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[CELL] cell: add placement computation for scheduling of affinity contexts 

This patch provides the spu affinity placement logic for the spufs scheduler.
Each time a gang is going to be scheduled, the placement of a reference
context is defined. The placement of all other contexts with affinity from
the gang is defined based on this reference context location and on a
precomputed displacement offset.

Signed-off-by: Andre Detsch <adetsch@br.ibm.com>
Signed-off-by: Arnd Bergmann <arnd.bergmann@de.ibm.com>
This commit is contained in:
Arnd Bergmann 2007-07-20 21:39:48 +02:00 committed by Arnd Bergmann
parent 8e68e2f248
commit c5fc8d2a92
3 changed files with 151 additions and 1 deletions
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4
arch/powerpc/platforms/cell/spufs/gang.c
View File

@ -75,8 +75,10 @@ void spu_gang_remove_ctx(struct spu_gang *gang, struct spu_context *ctx)
{
mutex_lock(&gang->mutex);
WARN_ON(ctx->gang != gang);
if (!list_empty(&ctx->aff_list))
if (!list_empty(&ctx->aff_list)) {
list_del_init(&ctx->aff_list);
gang->aff_flags &= ~AFF_OFFSETS_SET;
}
list_del_init(&ctx->gang_list);
gang->contexts--;
mutex_unlock(&gang->mutex);

142
arch/powerpc/platforms/cell/spufs/sched.c
View File

@ -233,6 +233,8 @@ static void spu_bind_context(struct spu *spu, struct spu_context *ctx)
if (ctx->flags & SPU_CREATE_NOSCHED)
atomic_inc(&cbe_spu_info[spu->node].reserved_spus);
if (!list_empty(&ctx->aff_list))
atomic_inc(&ctx->gang->aff_sched_count);
ctx->stats.slb_flt_base = spu->stats.slb_flt;
ctx->stats.class2_intr_base = spu->stats.class2_intr;
@ -259,6 +261,143 @@ static void spu_bind_context(struct spu *spu, struct spu_context *ctx)
spuctx_switch_state(ctx, SPU_UTIL_IDLE_LOADED);
}
/*
* XXX(hch): needs locking.
*/
static inline int sched_spu(struct spu *spu)
{
return (!spu->ctx || !(spu->ctx->flags & SPU_CREATE_NOSCHED));
}
static void aff_merge_remaining_ctxs(struct spu_gang *gang)
{
struct spu_context *ctx;
list_for_each_entry(ctx, &gang->aff_list_head, aff_list) {
if (list_empty(&ctx->aff_list))
list_add(&ctx->aff_list, &gang->aff_list_head);
}
gang->aff_flags |= AFF_MERGED;
}
static void aff_set_offsets(struct spu_gang *gang)
{
struct spu_context *ctx;
int offset;
offset = -1;
list_for_each_entry_reverse(ctx, &gang->aff_ref_ctx->aff_list,
aff_list) {
if (&ctx->aff_list == &gang->aff_list_head)
break;
ctx->aff_offset = offset--;
}
offset = 0;
list_for_each_entry(ctx, gang->aff_ref_ctx->aff_list.prev, aff_list) {
if (&ctx->aff_list == &gang->aff_list_head)
break;
ctx->aff_offset = offset++;
}
gang->aff_flags |= AFF_OFFSETS_SET;
}
static struct spu *aff_ref_location(struct spu_context *ctx, int mem_aff,
int group_size, int lowest_offset)
{
struct spu *spu;
int node, n;
/*
* TODO: A better algorithm could be used to find a good spu to be
* used as reference location for the ctxs chain.
*/
node = cpu_to_node(raw_smp_processor_id());
for (n = 0; n < MAX_NUMNODES; n++, node++) {
node = (node < MAX_NUMNODES) ? node : 0;
if (!node_allowed(ctx, node))
continue;
list_for_each_entry(spu, &cbe_spu_info[node].spus, cbe_list) {
if ((!mem_aff || spu->has_mem_affinity) &&
sched_spu(spu))
return spu;
}
}
return NULL;
}
static void aff_set_ref_point_location(struct spu_gang *gang)
{
int mem_aff, gs, lowest_offset;
struct spu_context *ctx;
struct spu *tmp;
mem_aff = gang->aff_ref_ctx->flags & SPU_CREATE_AFFINITY_MEM;
lowest_offset = 0;
gs = 0;
list_for_each_entry(tmp, &gang->aff_list_head, aff_list)
gs++;
list_for_each_entry_reverse(ctx, &gang->aff_ref_ctx->aff_list,
aff_list) {
if (&ctx->aff_list == &gang->aff_list_head)
break;
lowest_offset = ctx->aff_offset;
}
gang->aff_ref_spu = aff_ref_location(ctx, mem_aff, gs, lowest_offset);
}
static struct spu *ctx_location(struct spu *ref, int offset)
{
struct spu *spu;
spu = NULL;
if (offset >= 0) {
list_for_each_entry(spu, ref->aff_list.prev, aff_list) {
if (offset == 0)
break;
if (sched_spu(spu))
offset--;
}
} else {
list_for_each_entry_reverse(spu, ref->aff_list.next, aff_list) {
if (offset == 0)
break;
if (sched_spu(spu))
offset++;
}
}
return spu;
}
/*
* affinity_check is called each time a context is going to be scheduled.
* It returns the spu ptr on which the context must run.
*/
struct spu *affinity_check(struct spu_context *ctx)
{
struct spu_gang *gang;
if (list_empty(&ctx->aff_list))
return NULL;
gang = ctx->gang;
mutex_lock(&gang->aff_mutex);
if (!gang->aff_ref_spu) {
if (!(gang->aff_flags & AFF_MERGED))
aff_merge_remaining_ctxs(gang);
if (!(gang->aff_flags & AFF_OFFSETS_SET))
aff_set_offsets(gang);
aff_set_ref_point_location(gang);
}
mutex_unlock(&gang->aff_mutex);
if (!gang->aff_ref_spu)
return NULL;
return ctx_location(gang->aff_ref_spu, ctx->aff_offset);
}
/**
* spu_unbind_context - unbind spu context from physical spu
* @spu: physical spu to unbind from
@ -272,6 +411,9 @@ static void spu_unbind_context(struct spu *spu, struct spu_context *ctx)
if (spu->ctx->flags & SPU_CREATE_NOSCHED)
atomic_dec(&cbe_spu_info[spu->node].reserved_spus);
if (!list_empty(&ctx->aff_list))
if (atomic_dec_and_test(&ctx->gang->aff_sched_count))
ctx->gang->aff_ref_spu = NULL;
spu_switch_notify(spu, NULL);
spu_unmap_mappings(ctx);
spu_save(&ctx->csa, spu);

6
arch/powerpc/platforms/cell/spufs/spufs.h
View File

@ -112,6 +112,7 @@ struct spu_context {
struct list_head aff_list;
int aff_head;
int aff_offset;
};
struct spu_gang {
@ -124,6 +125,8 @@ struct spu_gang {
struct list_head aff_list_head;
struct mutex aff_mutex;
int aff_flags;
struct spu *aff_ref_spu;
atomic_t aff_sched_count;
};
/* Flag bits for spu_gang aff_flags */
@ -208,6 +211,9 @@ void spu_gang_add_ctx(struct spu_gang *gang, struct spu_context *ctx);
/* fault handling */
int spufs_handle_class1(struct spu_context *ctx);
/* affinity */
struct spu *affinity_check(struct spu_context *ctx);
/* context management */
extern atomic_t nr_spu_contexts;
static inline void spu_acquire(struct spu_context *ctx)