RE: [PATCH v3] sched: enable/disable TC OV at runtime

["Singh, Jasvinder" <jasvinder.singh@intel.com>]

> -----Original Message-----
> From: Danilewicz, MarcinX <marcinx.danilewicz@intel.com>
> Sent: Wednesday, April 27, 2022 10:24 AM
> To: dev@dpdk.org; Singh, Jasvinder <jasvinder.singh@intel.com>;
> Dumitrescu, Cristian <cristian.dumitrescu@intel.com>
> Cc: Ajmera, Megha <megha.ajmera@intel.com>
> Subject: [PATCH v3] sched: enable/disable TC OV at runtime
> 
> Added new API to enable or disable TC over subscription for best effort
> traffic class at subport level.
> Added changes after review and increased throughput.
> 
> By default TC OV is disabled.
> 
> Signed-off-by: Marcin Danilewicz <marcinx.danilewicz@intel.com>
> ---
>  lib/sched/rte_sched.c | 189 +++++++++++++++++++++++++++++++++++---
> ----
>  lib/sched/rte_sched.h |  18 ++++
>  lib/sched/version.map |   3 +
>  3 files changed, 178 insertions(+), 32 deletions(-)
> 
> diff --git a/lib/sched/rte_sched.c b/lib/sched/rte_sched.c index
> ec74bee939..6e7d81df46 100644
> --- a/lib/sched/rte_sched.c
> +++ b/lib/sched/rte_sched.c
> @@ -213,6 +213,9 @@ struct rte_sched_subport {
>  	uint8_t *bmp_array;
>  	struct rte_mbuf **queue_array;
>  	uint8_t memory[0] __rte_cache_aligned;
> +
> +	/* TC oversubscription activation */
> +	int is_tc_ov_enabled;
>  } __rte_cache_aligned;
> 
>  struct rte_sched_port {
> @@ -1165,6 +1168,45 @@ rte_sched_cman_config(struct rte_sched_port
> *port,  }  #endif
> 
> +int
> +rte_sched_subport_tc_ov_config(struct rte_sched_port *port,
> +	uint32_t subport_id,
> +	bool tc_ov_enable)
> +{
> +	struct rte_sched_subport *s;
> +	struct rte_sched_subport_profile *profile;
> +
> +	if (port == NULL) {
> +		RTE_LOG(ERR, SCHED,
> +			"%s: Incorrect value for parameter port\n",
> __func__);
> +		return -EINVAL;
> +	}
> +
> +	if (subport_id >= port->n_subports_per_port) {
> +		RTE_LOG(ERR, SCHED,
> +			"%s: Incorrect value for parameter subport id\n",
> __func__);
> +		return  -EINVAL;
> +	}
> +
> +	s = port->subports[subport_id];
> +	s->is_tc_ov_enabled = tc_ov_enable ? 1 : 0;
> +
> +	if (s->is_tc_ov_enabled) {
> +		/* TC oversubscription */
> +		s->tc_ov_wm_min = port->mtu;
> +		s->tc_ov_period_id = 0;
> +		s->tc_ov = 0;
> +		s->tc_ov_n = 0;
> +		s->tc_ov_rate = 0;
> +
> +		profile = port->subport_profiles + s->profile;
> +		s->tc_ov_wm_max = rte_sched_time_ms_to_bytes(profile-
> >tc_period,
> +				s->pipe_tc_be_rate_max);
> +		s->tc_ov_wm = s->tc_ov_wm_max;
> +	}
> +	return 0;
> +}
> +
>  int
>  rte_sched_subport_config(struct rte_sched_port *port,
>  	uint32_t subport_id,
> @@ -1254,6 +1296,9 @@ rte_sched_subport_config(struct rte_sched_port
> *port,
>  		s->n_pipe_profiles = params->n_pipe_profiles;
>  		s->n_max_pipe_profiles = params->n_max_pipe_profiles;
> 
> +		/* TC over-subscription is disabled by default */
> +		s->is_tc_ov_enabled = 0;
> +
>  #ifdef RTE_SCHED_CMAN
>  		if (params->cman_params != NULL) {
