Hi Guys, I'm currently writing my first bit of Linux kernel code so be gentle. It's a driver for TI CC2420 802.15.4 radio and I'm observing strange behavior. I am currently testing just by transferring a ~300kb file over HTTP between two of these devices.
The strange thing is, when ever you start the transfer it starts humming along at 5k/s which is not far off what I'd expect these devices to achieve, then at some random point along the transfer or sometimes not at all... it suddenly drops fairly deterministically to 150byte/s and finishes the transfer at that speed, maybe rising to 170bytes/s by the end of the transfer is I'm lucky. I don't really know where to start looking to solve the problem, it seems everything is functioning as it should at least some of the time as in some cases it will complete the whole transfer at the 5k/s speed. Is it just tcp throttling very harshly (i.e. 50x) when it loses a packet? Is it the Xscale chip scaling down the CPU frequency mid-transfer, I've got no idea how to check this? It is some sort of resonance affect happening with the two radios CCA although I'm not seeing any CCA timeouts. Can any one give any hints what to play with or where to look to try find the cause and get the transfers to run reliabily without the sudden bottoming out of speeds? (if you stop the transfer and initiate a new one immediately it will start at full speed again) Thanks, -YT - To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html
