Re: [dpdk-dev] [PATCH 1/2] librte_sched: add post-init pipe profile api

["Dumitrescu, Cristian" <cristian.dumitrescu@intel.com>]

Hi Jasvinder,

Looks good, a few things to fix below:

> -----Original Message-----
> From: Singh, Jasvinder
> Sent: Friday, March 9, 2018 6:41 PM
> To: dev@dpdk.org
> Cc: Dumitrescu, Cristian <cristian.dumitrescu@intel.com>
> Subject: [PATCH 1/2] librte_sched: add post-init pipe profile api
> 
> Add new API function to add more pipe configuration profiles
> post initialization to the set of exisitng profiles specified during
> the creation of scheduler port.
> 
> This API removes the current limitation that forces the user
> to define the full set of pipe profiles as the part of port parameters
> while port is being created.
> 
> Signed-off-by: Jasvinder Singh <jasvinder.singh@intel.com>
> ---
>  lib/librte_sched/rte_sched.c           | 141
> +++++++++++++++++++++++++++++++++
>  lib/librte_sched/rte_sched.h           |  17 ++++
>  lib/librte_sched/rte_sched_version.map |   6 ++
>  3 files changed, 164 insertions(+)
> 
> diff --git a/lib/librte_sched/rte_sched.c b/lib/librte_sched/rte_sched.c
> index 634486c..43728ec 100644
> --- a/lib/librte_sched/rte_sched.c
> +++ b/lib/librte_sched/rte_sched.c
> @@ -932,6 +932,147 @@ rte_sched_pipe_config(struct rte_sched_port
> *port,
>  	return 0;
>  }
> 
> +static void
> +rte_sched_pipe_profile_get(struct rte_sched_port *port,
> +	struct rte_sched_pipe_params *params,
> +	struct rte_sched_pipe_profile *p)
> +{
> +	uint32_t i;
> +
> +	/* Token Bucket */
> +	if (params->tb_rate == port->rate) {
> +		p->tb_credits_per_period = 1;
> +		p->tb_period = 1;
> +	} else {
> +		double tb_rate = (double) params->tb_rate
> +				/ (double) port->rate;
> +		double d = RTE_SCHED_TB_RATE_CONFIG_ERR;
> +
> +		rte_approx(tb_rate, d,
> +				   &p->tb_credits_per_period, &p-
> >tb_period);
> +	}
> +
> +	p->tb_size = params->tb_size;
> +
> +	/* Traffic Classes */
> +	p->tc_period = rte_sched_time_ms_to_bytes(params->tc_period,
> +		port->rate);
> +
> +	for (i = 0; i < RTE_SCHED_TRAFFIC_CLASSES_PER_PIPE; i++)
> +		p->tc_credits_per_period[i]
> +			= rte_sched_time_ms_to_bytes(params->tc_period,
> +				params->tc_rate[i]);
> +
> +#ifdef RTE_SCHED_SUBPORT_TC_OV
> +	p->tc_ov_weight = params->tc_ov_weight;
> +#endif
> +
> +	/* WRR */
> +	for (i = 0; i < RTE_SCHED_TRAFFIC_CLASSES_PER_PIPE; i++) {
> +		uint32_t
> wrr_cost[RTE_SCHED_QUEUES_PER_TRAFFIC_CLASS];
> +		uint32_t lcd, lcd1, lcd2;
> +		uint32_t qindex;
> +
> +		qindex = i * RTE_SCHED_QUEUES_PER_TRAFFIC_CLASS;
> +
> +		wrr_cost[0] = params->wrr_weights[qindex];
> +		wrr_cost[1] = params->wrr_weights[qindex + 1];
> +		wrr_cost[2] = params->wrr_weights[qindex + 2];
> +		wrr_cost[3] = params->wrr_weights[qindex + 3];
> +
> +		lcd1 = rte_get_lcd(wrr_cost[0], wrr_cost[1]);
> +		lcd2 = rte_get_lcd(wrr_cost[2], wrr_cost[3]);
> +		lcd = rte_get_lcd(lcd1, lcd2);
> +
> +		wrr_cost[0] = lcd / wrr_cost[0];
> +		wrr_cost[1] = lcd / wrr_cost[1];
> +		wrr_cost[2] = lcd / wrr_cost[2];
> +		wrr_cost[3] = lcd / wrr_cost[3];
> +
> +		p->wrr_cost[qindex] = (uint8_t) wrr_cost[0];
> +		p->wrr_cost[qindex + 1] = (uint8_t) wrr_cost[1];
> +		p->wrr_cost[qindex + 2] = (uint8_t) wrr_cost[2];
> +		p->wrr_cost[qindex + 3] = (uint8_t) wrr_cost[3];
> +	}
> +}

I suggest a slightly different name: convert instead of get; I encourage using dst and src as the names for the args, as it makes the code easier to follow.

Please call this function as part of rte_sched_port_config_pipe_profile_table() to avoid duplicating this code.

