Added thread pid to console log for multithread environment

[bspark8]

Currently, nodeos is changing from a single thread to multiple threading system.

• Net plugin opt eos#6725
• Http response thread pool eos#6687
• Optimize transaction signature recovery eos#6471
• Multi-thread transaction key recovery eos#6149
• bnet-plugin

This PR has added thread pid information to the console log for debugging and profiling in multithreading environment.

[heifner]

Is there a reason you can't use: https://en.cppreference.com/w/cpp/thread/get_id ?

[bspark8]

As you say, get_id (pthread_self) is not dependent on the OS and can be used as an uniqe identifier for each thread.
However, since get_id is an identifier of a thread used by library (POSIX thread ID), it is possible to just distinguish between threads, but it is not an OS (system) recognizable value.
that is, it is not directly mapped to the thread pid used by system tools such as linux top. (http://clanguagestuff.blogspot.com/2013/08/gettid-vs-pthreadself.html)
As mentioned above, as more threads come up, we need to know the system usage information (ex: cpu) of the threads to adjust the various setting values. It is also required for system profiling and debugging.
I would appreciate your feedback. Thank you.

[heifner]

Instead of pid we are thinking that we would rather name our threads and use that name instead of the thread-x which is currently used.

https://stackoverflow.com/questions/10121560/stdthread-naming-your-thread

If the threads were named, would that provide what you desire? Or would you still want pid logged? Note that htop will display thread names.

[bspark8]

Cool! until now, if we can distinguish between threads even if not up to pid, I think it will help profiling enough.
I will close this PR. Thank you.