arcadian
I am seeing huge variations in GenServer performance in some of my platforms and I think it is a result of messaging performance on different architectures. Has anyone seen this before or have any ideas as to what is happening or how I would investigate? I want to make sure that I put a fast system into production rather than a slow one.
Specifically, I wrote a short program that spawns an incrementing GenServer (just keeps a count of how many times it is called), and ten Agents that call that GenServer a million times each. On my i5-9500, the program takes 9.5 seconds, and on my i7-9800X, it takes 48 seconds - about 5x longer. Both systems are running on the same OS (FreeBSD) and the same version of elixir and erlang (built using kerl / kiex).
Some thoughts: The i7-9800X is technically a Skylake-X system, which may have the PAUSE issue, and it also has hyperthreading - maybe those could be part of the issue. Or perhaps there is also a way to change the latency of Erlang / Elixir to respond to messages more quickly. Any ideas / suggestions would be welcome.
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Exadra37
I am really curious why this did happen to you, but I don’t have a clue how to help you.
Maybe one of the possible reasons you didn’t get any response on your question, it’s because you didn’t share the code
hubertlepicki
So let me get this right: you have ONE GenServer process that receives millions messages from 10 other processes?
I know nothing about these processes, but in that scenario what would matter a lot is single-threading performance of the CPU, as the nature of work is I assume concentrated in the GenServer processing messages, and also amount of cache in the CPU.
I don’t think this is a real life scenario, by the way, you usually would not have one bottleneck like that by design precisely because it’s a bottleneck.