>  			s->cman_enabled = true;
> @@ -1316,13 +1361,6 @@ rte_sched_subport_config(struct rte_sched_port
> *port,
> 
>  		for (i = 0; i < RTE_SCHED_PORT_N_GRINDERS; i++)
>  			s->grinder_base_bmp_pos[i] =
> RTE_SCHED_PIPE_INVALID;
> -
> -		/* TC oversubscription */
> -		s->tc_ov_wm_min = port->mtu;
> -		s->tc_ov_period_id = 0;
> -		s->tc_ov = 0;
> -		s->tc_ov_n = 0;
> -		s->tc_ov_rate = 0;
>  	}
> 
>  	{
> @@ -1342,9 +1380,6 @@ rte_sched_subport_config(struct rte_sched_port
> *port,
>  			else
>  				profile->tc_credits_per_period[i] = 0;
> 
> -		s->tc_ov_wm_max = rte_sched_time_ms_to_bytes(profile-
> >tc_period,
> -							s-
> >pipe_tc_be_rate_max);
> -		s->tc_ov_wm = s->tc_ov_wm_max;
>  		s->profile = subport_profile_id;
> 
>  	}
> @@ -1417,17 +1452,20 @@ rte_sched_pipe_config(struct rte_sched_port
> *port,
>  		double pipe_tc_be_rate =
>  			(double) params-
> >tc_credits_per_period[RTE_SCHED_TRAFFIC_CLASS_BE]
>  			/ (double) params->tc_period;
> -		uint32_t tc_be_ov = s->tc_ov;
> 
> -		/* Unplug pipe from its subport */
> -		s->tc_ov_n -= params->tc_ov_weight;
> -		s->tc_ov_rate -= pipe_tc_be_rate;
> -		s->tc_ov = s->tc_ov_rate > subport_tc_be_rate;
> +		if (s->is_tc_ov_enabled) {
> +			uint32_t tc_be_ov = s->tc_ov;
> 
> -		if (s->tc_ov != tc_be_ov) {
> -			RTE_LOG(DEBUG, SCHED,
> -				"Subport %u Best-effort TC oversubscription
> is OFF (%.4lf >= %.4lf)\n",
> -				subport_id, subport_tc_be_rate, s-
> >tc_ov_rate);
> +			/* Unplug pipe from its subport */
> +			s->tc_ov_n -= params->tc_ov_weight;
> +			s->tc_ov_rate -= pipe_tc_be_rate;
> +			s->tc_ov = s->tc_ov_rate > subport_tc_be_rate;
> +
> +			if (s->tc_ov != tc_be_ov) {
> +				RTE_LOG(DEBUG, SCHED,
> +					"Subport %u Best-effort TC
> oversubscription is OFF (%.4lf >= %.4lf)\n",
> +					subport_id, subport_tc_be_rate, s-
> >tc_ov_rate);
> +			}
>  		}
> 
>  		/* Reset the pipe */
> @@ -1460,19 +1498,22 @@ rte_sched_pipe_config(struct rte_sched_port
> *port,
>  		double pipe_tc_be_rate =
>  			(double) params-
> >tc_credits_per_period[RTE_SCHED_TRAFFIC_CLASS_BE]
>  			/ (double) params->tc_period;
> -		uint32_t tc_be_ov = s->tc_ov;
> 
> -		s->tc_ov_n += params->tc_ov_weight;
> -		s->tc_ov_rate += pipe_tc_be_rate;
> -		s->tc_ov = s->tc_ov_rate > subport_tc_be_rate;
> +		if (s->is_tc_ov_enabled) {
> +			uint32_t tc_be_ov = s->tc_ov;
> +
> +			s->tc_ov_n += params->tc_ov_weight;
> +			s->tc_ov_rate += pipe_tc_be_rate;
> +			s->tc_ov = s->tc_ov_rate > subport_tc_be_rate;
> 
> -		if (s->tc_ov != tc_be_ov) {
> -			RTE_LOG(DEBUG, SCHED,
> -				"Subport %u Best effort TC oversubscription
> is ON (%.4lf < %.4lf)\n",
> -				subport_id, subport_tc_be_rate, s-
> >tc_ov_rate);
> +			if (s->tc_ov != tc_be_ov) {
> +				RTE_LOG(DEBUG, SCHED,
> +					"Subport %u Best effort TC
> oversubscription is ON (%.4lf < %.4lf)\n",
> +					subport_id, subport_tc_be_rate, s-
> >tc_ov_rate);
> +			}
> +			p->tc_ov_period_id = s->tc_ov_period_id;
> +			p->tc_ov_credits = s->tc_ov_wm;
