Re: [PATCH v2 0/7] Add new tracepoints required for EAS testing

[Qais Yousef]

On 05/13/19 14:28, Peter Zijlstra wrote:
> 
> 
> diff --git a/include/trace/events/sched.h b/include/trace/events/sched.h
> index c8c7c7efb487..11555f95a88e 100644
> --- a/include/trace/events/sched.h
> +++ b/include/trace/events/sched.h
> @@ -594,6 +594,23 @@ TRACE_EVENT(sched_wake_idle_without_ipi,
>  
>  	TP_printk("cpu=%d", __entry->cpu)
>  );
> +
> +/*
> + * Following tracepoints are not exported in tracefs and provide hooking
> + * mechanisms only for testing and debugging purposes.
> + */
> +DECLARE_TRACE(pelt_cfs_rq,
> +	TP_PROTO(struct cfs_rq *cfs_rq),
> +	TP_ARGS(cfs_rq));
> +
> +DECLARE_TRACE(pelt_se,
> +	TP_PROTO(struct sched_entity *se),
> +	TP_ARGS(se));
> +
> +DECLARE_TRACE(sched_overutilized,
> +	TP_PROTO(int overutilized),
> +	TP_ARGS(overutilized));
> +

If I decoded this patch correctly, what you're saying:

	1. Move struct cfs_rq to the exported sched.h header
	2. Get rid of the fatty wrapper functions and export any necessary
	   helper functions.
	3. No need for RT and DL pelt tracking at the moment.

I'm okay with this. The RT and DL might need to be revisited later but we don't
have immediate need for them now.

I'll add to this passing rd->span to sched_overutilizied.

