In I.T. we all use all kinds of metrics. Operations teams rely heavily on these, especially when things go south. These metrics are sometimes overrated. Let’s dive into a few real life stories...
As the name would suggest, a Non-Maskable Interrupt (NMI) is an interrupt-like feature that is unaffected by the disabling of classic interrupts. In Linux, NMIs are involved in some features such as performance event monitoring, hard-lockup detector, on demand state...
Traditionally processes are identified globally via process identifiers (PIDs). Due to how pid allocation works the kernel is free to recycle PIDs once a process has been reaped. As such, PIDs do not allow another process to maintain a private, stable reference on a...
RCU has seen lots of changes in the last 2 years. Of note is the RCU flavor consolidation and tree RCU’s lock contention improvements. There have been also improvements with static checking, fixes to scheduler deadlocks and improvements to RCU-based linked lists....
Operating system distributors often face challenges that are somewhat different from that of upstream kernel developers. For instance, some kernel updates often need to stay at least binary compatible with modules that might be “out of tree” for some time. In that...
