Evaluate Profile-Guided Optimization (PGO) and LLVM BOLT

[zamazan4ik]

Hi!

There are a lot of examples of different applications, where Profile-Guided Optimization (PGO) helps a lot with performance - you can check it here. Since PGO shows measurable improvements for other HTTP benchmarking software like Drill and Goose, I think it will be a good idea to test PGO on Siege as well.

I can propose the following action points:

• We need to check the PGO effects on Siege, and if it works well - write a note in the Siege documentation about PGO (like it's already done for ClickHouse).
• I'd appreciate your providing an easy way to build Siege with PGO, and experienced users will be able to do it on their own for their own usage scenarios.
• Investigate LLVM BOLT as an additional optimization step after PGO