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]
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