Assume you have a node (master) that needs to send very high speed packets with minimal jitter to 10 slaves. So we define 10 slave nodes and interleave a master slot between each slave slot. If each slot is allocated 150 us, then the cycle time will be on the order of 3150 us (10 master slots, 10 different slave slots plus the sync slot). Now, will an asynchronous send_rt() on the master side go out in the next available master slot or will it have to wait until the next cycle? In other words, am I guaranteed that a message sent by my application on the master side will go out no later than 300 us from the send_rt() call (assuming nothing of higher priority is queued) or will it take until the next cycle which could be as long as ~3.15 ms?
Thanks, Bill -----Original Message----- >Date: Mon, 27 Jun 2005 18:32:26 +0200 >From: Jan Kiszka <[EMAIL PROTECTED]> >To: "Kolpak Maximilian (ext)" <[EMAIL PROTECTED]> >CC: "'rtnet-users@lists.sourceforge.net'" <rtnet-users@lists.sourceforge.net> >Subject: Re: [RTnet-users] Problem Round-Trip-Time >Kolpak Maximilian (ext) wrote: >> I have the same problem as described here: >> http://sourceforge.net/mailarchive/message.php?msg_id=11722044 >> <http://sourceforge.net/mailarchive/message.php?msg_id=11722044> >> but unfortunately the given link is dead (fozzie.homelinux......) and i >> would really like to fix that problem. >> >> Is there a new link or a different expaination? >> > >I have no alternative at hand right now. However, thinking a bit about >it you may find the explanation yourself: you have two periodic events, >the TDMA synchronisation packet each cycle and the application issuing >its payload at a different frequency, maybe even on a different system, >thus running with separate clocks. > >Take a look at this attempt to visualise the effect (T_xmit != T_cycle, >"1" and "2" are TDMA slots): > > |<------------T_xmit------------>| > > Send Receive Send Receive > Packet Reply Packet Reply > |_______________ | |___ | > | | | | > Sync Sync | | Sync | | Sync > | | | | >--|----1--2------------|----1--2------------|----1--2------------|---> > t > |<-----T_cycle------>| > > >HTH, >Jan ------------------------------------------------------- SF.Net email is sponsored by: Discover Easy Linux Migration Strategies from IBM. Find simple to follow Roadmaps, straightforward articles, informative Webcasts and more! Get everything you need to get up to speed, fast. http://ads.osdn.com/?ad_id=7477&alloc_id=16492&op=click _______________________________________________ RTnet-users mailing list RTnet-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/rtnet-users
