Hi, I'm generating random requests whose inter-time interval is randomly generated using a exponential distribution, which typically simulates relatively well real traffic. Anyway I'm generating requests with the same parameter with both implementations, so I don't think that's the issue. I may have hit a performance issue in the Serial Forwarder, but I think it's unlikely.
-- Giuseppe Cardone On Thu, Dec 17, 2009 at 12:45 PM, Arik Sapojnik <[email protected]> wrote: > Hi, > > I suppose you are sending your ping requests from client (PC) to server > (mote). > In this case, are you using an inter-packet-gap? This might be the issue. > > Arik > > > > On Thu, Dec 17, 2009 at 12:29, Giuseppe Cardone > <[email protected]> wrote: >> >> Hi, >> >> for my benchmarks I'm generating random request of fixed size. The >> time between two requests is exponentially distributed. As long as The >> rate parameter of the exponential distribution is low enough my >> implementation achieves lower RTTs than blip, but when the rate >> parameter gets higher, blip becomes far better than my implementation. >> Here's a chunk of results obtained using lambda=1.0 (mean = 1.0). The >> first column is the the request size in bytes (not including the IEEE >> 802.15.4 header and the Active Message field), the second one is the >> RTT in ms of my implementation, the third one is the RTT in ms using >> blip. >> >> 08 68 71 >> 16 57 75 >> 24 81 87 >> 32 110 93 >> 40 147 95 >> 48 175 96 >> 56 296 102 >> 64 305 103 >> 72 375 115 >> 80 405 165 >> 88 494 164 >> 96 565 177 >> >> It's hard to say if my implementation has a linear performance with a >> high slope or if it is quadratic. There are some anomalies (for >> example the sharp rise between RTT for requests of 72 and 80 bytes >> using blip, which seems to be a platform issue), but the trend is >> clear: blip sharply outperforms my implementation as the traffic gets >> heavier. I was able to use blip with high lambdas (=5.0) and still >> having decent RTTs: >> >> 8 105 >> 16 98 >> 24 123 >> 32 144 >> 40 190 >> 48 217 >> 56 184 >> 64 203 >> 72 297 >> 80 498 >> 88 738 >> 96 961 >> >> As I said my echo implementation simply uses a Pool component to >> manage the echo requests (I also tried to use a ring buffer written by >> me but the results didn't change much), that's why I suppose that blip >> is particularly clever with buffer management, but still I can't >> understand where the trick is. >> >> -- >> Giuseppe Cardone >> >> >> >> On Thu, Dec 17, 2009 at 7:48 AM, Arik Sapojnik <[email protected]> wrote: >> > Hi, >> > >> > I'm currently investigating the same issue - RTT, delay, throughput... >> > Can you please post your results and the results of blip? >> > >> > Thanks, >> > Arik >> > >> > >> > On Wed, Dec 16, 2009 at 22:06, Giuseppe Cardone >> > <[email protected]> wrote: >> >> >> >> Hi all, >> >> >> >> to get acquainted with TinyOS I'm writing a simple echo application: >> >> it sends back any message it receives. I'm using two TelosB motes and >> >> Tiny OS 2.1 compiled from CVS. The hardware setup is: >> >> >> >> echo client PC --- Proxy running Serial Forwarer connected to a >> >> BaseStation --- Echo server on TelosB >> >> >> >> I'm using a Pool<message_t> to buffer messages on the echo server. >> >> Everything works and I'm happy with it. As comparison I wrote a simple >> >> UDP Echo server using blip, and even if blip has to deal with 6lowpan >> >> it still does a great job and actually under relatively high traffic I >> >> have a much better round trip time using blip than using my >> >> application. I compiled my echo server using the switches: >> >> >> >> -DENABLE_SPI0_DMA -DCC2420_HW_ACKNOWLEDGEMENTS -DTOSH_DATA_LENGTH=102 >> >> >> >> I'm not posting my source code since is pretty trivial: it's just a >> >> echo server that uses a ring buffer to deal with incoming messages. >> >> It's the simplest technique I could think of, and I don't know how >> >> blip can have better performance (and I didn't find any obvious trick >> >> in the source code). How does blip achieve such high performance? Does >> >> it use any trick with buffers to have a performance boost? >> >> >> >> Any help, tip or hint will be greatly appreciated. Thanks. >> >> >> >> -- >> >> Giuseppe Cardone >> >> _______________________________________________ >> >> Tinyos-help mailing list >> >> [email protected] >> >> >> >> https://www.millennium.berkeley.edu/cgi-bin/mailman/listinfo/tinyos-help >> > >> > >> > >> > -- >> > Best Regards, >> > Arik Sapojnik >> > [email protected] >> > > > > > -- > Best Regards, > Arik Sapojnik > [email protected] > _______________________________________________ Tinyos-help mailing list [email protected] https://www.millennium.berkeley.edu/cgi-bin/mailman/listinfo/tinyos-help
