Meltdown and Spectre bugs

Meltdown and Spectre are bugs related to speculative execution in a variety of CPU architectures developed during the past ten to fifteen years and which affect in particular processors from Intel and AMD, including those in use on Compute Canada clusters. A detailed discussion of the two bugs can be found on this page and Compute Canada personnel are currently patching all of the systems vulnerable to attacks based on these bugs. What sort of performance degradation users will observe as a consequence of the patches is dependent on the software you are using and how it interacts with the operating system but in general the more filesystem activity and other input/output operations that a program performs during its execution, the more likely it is to suffer from a slowdown.