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LF-2(8) Number of transmit descriptors. For DMA-based devices, this value is utilized by the device driver during initialization in order to allocate a fixed-size pool of transmit descriptors to be used by the device. For best performance, the number of transmit descriptors should be equal to the number of small, plus the number of large transmit buffers configured for the device. Non DMA based devices may configure this value to zero.
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Window Sizes
Receive and transmit queue size must be properly configured to optimize performance. It represents the number of bytes that can be queued by one socket. It's important that all socket are not able to queue more data than what the device can hold in its buffers. The size should be also a multiple of the maximum segment size (MSS) to optimize performance. UDP MSS is 1470 and TCP MSS is 1460.
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RX and TX queue size can be reduce at run time using socket option API (NetTCP_ConnCfgRxWinSize & and NetTCP_ConnCfgTxWinSize).
the following listing shows a calculation example:
Number of TCP connection : 2
Number of UDP connection : 0
Number of RX large buffer : 10
Number of TX Large buffer : 6
Number of TX small buffer : 2
Size of RX large buffer : 1518
Size of TX large buffer : 1518
Size of TX small buffer : 60
TCP MSS RX = 1460
TCP MSS TX large buffer = 1460
TCP MSS TX small buffer = 0
Maximum receive window = (10 * 1460) = 14600 bytes
Maximum transmit window = (6 * 1460) + (2 * 0) = 8760 bytes
RX window size per socket = (14600 / 2) = 7300 bytes
TX window size per socket = (8760 / 2) = 4380 bytes...
Reducing the Number of Transitory Errors (NET_ERR_TX)
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