[PATCH v2 2/2] ring: add ring info telemetry cmd

[Konstantin Ananyev]

> This patch supports dump of the info of ring by its name.
> An example using this command is shown below:
> 
> --> /ring/info,MP_mb_pool_0
> {
>    "/ring/info": {
>      "name": "MP_mb_pool_0",
>      "socket": 0,
>      "flags": 0,
>      "producer_type": "MP",
>      "consumer_type": "MC",
>      "size": 262144,
>      "mask": 262143,
>      "capacity": 262143,
>      "used_count": 147173,
>      "consumer_tail": 8283,
>      "consumer_head": 8283,
>      "producer_tail": 155456,
>      "producer_head": 155456,
>      "mz_name": "RG_MP_mb_pool_0",
>      "mz_len": 2097920,
>      "mz_hugepage_sz": 1073741824,
>      "mz_socket_id": 0,
>      "mz_flags": 0
>    }
> }
> 
> Signed-off-by: Jie Hai <haijie1 at huawei.com>
> ---
>   lib/ring/rte_ring.c | 88 +++++++++++++++++++++++++++++++++++++++++++++
>   1 file changed, 88 insertions(+)
> 
> diff --git a/lib/ring/rte_ring.c b/lib/ring/rte_ring.c
> index bb1dafd4d1ca..82f3d6a6cd60 100644
> --- a/lib/ring/rte_ring.c
> +++ b/lib/ring/rte_ring.c
> @@ -45,6 +45,9 @@ EAL_REGISTER_TAILQ(rte_ring_tailq)
>   /* by default set head/tail distance as 1/8 of ring capacity */
>   #define HTD_MAX_DEF	8
>   
> +/* size of name of producer/consumer synchronization modes */
> +#define SYNC_MODE_NAME_SZ	16
> +
>   /* return the size of memory occupied by a ring */
>   ssize_t
>   rte_ring_get_memsize_elem(unsigned int esize, unsigned int count)
> @@ -454,8 +457,93 @@ ring_handle_list(const char *cmd __rte_unused,
>   	return 0;
>   }
>   
> +static void
> +ring_get_sync_name_by_type(struct rte_ring *r, char *prod, char *cons)
> +{
> +	switch (r->prod.sync_type) {
> +	case RTE_RING_SYNC_MT:
> +		strcpy(prod, "MP");
> +		break;
> +	case RTE_RING_SYNC_ST:
> +		strcpy(prod, "SP");
> +		break;
> +	case RTE_RING_SYNC_MT_RTS:
> +		strcpy(prod, "MP_RTS");
> +		break;
> +	case RTE_RING_SYNC_MT_HTS:
> +		strcpy(prod, "MP_HTS");
> +		break;
> +	default:
> +		strcpy(prod, "Unknown");
> +	}

It is probably not the best option to blindly copy strings somewhere.
I think it would be better to introduce function like that:
static const char *
ring_prod_sync_type_to_name(enum rte_ring_sync_type type)
{
	switch(type) {
		case RTE_RING_SYNC_MT: return "MP";
		case RTE_RING_SYNC_ST: return "SP";
		...
	}
	return "Unknown";
}

Same for _cons_ type and use them accordingly.


> +
> +	switch (r->cons.sync_type) {
> +	case RTE_RING_SYNC_MT:
> +		strcpy(cons, "MC");
> +		break;
> +	case RTE_RING_SYNC_ST:
> +		strcpy(cons, "SC");
> +		break;
> +	case RTE_RING_SYNC_MT_RTS:
> +		strcpy(cons, "MC_RTS");
> +		break;
> +	case RTE_RING_SYNC_MT_HTS:
> +		strcpy(cons, "MC_HTS");
> +		break;
> +	default:
> +		strcpy(cons, "Unknown");
> +	}
> +}




> +
> +static int
> +ring_handle_info(const char *cmd __rte_unused, const char *params,
> +		struct rte_tel_data *d)
> +{
> +	char prod_type[SYNC_MODE_NAME_SZ];
> +	char cons_type[SYNC_MODE_NAME_SZ];
> +	const struct rte_memzone *mz;
> +	char name[RTE_RING_NAMESIZE];
> +	struct rte_ring *r;
> +
> +	if (params == NULL || strlen(params) == 0 ||
> +		strlen(params) >= RTE_RING_NAMESIZE)
> +		return -EINVAL;
> +
> +	strlcpy(name, params, RTE_RING_NAMESIZE);

That copy looks absolutely redundant, you can do just
rte_ring_lookup(params) instead.

> +	r = rte_ring_lookup(name);
> +	if (r == NULL)
> +		return -EINVAL;
> +
> +	rte_tel_data_start_dict(d);
> +	rte_tel_data_add_dict_string(d, "name", r->name);


Do I get it right that it could be executed from specific telemetry thread?
If so, we probably shouldn't release rte_mcfg_tailq_read_lock while
accessing ring data.


> +	rte_tel_data_add_dict_int(d, "socket", r->memzone->socket_id);

You do print it below, when printing memzone related data.

> +	rte_tel_data_add_dict_int(d, "flags", r->flags);
> +	ring_get_sync_name_by_type(r, prod_type, cons_type);
> +	rte_tel_data_add_dict_string(d, "producer_type", prod_type);
> +	rte_tel_data_add_dict_string(d, "consumer_type", cons_type);
> +	rte_tel_data_add_dict_u64(d, "size", r->size);
> +	rte_tel_data_add_dict_u64(d, "mask", r->mask);
> +	rte_tel_data_add_dict_u64(d, "capacity", r->capacity);
> +	rte_tel_data_add_dict_u64(d, "used_count", rte_ring_count(r));
> +	rte_tel_data_add_dict_u64(d, "consumer_tail", r->cons.tail);
> +	rte_tel_data_add_dict_u64(d, "consumer_head", r->cons.head);
> +	rte_tel_data_add_dict_u64(d, "producer_tail", r->prod.tail);
> +	rte_tel_data_add_dict_u64(d, "producer_head", r->prod.head);
> +
> +	mz = r->memzone;``

Would it make sense to check that mz != NULL here?
I know that it shouldn't be NULL for valid ring created by 
rte_ring_create(), but still probably no harm.

> +	rte_tel_data_add_dict_string(d, "mz_name", mz->name);
> +	rte_tel_data_add_dict_int(d, "mz_len", mz->len);
> +	rte_tel_data_add_dict_int(d, "mz_hugepage_sz", mz->hugepage_sz);
> +	rte_tel_data_add_dict_int(d, "mz_socket_id", mz->socket_id);
> +	rte_tel_data_add_dict_int(d, "mz_flags", mz->flags);
> +
> +	return 0;
> +}
> +
>   RTE_INIT(ring_init_telemetry)
>   {
>   	rte_telemetry_register_cmd("/ring/list", ring_handle_list,
>   		"Returns list of available ring. Takes no parameters");
> +	rte_telemetry_register_cmd("/ring/info", ring_handle_info,
> +		"Returns ring info. Parameters: ring_name.");
>   }