[Bug 1183672] Re: update-manager grabs major share of CPU&RAM when browsing list items

[Mark]

I see this problem too. The amount of CPU time wasted seems to be
proportional to the length of the package's changelog. A kernel package
with very long changelog causes update-manager to hang using 100% CPU
for a long time, whereas it only hangs very briefly if you click a
package whose changelog is smaller.

This happens even if the user did not click "Technical description" so
the changelog is not shown on-screen.

It's really annoying. Even if you're just un-checking boxes to deselect
packages, you get the 100% CPU hang. (Try moving down the list un-
checking several boxes quickly.)

To reproduce should be fairly easy:
- Run "top" (or some other load monitor) in a terminal.
- Run update-manager and wait until the list of available updates appears.
- Click the top item, then keep tapping cursor-down to move to the next one.
- If you hit an update with a long changelog (e.g. kernel package), notice that CPU usage goes to 100% for a long time.

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https://bugs.launchpad.net/bugs/1183672

Title:
  update-manager grabs major share of CPU&RAM when browsing list items

Status in update-manager package in Ubuntu:
  Confirmed

Bug description:
  The moment e.g. "Header files to the Linux kernel version 3.2.0" or
  "Linux kernel headers vor version 3.2.0 on 32 bit x86 SMP" (-44
  thereof, i.e. between second and subsequent kernel-related entries
  from the top today) is highlighted, update-manager 1:0.156.14.11 on
  Ubuntu 12.04.2 LTS deselects the item, reproducibly grabs 100% CPU,
  becomes barely responsive for minutes (on a 2.66 MHz Dual Core) and
  starts leaking memory (process had to be user-terminated when taking
  more than 30% of 2 GB). Neither delays nor excessive RAM consumption
  occur when moving the selection within the lower, non-kernel items of
  the update list.

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