Hi,
Thanks for adding the app. Few comments inline. Please check.
Thanks,
Anoob
> -----Original Message-----
> From: Cheng Jiang <cheng1.ji...@intel.com>
> Sent: Thursday, June 8, 2023 2:14 PM
> To: tho...@monjalon.net; bruce.richard...@intel.com;
> m...@smartsharesystems.com; chenbo....@intel.com
> Cc: dev@dpdk.org; jiayu...@intel.com; xuan.d...@intel.com;
> wenwux...@intel.com; yuanx.w...@intel.com; xingguang...@intel.com;
> Cheng Jiang <cheng1.ji...@intel.com>
> Subject: [EXT] [PATCH v5] app/dma-perf: introduce dma-perf application
>
> External Email
>
> ----------------------------------------------------------------------
> There are many high-performance DMA devices supported in DPDK now,
> and these DMA devices can also be integrated into other modules of DPDK as
> accelerators, such as Vhost. Before integrating DMA into applications,
> developers need to know the performance of these DMA devices in various
> scenarios and the performance of CPUs in the same scenario, such as
> different buffer lengths. Only in this way can we know the target
> performance of the application accelerated by using them. This patch
> introduces a high-performance testing tool, which supports comparing the
> performance of CPU and DMA in different scenarios automatically with a pre-
> set config file. Memory Copy performance test are supported for now.
>
> Signed-off-by: Cheng Jiang <cheng1.ji...@intel.com>
> Signed-off-by: Jiayu Hu <jiayu...@intel.com>
> Signed-off-by: Yuan Wang <yuanx.w...@intel.com>
> Acked-by: Morten Brørup <m...@smartsharesystems.com>
> Acked-by: Chenbo Xia <chenbo....@intel.com>
> ---
> v5:
> fixed some LONG_LINE warnings;
> v4:
> fixed inaccuracy of the memory footprint display;
> v3:
> fixed some typos;
> v2:
> added lcore/dmadev designation;
> added error case process;
> removed worker_threads parameter from config.ini;
> improved the logs;
> improved config file;
>
> app/meson.build | 1 +
> app/test-dma-perf/benchmark.c | 472 ++++++++++++++++++++++++++++
> app/test-dma-perf/config.ini | 59 ++++
> app/test-dma-perf/main.c | 569
> ++++++++++++++++++++++++++++++++++
> app/test-dma-perf/main.h | 69 +++++
> app/test-dma-perf/meson.build | 17 +
> 6 files changed, 1187 insertions(+)
> create mode 100644 app/test-dma-perf/benchmark.c create mode 100644
> app/test-dma-perf/config.ini create mode 100644 app/test-dma-
> perf/main.c create mode 100644 app/test-dma-perf/main.h create mode
> 100644 app/test-dma-perf/meson.build
>
<snip>
> +
> +/* Configuration of device. */
> +static void
> +configure_dmadev_queue(uint32_t dev_id, uint32_t ring_size) {
> + uint16_t vchan = 0;
> + struct rte_dma_info info;
> + struct rte_dma_conf dev_config = { .nb_vchans = 1 };
[Anoob] Is it possible to use more vchans? The code launches as many threads as
the number of dma devices. Instead it should be total number of vchans.
> + struct rte_dma_vchan_conf qconf = {
> + .direction = RTE_DMA_DIR_MEM_TO_MEM,
> + .nb_desc = ring_size
> + };
> +
> + if (rte_dma_configure(dev_id, &dev_config) != 0)
> + rte_exit(EXIT_FAILURE, "Error with dma configure.\n");
> +
> + if (rte_dma_vchan_setup(dev_id, vchan, &qconf) != 0)
> + rte_exit(EXIT_FAILURE, "Error with queue configuration.\n");
> +
> + rte_dma_info_get(dev_id, &info);
> + if (info.nb_vchans != 1)
> + rte_exit(EXIT_FAILURE, "Error, no configured queues
> reported on device id. %u\n",
> + dev_id);
> +
> + if (rte_dma_start(dev_id) != 0)
> + rte_exit(EXIT_FAILURE, "Error with dma start.\n"); }
> +
> +
<snip>
> +static inline int
> +do_dma_mem_copy(void *p)
> +{
> + uint16_t *para_idx = (uint16_t *)p;
> + volatile struct lcore_params *para = worker_params[*para_idx];
> + volatile struct worker_info *worker_info = &(para->worker_info);
> + uint16_t dev_id = para->dev_id;
> + uint32_t nr_buf = para->nr_buf;
> + uint16_t kick_batch = para->kick_batch;
[Anoob] Some of these variables can be made const. Since this is fast path,
might be beneficial doing that way.
> + uint32_t buf_size = para->buf_size;
> + struct rte_mbuf **srcs = para->srcs;
> + struct rte_mbuf **dsts = para->dsts;
> + int64_t async_cnt = 0;
> + int nr_cpl = 0;
> + uint32_t i;
> + uint32_t poll_cnt = 0;
> +
> + worker_info->stop_flag = false;
> + worker_info->ready_flag = true;
> +
> + while (!worker_info->start_flag)
> + ;
> +
> + while (1) {
> + for (i = 0; i < nr_buf; i++) {
> + if (unlikely(rte_dma_copy(dev_id,
> + 0,
> + rte_pktmbuf_iova(srcs[i]),
> + rte_pktmbuf_iova(dsts[i]),
> + buf_size,
> + 0) < 0)) {
> + rte_dma_submit(dev_id, 0);
> + while (rte_dma_burst_capacity(dev_id, 0) ==
> 0) {
> + nr_cpl = rte_dma_completed(dev_id,
> 0, MAX_DMA_CPL_NB,
> + NULL, NULL);
> + async_cnt -= nr_cpl;
> + worker_info->total_cpl += nr_cpl;
> + }
> + if (rte_dma_copy(dev_id,
> + 0,
> + rte_pktmbuf_iova(srcs[i]),
> + rte_pktmbuf_iova(dsts[i]),
> + buf_size,
> + 0) < 0) {
> + printf("enqueue fail again at %u\n",
> i);
> + printf("space:%d\n",
> rte_dma_burst_capacity(dev_id, 0));
> + rte_exit(EXIT_FAILURE, "DMA
> enqueue failed\n");
> + }
[Anoob] Only if the API returns -ENOSPC we should retry submitting, right?
Other errors should be treated as fatal errors.
Do we need to use rte_dma_burst_capacity() API?
Can't we try something like,
dma_copy:
ret = rte_dma_copy(dev_id, 0, rte_pktmbuf_iova(srcs[i]),
rte_pktmbuf_iova(dsts[i]), buf_size, 0);
if (unlikely (ret < 0) {
if (ret == -ENOSPC) {
rte_dma_submit(dev_id, 0);
/* DMA completed & other handling */
goto dma_copy;
} else {
/* Error exit */
}
}
> + }
> + async_cnt++;
> +
> + if ((async_cnt % kick_batch) == 0) {
> + rte_dma_submit(dev_id, 0);
> + /* add a poll to avoid ring full */
> + nr_cpl = rte_dma_completed(dev_id, 0,
> MAX_DMA_CPL_NB, NULL, NULL);
> + async_cnt -= nr_cpl;
> + worker_info->total_cpl += nr_cpl;
[Anoob] Above code can be made as a static inline function so that in cases
rte_dma_copy returns -ENOSPC, same static inline can be called.
<snip>