Thanks

--
Qais Yousef

>  #endif /* _TRACE_SCHED_H */
>  
>  /* This part must be outside protection */
> diff --git a/kernel/sched/autogroup.c b/kernel/sched/autogroup.c
> index 2d4ff5353ded..2067080bb235 100644
> --- a/kernel/sched/autogroup.c
> +++ b/kernel/sched/autogroup.c
> @@ -259,7 +259,6 @@ void proc_sched_autogroup_show_task(struct task_struct *p, struct seq_file *m)
>  }
>  #endif /* CONFIG_PROC_FS */
>  
> -#ifdef CONFIG_SCHED_DEBUG
>  int autogroup_path(struct task_group *tg, char *buf, int buflen)
>  {
>  	if (!task_group_is_autogroup(tg))
> @@ -267,4 +266,3 @@ int autogroup_path(struct task_group *tg, char *buf, int buflen)
>  
>  	return snprintf(buf, buflen, "%s-%ld", "/autogroup", tg->autogroup->id);
>  }
> -#endif
> diff --git a/kernel/sched/core.c b/kernel/sched/core.c
> index 102dfcf0a29a..629bbf4f4247 100644
> --- a/kernel/sched/core.c
> +++ b/kernel/sched/core.c
> @@ -22,6 +22,14 @@
>  #define CREATE_TRACE_POINTS
>  #include <trace/events/sched.h>
>  
> +/*
> + * Export tracepoints that act as a bare tracehook (ie: have no trace event
> + * associated with them) to allow external modules to probe them.
> + */
> +EXPORT_TRACEPOINT_SYMBOL_GPL(pelt_cfs_rq);
> +EXPORT_TRACEPOINT_SYMBOL_GPL(pelt_se);
> +EXPORT_TRACEPOINT_SYMBOL_GPL(sched_overutilized);
> +
>  DEFINE_PER_CPU_SHARED_ALIGNED(struct rq, runqueues);
>  
>  #if defined(CONFIG_SCHED_DEBUG) && defined(CONFIG_JUMP_LABEL)
> diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
> index f35930f5e528..e7f82b1778b1 100644
> --- a/kernel/sched/fair.c
> +++ b/kernel/sched/fair.c
> @@ -3334,6 +3334,9 @@ static inline int propagate_entity_load_avg(struct sched_entity *se)
>  	update_tg_cfs_util(cfs_rq, se, gcfs_rq);
>  	update_tg_cfs_runnable(cfs_rq, se, gcfs_rq);
>  
> +	trace_pelt_cfs_rq(cfs_rq);
> +	trace_pelt_se(se);
> +
>  	return 1;
>  }
>  
> @@ -3486,6 +3489,8 @@ static void attach_entity_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *s
>  	add_tg_cfs_propagate(cfs_rq, se->avg.load_sum);
>  
>  	cfs_rq_util_change(cfs_rq, flags);
> +
> +	trace_pelt_cfs_rq(cfs_rq);
>  }
>  
>  /**
> @@ -3505,6 +3510,8 @@ static void detach_entity_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *s
>  	add_tg_cfs_propagate(cfs_rq, -se->avg.load_sum);
>  
>  	cfs_rq_util_change(cfs_rq, 0);
> +
> +	trace_pelt_cfs_rq(cfs_rq);
>  }
>  
>  /*
> @@ -5153,8 +5160,10 @@ static inline bool cpu_overutilized(int cpu)
>  
>  static inline void update_overutilized_status(struct rq *rq)
>  {
> -	if (!READ_ONCE(rq->rd->overutilized) && cpu_overutilized(rq->cpu))
> +	if (!READ_ONCE(rq->rd->overutilized) && cpu_overutilized(rq->cpu)) {
>  		WRITE_ONCE(rq->rd->overutilized, SG_OVERUTILIZED);
> +		trace_sched_overutilized(1);
> +	}
>  }
>  #else
>  static inline void update_overutilized_status(struct rq *rq) { }
> @@ -8516,8 +8525,11 @@ static inline void update_sd_lb_stats(struct lb_env *env, struct sd_lb_stats *sd
>  
>  		/* Update over-utilization (tipping point, U >= 0) indicator */
>  		WRITE_ONCE(rd->overutilized, sg_status & SG_OVERUTILIZED);
> +
> +		trace_sched_overutilized(!!(sg_status & SG_OVERUTILIZED));
>  	} else if (sg_status & SG_OVERUTILIZED) {
>  		WRITE_ONCE(env->dst_rq->rd->overutilized, SG_OVERUTILIZED);
> +		trace_sched_overutilized(1);
>  	}
>  }
>  
> @@ -10737,3 +10749,17 @@ __init void init_sched_fair_class(void)
>  #endif /* SMP */
>  
>  }
> +
> +char *sched_trace_cfs_rq_path(struct cfs_rq *cfs_rq, char *str, size_t len)
> +{
> +	cfs_rq_tg_path(cfs_rq, path, len);
> +	return str;
> +}
> +EXPORT_SYMBOL_GPL(sched_trace_cfs_rq_path);
> +
> +int sched_trace_cfs_rq_cpu(struct cfs_rq *cfs_rq)
> +{
> +	return cpu_of(rq_of(cfs_rq));
> +}
> +EXPORT_SYMBOL_GPL(sched_trace_cfs_rq_cpu);
> +
> diff --git a/kernel/sched/pelt.c b/kernel/sched/pelt.c
> index befce29bd882..ebca40ba71f3 100644
> --- a/kernel/sched/pelt.c
> +++ b/kernel/sched/pelt.c
> @@ -25,6 +25,7 @@
>   */
>  
>  #include <linux/sched.h>
> +#include <trace/events/sched.h>
>  #include "sched.h"
>  #include "pelt.h"
>  
> @@ -265,6 +266,7 @@ int __update_load_avg_blocked_se(u64 now, struct sched_entity *se)
>  {
>  	if (___update_load_sum(now, &se->avg, 0, 0, 0)) {
>  		___update_load_avg(&se->avg, se_weight(se), se_runnable(se));
> +		trace_pelt_se(se);
>  		return 1;
>  	}
>  
> @@ -278,6 +280,7 @@ int __update_load_avg_se(u64 now, struct cfs_rq *cfs_rq, struct sched_entity *se
>  
>  		___update_load_avg(&se->avg, se_weight(se), se_runnable(se));
>  		cfs_se_util_change(&se->avg);
> +		trace_pelt_se(se);
>  		return 1;
>  	}
>  
> @@ -292,6 +295,7 @@ int __update_load_avg_cfs_rq(u64 now, struct cfs_rq *cfs_rq)
>  				cfs_rq->curr != NULL)) {
>  
>  		___update_load_avg(&cfs_rq->avg, 1, 1);
> +		trace_pelt_cfs_rq(cfs_rq);
>  		return 1;
>  	}
>  
> @@ -317,6 +321,7 @@ int update_rt_rq_load_avg(u64 now, struct rq *rq, int running)
>  				running)) {
>  
>  		___update_load_avg(&rq->avg_rt, 1, 1);
> +//		sched_trace_pelt_rt_rq(rq);
>  		return 1;
>  	}
>  
> @@ -340,6 +345,7 @@ int update_dl_rq_load_avg(u64 now, struct rq *rq, int running)
>  				running)) {
>  
>  		___update_load_avg(&rq->avg_dl, 1, 1);
> +//		sched_trace_pelt_dl_rq(rq);
>  		return 1;
>  	}
>