Wednesday 4 May 2016

Some extra features landing in stress-ng 0.06.00

Recently I've been adding a few more features into stress-ng to get improve kernel code coverage.   I'm currently using a kernel built with gcov enabled and using the most excellent lcov tool to collate the coverage data and produce some rather useful coverage charts.

With a gcov enabled kernel, gathering coverage stats is a trivial process with lcov:

 sudo apt-get install lcov  
 sudo lcov --zerocounters  
 stress-ng --seq 0 -t 60  
 sudo lcov -c -o kernel.info  
 sudo genhtml -o html kernel.info  

..and the html output appears in the html directory.

In the latest 0.06.00 release of stress-ng, the following new features have been introduced:

  • af-alg stressor, added skciphers and rngs
  • new Translation Lookaside Buffer (TLB) shootdown stressor
  • new /dev/full stressor
  • hdd stressor now works through all the different hdd options if --maximize is used
  • wider procfs stressing
  • added more keyctl commands to the key stressor
  • new msync stressor, exercise msync of mmap'd memory back to file and from file back to memory.
  • Real Time Clock (RTC) stressor (via /dev/rtc and /proc/driver/rtc)
  • taskset option, allowing one to run stressors on specific CPUs (affinity setting)
  • inotify stressor now also exercises the FIONREAD ioctl()
  • and some bug fixes found when testing stress-ng on various architectures.
The --taskset option allows one to keep stress-ng stressors bound to specific CPUs, for example, to run 5 CPU stressors tied to CPUs 1, 3, 5, 6 and 7:

 stress-ng --taskset 1,3,5-7 --cpu 5  

..thanks to Jim Rowan (Intel) for the CPU affinity ideas.

stress-ng 0.06.00 will be landing in Ubunty Yakkety soon, and also in my power utilities PPA ppa:colin-king/white