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au-ts / sddf

A collection of interfaces, libraries and tools for writing device drivers for seL4 that allow accessing devices securely and with low overhead.
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Remove string.h dependence from the networking copy component #179

Closed Courtney3141 closed 1 month ago

Courtney3141 commented 1 month ago

This PR updates the network copy component to not depend on string.h and instead use sddf/util/string.h. This allows the network components to be compiled without built in string functions.

Surprisingly, utilising the byte by byte sddf_memcpy does not seem to negatively impact performance. I took two samples on the IMX8mm and odroidc4:

Requested_Throughput,Receive_Throughput,Send_Throughput,Packet_Size,Minimum_RTT,Average_RTT,Maximum_RTT,Stdev_RTT,Median_RTT,Idle_Cycles,Total_Cycles

IMX8MM -sddf_memcpy: 1000000000,957035645,999995450,1472,1329,1516,1944,97.95,1471,6230124072,23058230899 (0.7298) IMX8MM -built in memcpy: 1000000000,957447712,999994417,1472,1340,1519,1959,94.60,1475,0,6262811899,23007070662 (0.7277) odroidc4 -sddf_memcpy: 600000000,594346605,600002066,1472,562,910,1938,137.83,886,0,7298553638,23758305220 (0.6927) odroidc4 -built in memcpy: 600000000,595561379,600000631,1472,575,911,1467,136.09,888,0,7213734934,24867576841 (0.7099)

Regardless, it is future work to update sDDF string definitions to be more efficient.