Re: [dpdk-dev] [PATCH v2 4/6] examples/ioat: port application to dmadev APIs

[Kevin Laatz <kevin.laatz@intel.com>]

On 24/09/2021 05:00, fengchengwen wrote:
> On 2021/9/18 0:41, Kevin Laatz wrote:
>> The dmadev library abstraction allows applications to use the same APIs for
>> all DMA device drivers in DPDK. This patch updates the ioatfwd application
>> to make use of the new dmadev APIs, in turn making it a generic application
>> which can be used with any of the DMA device drivers.
>>
>> Signed-off-by: Kevin Laatz <kevin.laatz@intel.com>
>>
>> ---
>> v2:
>>    - dmadev api name updates following rebase
>>    - use rte_config macro for max devs
>>    - use PRIu64 for printing stats
>> ---
>>   examples/ioat/ioatfwd.c   | 239 ++++++++++++++++----------------------
>>   examples/ioat/meson.build |   8 +-
>>   2 files changed, 105 insertions(+), 142 deletions(-)
>>
> [snip]
>
>>   
>>   typedef enum copy_mode_t {
>> @@ -95,6 +94,16 @@ static copy_mode_t copy_mode = COPY_MODE_IOAT_NUM;
>>    */
>>   static unsigned short ring_size = 2048;
>>   
>> +/* global mbuf arrays for tracking DMA bufs */
>> +#define MBUF_RING_SIZE	1024
>> +#define MBUF_RING_MASK	(MBUF_RING_SIZE - 1)
>> +struct dma_bufs {
>> +	struct rte_mbuf *bufs[MBUF_RING_SIZE];
>> +	struct rte_mbuf *copies[MBUF_RING_SIZE];
>> +	uint16_t sent;
>> +};
> The dma_bufs size only hold 1024 address info, and the dmadev virtual channel ring size is 2048 default,
> If the DMA cannot be moved in time, may exist overlay in dma_bufs in dma_dequeue() API.

Will match the dmadev lib default in v3.


>
>> +static struct dma_bufs dma_bufs[RTE_DMADEV_DEFAULT_MAX_DEVS];
>> +
>>   /* global transmission config */
>>   struct rxtx_transmission_config cfg;
> [snip]
>
>>   }
>>   /* >8 End of configuration of device. */
>>   
>> @@ -820,18 +789,16 @@ assign_rawdevs(void)
>>   
>>   	for (i = 0; i < cfg.nb_ports; i++) {
>>   		for (j = 0; j < cfg.ports[i].nb_queues; j++) {
>> -			struct rte_rawdev_info rdev_info = { 0 };
>> +			struct rte_dma_info dmadev_info = { 0 };
>>   
>>   			do {
>> -				if (rdev_id == rte_rawdev_count())
>> +				if (rdev_id == rte_dma_count_avail())
>>   					goto end;
>> -				rte_rawdev_info_get(rdev_id++, &rdev_info, 0);
>> -			} while (rdev_info.driver_name == NULL ||
>> -					strcmp(rdev_info.driver_name,
>> -						IOAT_PMD_RAWDEV_NAME_STR) != 0);
>> +				rte_dma_info_get(rdev_id++, &dmadev_info);
>> +			} while (!rte_dma_is_valid(rdev_id));
>>   
>> -			cfg.ports[i].ioat_ids[j] = rdev_id - 1;
>> -			configure_rawdev_queue(cfg.ports[i].ioat_ids[j]);
>> +			cfg.ports[i].dmadev_ids[j] = rdev_id - 1;
>> +			configure_rawdev_queue(cfg.ports[i].dmadev_ids[j]);
> Tests show that if there are four dmadevs, only three dmadevs can be allocated here.
>
> 1st malloc: rdev_id=0, assign successful, and the dmadev_id=0, rdev_id=1
> 2st malloc: rdev_id=1, assign successful, and the dmadev_id=1, rdev_id=2
> 3st malloc: rdev_id=2, assign successful, and the dmadev_id=2, rdev_id=3
> 4st malloc: rdev_id=3, assign failed, because rte_dma_info_get(rdev_id++,...), the rdev_id is 4 and it's not a valid id.
>
> Recommended use rte_dma_next_dev() which Bruce introduced.

Ack, will use rte_dma_next_dev() in v3.

Thanks!


>>   			++nb_rawdev;
>>   		}
>>   	}
>> @@ -840,7 +807,7 @@ assign_rawdevs(void)
>>   		rte_exit(EXIT_FAILURE,
>>   			"Not enough IOAT rawdevs (%u) for all queues (%u).\n",
>>   			nb_rawdev, cfg.nb_ports * cfg.ports[0].nb_queues);
>> -	RTE_LOG(INFO, IOAT, "Number of used rawdevs: %u.\n", nb_rawdev);
>> +	RTE_LOG(INFO, DMA, "Number of used rawdevs: %u.\n", nb_rawdev);
>>   }
>>   /* >8 End of using IOAT rawdev API functions. */
>>   
> [snip]
>