[Python-apps-team] Bug#745357: xpra: After an update XPRA became slow, the server has high CPU usage

[Alex]

Package: xpra
Version: 0.12.3+dfsg-1 (server), 0.3.11+dfsg-1(client)
Severity: normal

Dear Maintainer,
*** Please consider answering these questions, where appropriate ***

   * What led up to the situation?
A recent update of the server. I'm running debian jessie on the server and debian wheezy on the client. I just have updated the server version to 0.12.3+dfsg-1 and the problem appears. The client xpra version is 0.3.11+dfsg-1
   * What exactly did you do (or not do) that was effective (or
     ineffective)?
I'm using xpra in a home wired network. It's configured for minimal CPU usage. It is set to zero compression in both server config and client command line options, codec is set to rgb (in server config) and rgb24 (in client command line, that version of xpra does not recognize "rgb" option), pulseaudio disabled, and connection is via tcp sockets. This was running seamlessly until today.
Now xpra is terribly slow with most of the codecs (except jpeg), and the server CPU utilization is near 100% when I only scroll a fullscreen app in xpra window.
   * What was the outcome of this action?
I tried to switch codecs and compression via the client systray icon, and I've found that only with jpeg codec xpra performance is fair enough. I've also found that the "Compression" must be set to "none" or the connection would be lost. I tried to change compression level in server config but the result was the same.
   * What outcome did you expect instead?
I think that without any expenses for compression and encryption, with pure rgb over tcp, xpra must show max performance and minimal CPU time. I think there's something wrong when it's not true.

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-- System Information:
Debian Release: 7.4
  APT prefers stable
  APT policy: (500, 'stable')
Architecture: amd64 (x86_64)

Kernel: Linux 3.2.0-4-amd64 (SMP w/2 CPU cores)
Locale: LANG=ru_RU.UTF-8, LC_CTYPE=ru_RU.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/dash

Versions of packages xpra depends on:
ii  libavcodec53       6:0.8.10-1
ii  libc6              2.13-38+deb7u1
ii  libswscale2        6:0.8.10-1
ii  libvpx1            1.1.0-1
ii  libx11-6           2:1.5.0-1+deb7u1
ii  libx264-123        2:0.123.2189+git35cf912-1
ii  python             2.7.3-4+deb7u1
ii  python-dbus        1.1.1-1
ii  python-gtk2        2.24.0-3+b1
ii  python-imaging     1.1.7-4
ii  python-wimpiggy    0.3.11+dfsg-1
ii  x11-xserver-utils  7.7~3
ii  xvfb               2:1.12.4-6+deb7u2

Versions of packages xpra recommends:
ii  xserver-xorg-video-dummy  1:0.3.5-2+b1

Versions of packages xpra suggests:
ii  openssh-client  1:6.0p1-4+deb7u1
pn  openssh-server  <none>

-- no debconf information