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Version 10 (modified by Antoine Martin, 7 years ago) (diff)


[[Image(...)]] Session Info

The "Session Info" dialog is accessible in the following ways:

  • Under "Session Info" in the xpra system tray menu
  • Using the key shortcut Meta + Shift + F11 when an xpra window has the input focus
  • Using the xpra control command "show_session_info" on the server, ie:
    xpra control :10 client show_session_info

It looks like this: small screenshot for the overview


The software pane lists the versions of the most important components of the system for both the client and server: Xpra, (Py)GTK components, (Py)GStreamer, OpenGL, etc..

It allows you to quickly verify that the system is up to date. You can get more detailed version information using xpra info or using the Bug Report Tool.

You can see a screenshot here


The features pane shows more details about sound and picture encoding support and status, packet compression support, client OpenGL library version, bell, cursor, clipboard and mmap features, etc.

You can see a screenshot here


The connection pane shows information about the connection status: the endpoint location, server load, how old the session is and how long it has been connected, the number of packets and bytes received and sent, the type of connection, the encryption used (if any) and the packet compression and encoding algorithms in use, as well as the state of the sound buffers (if used).

You can see a screenshot here


The statistics pane shows various latency and quality data from the server, it can be used to monitor how well the system is self tuning to adapt to the network conditions.

You can see a screenshot here

Server Latency (ms)

This is a measure of how long it takes for:

  • the client to send a "ping" packet
  • the server to receive it, process it and send the "echo" response
  • the client to process the response and calculate the latency

It is very different from an ICMP Ping because it includes on both ends:

  • the full operating system network stack
  • the operating system scheduler
  • the Python interpreter with its threads and locking
  • TCP re-transmits

On a busy system, this value may well go up as other packets are ahead of the send queue at either end. A modern CPU should be able to keep this value below 50ms plus the TCP connection latency. TCP packet drops can cause this value to increase more dramatically.

Client Latency (ms)

Is identical to the server latency above, but it is measured by the server to the client instead.

Batch Delay (ms)

This value represents how long the server waits for window updates to accumulate before actually processing them and sending them to the client. This value changes dynamically to try to provide the best framerate without flooding the connection with compressed pixel data. The value shown here is for all the windows, but each window has its own statistics which can be accessed using xpra info for more details.

It is a function of:

  • the client and server latency (as explained above)
  • the client pixel processing latency (..)
  • how busy the server's compression work queue is (how many regions of screen are waiting to be processed)
  • how many compressed packets are waiting to be sent
  • how well the network layer is performing at sending those packets
  • whether the window is fullscreen or maximized, focused, the type of window, etc..

It should be explained in more detail here: batch delay factors (information is slightly out of date..)

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