Choose optimal starting parameters for local/mmap connections

[tc424]

Version: 2.4.1-r20894-1

Local/mmap'd connections seem to "speed up" after a few minutes of use - though they are pretty fast to begin with. It seems some starting parameters to the various algorithms are set "pessimistically" which while sensible for "real" network connections probably doesn't make sense for mmap/local. There doesn't seem to be anyway of overriding these choices as the various relevant options are disabled/grayed out for local connections..

< tc424> incidentally, I'm running some more "real world" tests with xpra using a local/mmap connection .. it seems like the latency improves after the session's been open a while (not that it's bad before)
< tc424> almost like some starting parameters are bit pessimistic, and get adjusted upwards?
<@totaam> tc424: that's right
<@totaam> that was done to be able to support ~5Mbps DSL connections
< tc424> ah, OK
< tc424> anyway to override that? Most of the normal controls are disabled for local/mmap...
<@totaam> tc424: yeah, it should be disabled for mmap / local
<@totaam> feel free to create a ticket
<@totaam> so I don't forget to fix that

[Antoine Martin]

Links:

• #1972 UI switch for bandwidth-detection
• #1921 Local xpra is extremely laggy
• #1912 switch for bandwidth detection
• #1855 Continuous Spamming of Network Quality Issues
• #999 catch limited bandwidth issues sooner

When mmap is enabled, we should start with a low batch delay, maximum quality and maximum speed.
The latency values could also be causing problems: if min-latency is very low, any small jitter could make us increase the batch delay.

[Antoine Martin]

Please try the latest beta builds and post xpra info for a session showing the symptoms of this "slow startup".

[Antoine Martin]

Updates:

• r21105: start with higher quality (see #2061) - not that this should really matter since "mmap" uses 100% quality every time, so maybe the only issue you are seeing is the batch delay? (the refresh rate)
• r21121: don't lock the batch delay with mmap enabled - re-evaluate it regularly
• r21115: don't slow down too much just because other windows are maximized or fullscreen - see ticket:1921#comment:34

@tc424: is that better?

[migration script]

this ticket has been moved to: ​https://github.com/Xpra-org/xpra/issues/2037