nrf_usbd_common: Remove early DMA process handling (0efdff96) · Commits · Wenxi XU / zephyr

Early DMA process handling actually decreases performance in real world scenarios because real world scenarios tend to be CPU bound. Moreover the actual optimization is questionable because DMA semaphore can only be released after the respective endpoint end event is handled. Remove early DMA processing altogether and only check pending DMA at the end of interrupt handler. Signed-off-by:

Tomasz Moń <tomasz.mon@nordicsemi.no>

drivers/usb/common/nrf_usbd_common/nrf_usbd_common.c

+0 −18

Original line number	Diff line number	Diff line
		@@ -18,15 +18,6 @@
		#include <zephyr/logging/log.h>
		LOG_MODULE_REGISTER(nrf_usbd_common, CONFIG_NRF_USBD_COMMON_LOG_LEVEL);

		#ifndef NRF_USBD_COMMON_EARLY_DMA_PROCESS
		/* Try to process DMA request when endpoint transmission has been detected
		* and just after last EasyDMA has been processed.
		* It speeds up the transmission a little (about 10% measured)
		* with a cost of more CPU power used.
		*/
		#define NRF_USBD_COMMON_EARLY_DMA_PROCESS 1
		#endif

		#ifndef NRF_USBD_COMMON_STARTED_EV_ENABLE
		#define NRF_USBD_COMMON_STARTED_EV_ENABLE 0
		#endif
		@@ -988,11 +979,6 @@ static inline void nrf_usbd_epout_dma_handler(nrf_usbd_common_ep_t ep)
		} else {
		/* Nothing to do */
		}

		#if NRF_USBD_COMMON_EARLY_DMA_PROCESS
		/* Speed up */
		usbd_dmareq_process();
		#endif
		}

		/**
		@@ -1247,10 +1233,6 @@ static void ev_epdata_handler(void)

		(void)(usbd_ep_data_handler(ep, bitpos));
		}
		if (NRF_USBD_COMMON_EARLY_DMA_PROCESS) {
		/* Speed up */
		usbd_dmareq_process();
		}
		}

		/**

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