20,741
edits
Telnet usage: Difference between revisions
Jump to navigation
Jump to search
m
http://www.mail-archive.com/flightgear-devel@lists.sourceforge.net/msg31243.html
m (http://www.mail-archive.com/flightgear-devel@lists.sourceforge.net/msg01402.html) |
m (http://www.mail-archive.com/flightgear-devel@lists.sourceforge.net/msg31243.html) |
||
| Line 33: | Line 33: | ||
The telnet mechanism is not designed to be high bandwidth. I believe it runs at 5hz? and only processes one line/command per iteration. You could try upping the frequency via the command line, "--props=socket,bi,20,,5500,tcp" (we could change PropsChannel::foundTerminator() to handle several | The telnet mechanism is not designed to be high bandwidth. I believe it runs at 5hz? and only processes one line/command per iteration. You could try upping the frequency via the command line, "--props=socket,bi,20,,5500,tcp" (we could change PropsChannel::foundTerminator() to handle several | ||
commands per line. Commands could be separated with semicolons. Or perhaps some commands could take more than one argument, eg "get /foo/bar /foo/baz"). For higher bandwidth needs, it would work better to send over an FGNetFDM structure (src/Network/net_fdm.hxx) via UDP or some other custom structure. | commands per line. Commands could be separated with semicolons. Or perhaps some commands could take more than one argument, eg "get /foo/bar /foo/baz"). For higher bandwidth needs, it would work better to send over an FGNetFDM structure (src/Network/net_fdm.hxx) via UDP or some other custom structure. | ||
A look at the sources shows that a fixed polling interval is used for telnet - default is 5Hz. So it cannot process more than 5 commands per | |||
second. That's why it's slow. There's better methods of implementing socket communication instead of polling, but I haven't looked into the | |||
module and don't know why this was chosen. The polling interval is configurable though - so you can speed it up. Use: | |||
<pre> | |||
fgfs ..... --telnet=medium,direction,HZ,localhost,PORT,style | |||
</pre> | |||
Use HZ to select the polling frequency (e.g. "100") and PORT for the telnet port (e.g. 9999). The other parameters are unused (it seems) when | |||
using the telnet protocol. Probably there for historic reasons (?). Maybe Curt knows. Remember you have to specify 6 parameters separated by | |||
a "," - otherwise you cannot configure the polling frequency. So call | |||
something like: | |||
<pre> | |||
fgfs ..... --telnet=foo,bar,100,foo,9999,bar | |||
</pre> | |||
TCP sockets are easier to implement for almost all applications, precicely because they are reliable. UDP will only look easier if you plan on skipping the code to recover from a lost packet. Some applications can do this, but the property tree can't -- property access is non-idempotent in the general case. Listeners can have side effects. | TCP sockets are easier to implement for almost all applications, precicely because they are reliable. UDP will only look easier if you plan on skipping the code to recover from a lost packet. Some applications can do this, but the property tree can't -- property access is non-idempotent in the general case. Listeners can have side effects. | ||