Query Capacity library (qclib)

This page is the 'homepage' of the Linux on z Systems qclib package ('qclib' for 'Query Capacity library').


qclib provides a C API for extraction of system information for Linux on IBM Z.
For instance, it will provide the number of CPUs

  • on the machine (CEC, Central Electronic Complex) layer
  • on the PR/SM (Processor Resource/Systems Manager) layer, i.e. visible to LPARs, including LPAR groups
  • in z/VM hosts, guests and CPU pools
  • in KVM hosts and guests

This allows calculating the upper limit of CPU resources a highest level guest can use.
For example: If an LPAR on a z13 provides 4 CPUs to a z/VM hypervisor, and the hypervisor provides 8 virtual CPUs to a guest, qclib can be used to retrieve all of these numbers, and it can be concluded that not more capacity than 4 CPUs can be used by the software running in the guest.

Refer to the README delivered with qclib in the downloadable package for installation instructions, documentation, and more.

Download area - current: Query Capacity library package

Date Component Comment
2018-07-03 qclib-1.4.1.tgz / MD5 Bugfix release.

Previous qclib releases

Date Component Comment
2018-04-10 qclib-1.4.0.tgz / MD5 Add SMT support.
2018-01-18 qclib-1.3.1.tgz / MD5 Bugfix release.
2017-10-27 qclib-1.3.0.tgz / MD5 Support STHYI instruction in LPAR environments.
2016-06-10 qclib-1.2.0.tgz / MD5 Add support for LPAR group capping. Expand hypfs usage. Provide detailed CPU counts for KVM hosts and guests.
2016-02-15 qclib-1.1.0.tgz / MD5 Second release: minor enhancements and bug fixes.
2015-08-28 qclib-1.0.0.tgz / MD5 Initial release.