Visualizing Process Execution
In Visualizing Process Snapshots I showed processes and their parent-child hierarchy over time, using snapshots of process information. This approach misses short-lived processes that occur between the snapshots. Here I’ll fill in the gaps using system tracing, visualizing all processes that occurred. Snapshots vs Tracing 1 second snapshots (eg, top) [...]
In: Performance · Tagged with: cloud, dtrace, experimental, performance, visualizations
Activity of the ZFS ARC
Disk I/O is still a common source of performance issues, despite modern cloud environments, modern file systems and huge amounts of main memory serving as file system cache. Understanding how well that cache is working is a key task while investigating disk I/O issues. In this post, I’ll show the activity of the ZFS file [...]
In: Kernel · Tagged with: ARC, dtrace, performance, ZFS
Flame Graphs
MySQL Flame Graph Determining why CPUs are busy is a routine task for performance analysis, which often involves profiling stack traces. Profiling by sampling at a fixed rate is a coarse but effective way to see which code-paths are hot (busy on-CPU). It usually works by creating a timed interrupt that collects the current program [...]
In: Performance · Tagged with: dtrace, performance, profiling, visualizations
