Using nextgen PCI Express switches to eliminate network I/O bottlenecks

By Steve Moore, PLX Technology
(02/06/08, 03:43:00 PM EST) -- Embedded.com

Controllers in today's network-connected embedded systems often are overwhelmed by the data streaming to and from the various I/O sources; it can be difficult for the system's root complex to absorb high-speed bursty traffic such as 10Gig Ethernet when it competes with very fast streaming data from sources such as InfiniBand and Fibre Channel (FC) storage elements.

For example, when a few bytes of Ethernet data get stuck behind large packets of FC data in the root complex, the latency that is introduced by this congestion will severely impact system response time and create bandwidth limitations (see Table 1 below).

Table 1. Ethernet latency bandwidth tradeoffs

The next generation of PCI Express (PCIe) switches have added many new features to mitigate the effects of having to process competing data protocols, thereby improving overall system performance.

Advanced new features such as Read Pacing, enhanced port configuration flexibility, dynamic buffer memory allocation, and the deployment of PCIe Gen2 signaling are reducing I/O bottlenecks, providing dramatic improvements in system performance in server and storage controllers.