I work on Heroku’s Runtime Infrastructure team, which focuses on most of the underlying compute and containerization here at Heroku. Over the years, we’ve tuned our infrastructure in a number of ways to improve performance of customer dynos and harden security.
We recently received a support ticket from a customer inquiring about poor performance in two system calls (more commonly referred to as syscalls) their application was making frequently: clock_gettime(3) and gettimeofday(2).
In this customer’s case, they were using a tool to do transaction tracing to monitor the performance of their application. This tool made many such system calls to measure how long different parts of their...