf/sched.c: revamped to handle static registers correctly as well

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This commit is contained in:
Werner Almesberger 2011-09-21 17:44:52 -03:00
parent 05bbe9103b
commit 8f82a0e8d4
1 changed files with 85 additions and 31 deletions
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116
m1/perf/sched.c
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@ -62,10 +62,12 @@ struct insn {
} opa, opb, dest, cond;
int arity;
int latency;
int rmw; /* non-zero if instruction is read-modify-write */
int unresolved; /* number of data refs we need before we can sched */
int earliest; /* earliest cycle dependencies seen so far are met */
struct list dependants; /* list of dependencies (constant) */
int num_dependants; /* number of dependencies */
struct insn *next_setter; /* next setter of the same register */
#ifdef LCPF
int distance; /* minimum cycles on this path until the end */
#endif
@ -74,6 +76,7 @@ struct insn {
struct vm_reg {
struct insn *setter; /* instruction setting it; NULL if none */
struct insn *first_setter; /* first setter */
int pfpu_reg; /* underlying PFPU register */
int refs; /* usage count */
};
@ -95,6 +98,7 @@ static struct sched_ctx {
struct list unscheduled; /* unscheduled insns */
struct list waiting; /* insns waiting to be scheduled */
struct list ready[PFPU_PROGSIZE]; /* insns ready at nth cycle */
int cycle; /* the current cycle */
#ifdef REG_STATS
int max_regs, curr_regs; /* allocation statistics */
#endif
@ -233,20 +237,23 @@ static int alloc_reg(struct insn *setter)
int vm_reg, pfpu_reg, vm_idx;
vm_reg = setter->vm_insn->dest;
if (vm_reg >= 0)
return vm_reg;
reg = list_pop(&sc->unallocated);
if (!reg)
abort();
if (vm_reg >= 0) {
pfpu_reg = vm_reg;
sc->pfpu_regs[vm_reg].vm_reg = vm_reg; /* @@@ global init */
} else {
reg = list_pop(&sc->unallocated);
if (!reg)
abort();
#ifdef REG_STATS
sc->curr_regs++;
if (sc->curr_regs > sc->max_regs)
sc->max_regs = sc->curr_regs;
#endif
#ifdef REG_STATS
sc->curr_regs++;
if (sc->curr_regs > sc->max_regs)
sc->max_regs = sc->curr_regs;
#endif
reg->vm_reg = vm_reg;
pfpu_reg = reg-sc->pfpu_regs;
reg->vm_reg = vm_reg;
pfpu_reg = reg-sc->pfpu_regs;
}
Dprintf(" alloc reg %d -> %d\n", vm_reg, pfpu_reg);
@ -291,10 +298,20 @@ static void put_reg(int vm_reg)
}
static void put_reg_by_setter(struct insn *setter)
static void unblock(struct insn *insn);
static void put_reg_by_setter(struct insn *setter, int vm_reg)
{
if (setter)
struct vm_reg *reg;
if (setter) {
put_reg(setter->vm_insn->dest);
if (setter->next_setter)
unblock(setter->next_setter);
} else {
reg = sc->regs+vm_reg2idx(vm_reg);
if (reg->first_setter && !reg->first_setter->rmw)
unblock(reg->first_setter);
}
}
@ -347,7 +364,11 @@ static struct vm_reg *add_data_ref(struct insn *insn, struct data_ref *ref,
reg = sc->regs+vm_reg2idx(reg_num);
ref->insn = insn;
ref->dep = reg->setter;
if (ref->dep) {
if (insn->vm_insn->dest == reg_num)
insn->rmw = 1;
if (!ref->dep)
reg->refs++;
else {
list_add_tail(&ref->dep->dependants, &ref->more);
ref->dep->num_dependants++;
insn->unresolved++;
@ -364,6 +385,8 @@ static void init_scheduler(struct fpvm_fragment *frag)
{
int i;
struct insn *insn;
struct vm_reg *reg;
struct data_ref *ref;
list_init(&sc->unscheduled);
list_init(&sc->waiting);
@ -387,8 +410,20 @@ static void init_scheduler(struct fpvm_fragment *frag)
add_data_ref(insn, &insn->opa, frag->code[i].opa);
/* fall through */
case 0:
add_data_ref(insn,
&insn->dest, frag->code[i].dest)->setter = insn;
reg = sc->regs+vm_reg2idx(frag->code[i].dest);
if (reg->setter) {
reg->setter->next_setter = insn;
foreach (ref, &reg->setter->dependants)
if (ref->insn != insn)
insn->unresolved++;
if (!insn->rmw)
insn->unresolved++;
} else {
if (!insn->rmw)
insn->unresolved += reg->refs;
reg->first_setter = insn;
}
reg->setter = insn;
break;
default:
abort();
@ -413,6 +448,30 @@ static void init_scheduler(struct fpvm_fragment *frag)
}
static void unblock(struct insn *insn)
{
int slot;
assert(insn->unresolved);
if (--insn->unresolved)
return;
Dprintf(" unblocked %lu -> %u\n", insn-sc->insns, insn->earliest);
list_del(&insn->more);
slot = insn->earliest;
if (slot <= sc->cycle)
slot = sc->cycle+1;
list_add_tail(sc->ready+slot, &insn->more);
}
static void unblock_after(struct insn *insn, int cycle)
{
if (insn->earliest <= cycle)
insn->earliest = cycle+1;
unblock(insn);
}
static void issue(struct insn *insn, int cycle, unsigned *code)
{
struct data_ref *ref;
@ -425,14 +484,15 @@ static void issue(struct insn *insn, int cycle, unsigned *code)
switch (insn->arity) {
case 3:
put_reg_by_setter(insn->cond.dep, FPVM_REG_IFB);
/* fall through */
case 2:
CODE(cycle).opb = lookup_pfpu_reg(insn->vm_insn->opb);
put_reg_by_setter(insn->opb.dep);
put_reg_by_setter(insn->opb.dep, insn->vm_insn->opb);
/* fall through */
case 1:
CODE(cycle).opa = lookup_pfpu_reg(insn->vm_insn->opa);
put_reg_by_setter(insn->opa.dep);
put_reg_by_setter(insn->opa.dep, insn->vm_insn->opa);
break;
case 0:
break;
@ -443,18 +503,11 @@ static void issue(struct insn *insn, int cycle, unsigned *code)
CODE(end).dest = alloc_reg(insn);
CODE(cycle).opcode = fpvm_to_pfpu(insn->vm_insn->opcode);
foreach (ref, &insn->dependants) {
if (ref->insn->earliest <= end)
ref->insn->earliest = end+1;
assert(ref->insn->unresolved);
if (!--ref->insn->unresolved) {
Dprintf(" unlocked %lu -> %u\n", ref->insn-sc->insns,
ref->insn->earliest);
list_del(&ref->insn->more);
list_add_tail(sc->ready+ref->insn->earliest,
&ref->insn->more);
}
}
foreach (ref, &insn->dependants)
unblock_after(ref->insn, end);
if (insn->next_setter && !insn->next_setter->rmw)
unblock_after(insn->next_setter,
end-insn->next_setter->latency);
}
@ -485,6 +538,7 @@ static int schedule(unsigned int *code)
if (i == PFPU_PROGSIZE)
return -1;
sc->cycle = i;
Dprintf("@%d --- remaining %d, waiting %d + ready %d\n",
i, remaining, count(&sc->waiting), count(&sc->ready[i]));