- People still don’t understand how computers work. This is great news for me as a performance engineer and tester, because that means I will continue to be employed. But this is bad news because we aren’t making any headway on improving the state of the industry’s maturity around system performance.
- There are a few new cool tools to use for Linux performance work, like latencytop, which might be even better than powertop, and “sar –B” or “sar –r” for memory diagnosis -- and also don’t forget that you might need to dig into the source code to find the root cause of a performance limitation.
- Don’t forget that Linux kernels were created first as desktop operating systems and there is still a tremendous amount of code that still isn’t optimized for massively scalable server optimization – look for NUMA limitations, single-threaded I/O drivers and virtual memory management assumptions.
- Correlation is not causation: you might not be aware that just because you correlate activities between system performance metrics or measures graphed on a mutual timeline, doesn’t absolutely mean that they are actually linked causally. This includes misleading bottlenecks: like increased disk I/O is not a disk bottleneck, if there’s a swap condition due to limited memory.
What I learned from Artur Bergman in less than 18 minutes
Thanks to @lounibos retweet from OreillyMedia on Twitter, I recently came across this presentation from Artur Bergman given at Velocity EU Berlin last month. To be totally honest, I had previously never heard of Artur Bergman, but I had heard of his company Fastly (www.fastly.com).