On 2009-10-26, andrew bell <[email protected]> wrote: > I?ve gone back to the nc_master / slave tests and monitored > the throughput when connecting a PC to one of the boxes > running eCos. Initially everything looked fine until I insert > a switch between the PC and eCos box. > > With any switch between the PC / eCos box, there is poor > performance when doing an RX test (PC -> eCos box), which > shows lots of out of order delivery / delayed ACK / fast > rexmit, and the throughout graph looks like a saw tooth.
In my experience that's usually a sign of half/full duplex mismatch between one of the PHYs and the Ethernet controller to which it is attached. It could also be due to a mismatch between a PHY and the switch, but you've got to try pretty hard to make that happen. Can you try setting the switch ports to various different duplicities? Or try a half-duplex hub/switch instead of a full-duplex switch? > But hey, the PC?s running faster than the eCos box, so maybe > this is to be expected. Nope. -- Grant -- Before posting, please read the FAQ: http://ecos.sourceware.org/fom/ecos and search the list archive: http://ecos.sourceware.org/ml/ecos-discuss
