B.8. Changes in SystemTap

Red Hat Developer Toolset 3.0 is distributed with SystemTap 2.5, which provides a number of bug fixes and feature enhancements over the Red Hat Enterprise Linux system version and the version included in the previous release of Red Hat Developer Toolset. Below is a list of new features in this release.

B.8.1. Changes Since Red Hat Developer Toolset 2.1

The following features have been added since the release of SystemTap included in Red Hat Developer Toolset 2.1:
  • The tapset library no longer signals certain types of errors by returning dummy values. Instead, fully-fledged SystemTap errors are generated that can be caught using the try { } catch { } construct. Alternatively, other tapset functions may be used to return user-specified dummy values.
  • The dyninst backend, which can be enabled by passing the --runtime=dyninst or --dyninst parameter to stap, has had a number of compatibility and performance improvements added.
  • The quality and detail of error messages have been greatly improved. The improvements include colorization, manual-page cross-referencing, and suggestions for correcting typing mistakes.
  • The prologue analysis for placing function-entry probes has been improved.
  • A function().callee(...) type of probe for probing outgoing calls from given functions has been introduced.
  • Many new functions have been added to the tapset library.
The following new features are only available on Red Hat Enterprise Linux 7 systems:
  • SecureBoot support via a stap-server has been extended with key generation and module-signing.
  • Support has been added for probing virtual machines from the host without a network. The probing requires a minimal runtime installed within the virtual machine, which communicates through the virtio-serial device.
  • Support has been added for using .gnu_debugdata symbol tables in base executables to resolve certain probe symbols or addresses without the need for full debuginfo.

Note

Incompatibility problems with old scripts can be resolved using the backward-compatibility option, --compatible version, where version is the version of SystemTap for which the script was written.