diff options
Diffstat (limited to 'arch/powerpc/platforms/cell/spufs/sched.c')
-rw-r--r-- | arch/powerpc/platforms/cell/spufs/sched.c | 54 |
1 files changed, 45 insertions, 9 deletions
diff --git a/arch/powerpc/platforms/cell/spufs/sched.c b/arch/powerpc/platforms/cell/spufs/sched.c index d673353b6d3..1b2916bdc1c 100644 --- a/arch/powerpc/platforms/cell/spufs/sched.c +++ b/arch/powerpc/platforms/cell/spufs/sched.c @@ -44,10 +44,6 @@ #include <asm/spu_priv1.h> #include "spufs.h" -#define SPU_TIMESLICE (HZ) - -#define SPUSCHED_TICK (HZ / 100) - struct spu_prio_array { DECLARE_BITMAP(bitmap, MAX_PRIO); struct list_head runq[MAX_PRIO]; @@ -60,6 +56,46 @@ static struct spu_prio_array *spu_prio; static struct task_struct *spusched_task; static struct timer_list spusched_timer; +/* + * Priority of a normal, non-rt, non-niced'd process (aka nice level 0). + */ +#define NORMAL_PRIO 120 + +/* + * Frequency of the spu scheduler tick. By default we do one SPU scheduler + * tick for every 10 CPU scheduler ticks. + */ +#define SPUSCHED_TICK (10) + +/* + * These are the 'tuning knobs' of the scheduler: + * + * Minimum timeslice is 5 msecs (or 10 jiffies, whichever is larger), + * default timeslice is 100 msecs, maximum timeslice is 800 msecs. + */ +#define MIN_SPU_TIMESLICE max(5 * HZ / 100, 10) +#define DEF_SPU_TIMESLICE (100 * HZ / 100) + +#define MAX_USER_PRIO (MAX_PRIO - MAX_RT_PRIO) +#define SCALE_PRIO(x, prio) \ + max(x * (MAX_PRIO - prio) / (MAX_USER_PRIO / 2), MIN_SPU_TIMESLICE) + +/* + * scale user-nice values [ -20 ... 0 ... 19 ] to time slice values: + * [800ms ... 100ms ... 5ms] + * + * The higher a thread's priority, the bigger timeslices + * it gets during one round of execution. But even the lowest + * priority thread gets MIN_TIMESLICE worth of execution time. + */ +void spu_set_timeslice(struct spu_context *ctx) +{ + if (ctx->prio < NORMAL_PRIO) + ctx->time_slice = SCALE_PRIO(DEF_SPU_TIMESLICE * 4, ctx->prio); + else + ctx->time_slice = SCALE_PRIO(DEF_SPU_TIMESLICE, ctx->prio); +} + static inline int node_allowed(int node) { cpumask_t mask; @@ -265,8 +301,8 @@ static struct spu *find_victim(struct spu_context *ctx) list_for_each_entry(spu, &spu_prio->active_list[node], list) { struct spu_context *tmp = spu->ctx; - if (tmp->rt_priority < ctx->rt_priority && - (!victim || tmp->rt_priority < victim->rt_priority)) + if (tmp->prio > ctx->prio && + (!victim || tmp->prio > victim->prio)) victim = spu->ctx; } mutex_unlock(&spu_prio->active_mutex[node]); @@ -333,7 +369,7 @@ int spu_activate(struct spu_context *ctx, unsigned long flags) * If this is a realtime thread we try to get it running by * preempting a lower priority thread. */ - if (!spu && ctx->rt_priority) + if (!spu && rt_prio(ctx->prio)) spu = find_victim(ctx); if (spu) { spu_bind_context(spu, ctx); @@ -424,7 +460,7 @@ void spu_yield(struct spu_context *ctx) static void spusched_tick(struct spu_context *ctx) { - if (ctx->policy != SCHED_RR || --ctx->time_slice) + if (ctx->policy == SCHED_FIFO || --ctx->time_slice) return; /* @@ -448,7 +484,7 @@ static void spusched_tick(struct spu_context *ctx) */ wake_up(&ctx->stop_wq); } - ctx->time_slice = SPU_DEF_TIMESLICE; + spu_set_timeslice(ctx); mutex_unlock(&ctx->state_mutex); } else { ctx->time_slice++; |