>  		}
> -		p->tc_ov_period_id = s->tc_ov_period_id;
> -		p->tc_ov_credits = s->tc_ov_wm;
>  	}
> 
>  	return 0;
> @@ -2318,6 +2359,45 @@ grinder_credits_update(struct rte_sched_port
> *port,
>  	pipe->tb_credits = RTE_MIN(pipe->tb_credits, params->tb_size);
>  	pipe->tb_time += n_periods * params->tb_period;
> 
> +	/* Subport TCs */
> +	if (unlikely(port->time >= subport->tc_time)) {
> +		for (i = 0; i < RTE_SCHED_TRAFFIC_CLASSES_PER_PIPE; i++)
> +			subport->tc_credits[i] = sp-
> >tc_credits_per_period[i];
> +
> +		subport->tc_time = port->time + sp->tc_period;
> +	}
> +
> +	/* Pipe TCs */
> +	if (unlikely(port->time >= pipe->tc_time)) {
> +		for (i = 0; i < RTE_SCHED_TRAFFIC_CLASSES_PER_PIPE; i++)
> +			pipe->tc_credits[i] = params-
> >tc_credits_per_period[i];
> +		pipe->tc_time = port->time + params->tc_period;
> +	}
> +}
> +
> +static inline void
> +grinder_credits_update_with_tc_ov(struct rte_sched_port *port,
> +	struct rte_sched_subport *subport, uint32_t pos) {
> +	struct rte_sched_grinder *grinder = subport->grinder + pos;
> +	struct rte_sched_pipe *pipe = grinder->pipe;
> +	struct rte_sched_pipe_profile *params = grinder->pipe_params;
> +	struct rte_sched_subport_profile *sp = grinder->subport_params;
> +	uint64_t n_periods;
> +	uint32_t i;
> +
> +	/* Subport TB */
> +	n_periods = (port->time - subport->tb_time) / sp->tb_period;
> +	subport->tb_credits += n_periods * sp->tb_credits_per_period;
> +	subport->tb_credits = RTE_MIN(subport->tb_credits, sp->tb_size);
> +	subport->tb_time += n_periods * sp->tb_period;
> +
> +	/* Pipe TB */
> +	n_periods = (port->time - pipe->tb_time) / params->tb_period;
> +	pipe->tb_credits += n_periods * params->tb_credits_per_period;
> +	pipe->tb_credits = RTE_MIN(pipe->tb_credits, params->tb_size);
> +	pipe->tb_time += n_periods * params->tb_period;
> +
>  	/* Subport TCs */
>  	if (unlikely(port->time >= subport->tc_time)) {
>  		subport->tc_ov_wm =
> @@ -2348,6 +2428,39 @@ grinder_credits_update(struct rte_sched_port
> *port,  static inline int  grinder_credits_check(struct rte_sched_port *port,
>  	struct rte_sched_subport *subport, uint32_t pos)
> +{
> +	struct rte_sched_grinder *grinder = subport->grinder + pos;
> +	struct rte_sched_pipe *pipe = grinder->pipe;
> +	struct rte_mbuf *pkt = grinder->pkt;
> +	uint32_t tc_index = grinder->tc_index;
> +	uint64_t pkt_len = pkt->pkt_len + port->frame_overhead;
> +	uint64_t subport_tb_credits = subport->tb_credits;
> +	uint64_t subport_tc_credits = subport->tc_credits[tc_index];
> +	uint64_t pipe_tb_credits = pipe->tb_credits;
> +	uint64_t pipe_tc_credits = pipe->tc_credits[tc_index];
> +	int enough_credits;
> +
> +	/* Check pipe and subport credits */
> +	enough_credits = (pkt_len <= subport_tb_credits) &&
> +		(pkt_len <= subport_tc_credits) &&
> +		(pkt_len <= pipe_tb_credits) &&
> +		(pkt_len <= pipe_tc_credits);
> +
> +	if (!enough_credits)
> +		return 0;
> +
> +	/* Update pipe and subport credits */