> +
> +int
> +rte_sched_pipe_profile_add(struct rte_sched_port *port,
> +	struct rte_sched_pipe_params *params,
> +	int32_t *profile_id)
> +{
> +	struct rte_sched_pipe_profile pp;
> +	uint32_t i;
> +
> +	/* Port */
> +	if (port == NULL)
> +		return -1;
> +
> +	/* Pipe parameters */
> +	if (params == NULL)
> +		return -2;
> +
> +	/* TB rate: non-zero, not greater than port rate */
> +	if (params->tb_rate == 0 ||
> +		params->tb_rate > port->rate)
> +		return -3;
> +
> +	/* TB size: non-zero */
> +	if (params->tb_size == 0)
> +		return -4;
> +
> +	/* TC rate: non-zero, less than pipe rate */
> +	for (i = 0; i < RTE_SCHED_TRAFFIC_CLASSES_PER_PIPE; i++) {
> +		if (params->tc_rate[i] == 0 ||
> +			params->tc_rate[i] > params->tb_rate)
> +			return -5;
> +	}
> +
> +	/* TC period: non-zero */
> +	if (params->tc_period == 0)
> +		return -6;
> +
> +#ifdef RTE_SCHED_SUBPORT_TC_OV
> +	/* TC3 oversubscription weight: non-zero */
> +	if (params->tc_ov_weight == 0)
> +		return -7;
> +#endif
> +
> +	/* Queue WRR weights: non-zero */
> +	for (i = 0; i < RTE_SCHED_QUEUES_PER_PIPE; i++) {
> +		if (params->wrr_weights[i] == 0)
> +			return -8;
> +	}
> +

Please put this checks into a new pipe_profile_check() function and call it from rte_sched_port_check_params() to avoid code duplication.

> +	/* Pipe profiles not exceeds the max limit */
> +	if (port->n_pipe_profiles >= RTE_SCHED_PIPE_PROFILES_PER_PORT)
> +		return -9;
> +
> +	memset(&pp, 0, sizeof(struct rte_sched_pipe_profile));

There is no need to use a temporary local copy, you can work straight on top of the real &port->pipe_profiles[port->n_pipe_profiles], as long as you only increment port->n_pipe_profiles when you are completely sure everything is OK.

> +	rte_sched_pipe_profile_get(port, params, &pp);
> +
> +	/* Pipe profile not exists */
> +	for (i = 0; i < port->n_pipe_profiles; i++) {
> +		if (memcmp(port->pipe_profiles + i, &pp, sizeof(pp)) == 0)
> +			return -10;
> +	}
> +
> +	/* Set port params */
> +	memcpy(port->pipe_profiles + port->n_pipe_profiles, &pp,
> sizeof(pp));

Based on the above comment of pp temp not needed, this memcpy can be eliminated.

> +
> +	uint32_t pipe_tc3_rate = params->tc_rate[3];
> +
> +	if (port->pipe_tc3_rate_max < pipe_tc3_rate)
> +		port->pipe_tc3_rate_max = pipe_tc3_rate;
> +
> +	*profile_id = port->n_pipe_profiles;
> +	port->n_pipe_profiles += 1;

Maybe move this port->n_pipe_profiles++ earlier, just after we performed the "pipe profile exists" check, easier to read the code. I would also put a comment similar to "pipe profile commit" for this.

> +
> +	rte_sched_port_log_pipe_profile(port, *profile_id);
> +
> +	return 0;
> +}
> +
>  void
>  rte_sched_port_pkt_write(struct rte_mbuf *pkt,
>  			 uint32_t subport, uint32_t pipe, uint32_t
> traffic_class,
> diff --git a/lib/librte_sched/rte_sched.h b/lib/librte_sched/rte_sched.h
> index 5d2a688..7edccbe 100644
> --- a/lib/librte_sched/rte_sched.h
> +++ b/lib/librte_sched/rte_sched.h
> @@ -271,6 +271,23 @@ rte_sched_pipe_config(struct rte_sched_port
> *port,
>  	int32_t pipe_profile);
> 
>  /**
> + * Hierarchical scheduler pipe profile add
> + *
> + * @param port
> + *   Handle to port scheduler instance
> + * @param params
> + *   Pipe configuration parameters
> + * @param pipe_profile_id
> + *   Set to valid profile id when profile is added successfully.
> + * @return
> + *   0 upon success, error code otherwise
> + */
> +int
> +rte_sched_pipe_profile_add(struct rte_sched_port *port,
> +	struct rte_sched_pipe_params *params,
> +	int32_t *pipe_profile_id);

Why is pipe_profile_id of type int32_t instead of uint32_t? The port-> n_pipe_profiles is uint32_t.

> +
> +/**
>   * Hierarchical scheduler memory footprint size per port
>   *
>   * @param params
> diff --git a/lib/librte_sched/rte_sched_version.map
> b/lib/librte_sched/rte_sched_version.map
> index 3aa159a..b709cf8 100644
> --- a/lib/librte_sched/rte_sched_version.map
> +++ b/lib/librte_sched/rte_sched_version.map
> @@ -29,3 +29,9 @@ DPDK_2.1 {
>  	rte_sched_port_pkt_read_color;
> 
>  } DPDK_2.0;
> +
> +DPDK_18.05 {
> +	global:
> +
> +	rte_sched_pipe_profile_add;
> +} DPDK_2.1;
> --

We probably need to increment LIBABIVER in the Makefile and bump the .so number in release notes.

> 2.9.3


Thanks very much!

Regards,
Cristian