3.0 Changelog

From ChronOS Linux

Changes made between Beta 2.8 and 3.0.

Kernel

• Moved from kernel version 2.6.33.9 to 3.0.24, and updated to the 3.0.24-rt42 version of the PREEMPT_RT patch.
• Fixed several bugs resulting from changes made between the 2.6.33.9 and 3.0.24 kernels.
• Allow processes to exit gracefully, even if inside a real-time segment.
• Ported to ARM architecture.
  • Made MCS Lock implementation more generic. This will allow for easier porting of ChronOS to additional platforms. While the current 'generic' implementation is optimized for x86_64, it has been done in a way that encourages optimized architecture-specific versions.
• Added DEBUG_CHRONOS config option which adds several checks in the kernel which are useful for debugging (including warning when a ChronOS task blocks inside its RT segment, and when it exits prematurely).
• Converted all scheduler-managed lists to Linux's 'struct list_head' style lists, and added '#define' constants for referencing them by name.
• United the initialization of the /proc/chronos/ entries, so that directory is guaranteed to always be created, and made /proc/chronos/schedulers always available, even if scheduling statistics are not enabled.

Userspace

• Re-wrote entire sched_test_app for better modularity, portability, and expandability.
  • Remove dependence on QT
  • Add three timing methods: WCET, average-case, and timer-polling.
  • Add array-walk (forwards, backwards, and random), linked list and BST traversal workloads for memory-intensive testing.
  • Improve accuracy of slope-generation mechanism.
  • Add ability to configure groups of threads, which all share memory, and allow that working set size to be configurable via the taskset files.
• Ported to ARM (fixed several overflow and type issues)