- update to 5.9.0:
* [Linux]: `cpu_freq()`_ is slow on systems with many CPUs. Read current
frequency values for all CPUs from ``/proc/cpuinfo`` instead of opening many
files in ``/sys`` fs. (patch by marxin)
* `NoSuchProcess`_ message now specifies if the PID has been reused.
* error classes (`NoSuchProcess`_, `AccessDenied`_, etc.) now have a better
formatted and separated ``__repr__`` and ``__str__`` implementations.
* [Linux]: `disk_partitions()`_: convert ``/dev/root`` device (an alias
used on some Linux distros) to real root device path.
* ``PSUTIL_DEBUG`` mode now prints file name and line number of the debug
messages coming from C extension modules.
* rewrite HISTORY.rst to use hyperlinks pointing to psutil API doc.
* [Linux]: `wait_procs()`_ should catch ``subprocess.TimeoutExpired``
exception.
* [Linux]: `sensors_battery()`_ can raise ``TypeError`` on PureOS.
* [Linux]: psutil does not handle ``ENAMETOOLONG`` when accessing process
file descriptors in procfs. (patch by Nikita Radchenko)
* **[critical]**: ``memoize_when_activated`` decorator is not thread-safe.
* **[critical]**: `process_iter()`_ is not thread safe and can raise
``TypeError`` if invoked from multiple threads.
* [Linux]: `cpu_freq()`_ return order is wrong on systems with more than
9 CPUs.