> +	subport->tb_credits -= pkt_len;
> +	subport->tc_credits[tc_index] -= pkt_len;
> +	pipe->tb_credits -= pkt_len;
> +	pipe->tc_credits[tc_index] -= pkt_len;
> +
> +	return 1;
> +}
> +
> +static inline int
> +grinder_credits_check_with_tc_ov(struct rte_sched_port *port,
> +	struct rte_sched_subport *subport, uint32_t pos)
>  {
>  	struct rte_sched_grinder *grinder = subport->grinder + pos;
>  	struct rte_sched_pipe *pipe = grinder->pipe; @@ -2403,8 +2516,16
> @@ grinder_schedule(struct rte_sched_port *port,
>  	uint32_t pkt_len = pkt->pkt_len + port->frame_overhead;
>  	uint32_t be_tc_active;
> 
> -	if (!grinder_credits_check(port, subport, pos))
> -		return 0;
> +	switch (subport->is_tc_ov_enabled) {
> +	case 1:
> +		if (!grinder_credits_check_with_tc_ov(port, subport, pos))
> +			return 0;
> +		break;
> +	case 0:
> +		if (!grinder_credits_check(port, subport, pos))
> +			return 0;
> +		break;
> +	}
> 
>  	/* Advance port time */
>  	port->time += pkt_len;
> @@ -2770,7 +2891,11 @@ grinder_handle(struct rte_sched_port *port,
>  						subport->profile;
> 
>  		grinder_prefetch_tc_queue_arrays(subport, pos);
> -		grinder_credits_update(port, subport, pos);
> +
> +		if (unlikely(subport->is_tc_ov_enabled))
> +			grinder_credits_update_with_tc_ov(port, subport,
> pos);
> +		else
> +			grinder_credits_update(port, subport, pos);
> 
>  		grinder->state = e_GRINDER_PREFETCH_MBUF;
>  		return 0;
> diff --git a/lib/sched/rte_sched.h b/lib/sched/rte_sched.h index
> 5ece64e527..94febe1d94 100644
> --- a/lib/sched/rte_sched.h
> +++ b/lib/sched/rte_sched.h
> @@ -579,6 +579,24 @@ rte_sched_port_enqueue(struct rte_sched_port
> *port, struct rte_mbuf **pkts, uint  int  rte_sched_port_dequeue(struct
> rte_sched_port *port, struct rte_mbuf **pkts, uint32_t n_pkts);
> 
> +/**
> + * Hierarchical scheduler subport TC OV enable/disable config.
> + * Note that this function is safe to use at runtime
> + * to enable/disable TC OV for subport.
> + *
> + * @param port
> + *   Handle to port scheduler instance
> + * @param subport_id
> + *   Subport ID
> + * @param tc_ov_enable
> + *  Boolean flag to enable/disable TC OV
> + * @return
> + *   0 upon success, error code otherwise
> + */
> +__rte_experimental
> +int
> +rte_sched_subport_tc_ov_config(struct rte_sched_port *port, uint32_t
> +subport_id, bool tc_ov_enable);
> +
>  #ifdef __cplusplus
>  }
>  #endif
> diff --git a/lib/sched/version.map b/lib/sched/version.map index
> d22c07fc9f..c6e994d8df 100644
> --- a/lib/sched/version.map
> +++ b/lib/sched/version.map
> @@ -34,4 +34,7 @@ EXPERIMENTAL {
>  	# added in 21.11
>  	rte_pie_rt_data_init;
>  	rte_pie_config_init;
> +
> +	# added in 22.03
> +	rte_sched_subport_tc_ov_config;
>  };
> --
> 2.25.1


Hi Marcin,

I don't see any note on the changes made in this version with respect to previous versions.  Can you include them in future version?  Also, I had some comments on the first version of this patch, I don't see any response.