Epiphany III to Zynq7010 DRAM bandwidth

[jamesh]

After a variety of tests (including with both fast.ldf and internal.ldf), I have observed that the memory bus bandwidth between the Parallella DRAM and the Epiphany III tops out at about 120 MB/s (regardless of the number of cores engaged in transfers...).

Basically this is equivalent to the throughput of Gigabit Ethernet, and it seems rather disappointing, given that the Epiphany chip itself is supposedly capable of 8 GB/s off-chip bandwidth (which would make it competitive with PCIe-based graphics cards...).

Has anyone been able to transfer between the Epiphany and DRAM at speeds greater than 120 MB/s? (I have mostly focused on testing the DMA, by the way.) Or is this the maximal throughput speed of that bus?

[FHuettig]

[jamesh]

[notzed]