Running BitBake appears to freeze stdout output for periods, unloose stdout - rinse&repeat

[rkeithhill]

Please use the following bug reporting template to help produce actionable and reproducible issues. Please try to ensure that the reproduction is minimal so that the team can go through more bugs!

• A brief description
  If all cores on the machine are consumed by bitbake, you should observe as we have that bitbake’s progress display will freeze and may not show completion until after it has actually completed and the operator presses Enter numerous times to get it to update

• Expected results
  When we run this on our Ubuntu VM's the BitBake "task progress" output seems more responsive.

• Actual results (with terminal output if applicable)
  Task progress output seems to freeze for long periods of time:
  
  It will stay on a step for a long, long time and then all of a sudden jump ahead a lot.

• Your Windows build number
  15031

• Steps / All commands required to reproduce the error from a brand new installation

1. sudo apt-get install -y gawk wget git-core diffstat unzip texinfo gcc-multilib build-essential chrpath libsdl1.2-dev xterm curl
2. mkdir -p ~/source/gumstix/yocto
3. cd ~/source/gumstix/yocto
4. curl -O http://commondatastorage.googleapis.com/git-repo-downloads/repo > repo
5. chmod a+x repo
6. sudo mv repo /usr/local/bin
7. repo init -u git://github.com/gumstix/Gumstix-YoctoProject-Repo.git
8. repo sync
9. export TEMPLATECONF=meta-gumstix-extras/conf
10. source ./poky/oe-init-build-env
11. export PARALLEL_MAKE="-j 8" # Run nproc to see how many cores you have, give bb all of them
12. export a sanitized PATH env var - remove all the Windows paths - spaces in a path messes up bitbake.
13. bitbake -c fetchall gumstix-console-image # Takes ~40 mins on my machine (4 cores)
14. bitbake gumstix-console-image # Takes ~3 hours on my machine - this is where you see task progress freeze

This all comes from: http://www.hackgnar.com/2015/03/building-yocto-linux-images-for-gumstix.html

BitBake can generate an impressive number of files and suck down all CPUs (100%) and then trade off to 100% disk utilization. It is probably a pretty good stress test. :-)

• Strace of the failing command
  Doesn't fail. Issue is with getting progress stdout to show up in a "timely fashion" in the conhost.

• Required packages and commands to install
  See step 1 above.

See our contributing instructions for assistance.

[rkeithhill]

BTW I notice the antimalware service (AMSI) really sucking down memory - to the tune of 1 GB of PM. I will probably recommend to folks that they temporarily disable Windows Defender real-time protection.