Performance improvement of PCI Express adapter cards by adjusting the location of DMA functions

The PCIe (PCI Express) bus has long played a key role in interconnecting devices inside a system. In addition, advances in PCIe technology have made it possible to connect between servers using the PCIe bus. In this study, we've tried to improve the performance of our PCIe adapter cards for expanding the PCIe bus and connecting servers. Especially, we've looked for ways to make the most of the DMA capabilities offered by the PCIe switch chips mounted on our adapter cards. Our experimental results show that the dual ports method using multiple DMAs in each adapter card simultaneously, improves the performance up to 1.7 times compared to using a single port.