C++ Socket Server – Unable to saturate CPU

by

boost::asio is not as thread-friendly as you would hope – there is a big lock around the epoll code in boost/asio/detail/epoll_reactor.hpp which means that only one thread can call into the kernel’s epoll syscall at a time. And for very small requests this makes all the difference (meaning you will only see roughly single-threaded performance).

Note that this is a limitation of how boost::asio uses the Linux kernel facilities, not necessarily the Linux kernel itself. The epoll syscall does support multiple threads when using edge-triggered events, but getting it right (without excessive locking) can be quite tricky.

BTW, I have been doing some work in this area (combining a fully-multithreaded edge-triggered epoll event loop with user-scheduled threads/fibers) and made some code available under the nginetd project.

More Related Contents:

  1. How to increase thread priority in pthreads?
  2. Is it safe to fork from within a thread?
  3. Cancelling boost asio deadline timer safely
  4. How to name a thread in Linux? [duplicate]
  5. Boost::asio – how to interrupt a blocked tcp server thread?
  6. c++ work queues with blocking
  7. How are user-level threads scheduled/created, and how are kernel level threads created?
  8. C++ Boost ASIO simple periodic timer?
  9. Exception running boost asio ssl example
  10. some problems about c++ try catch [closed]
  11. Undefined reference to pthread_create in Linux
  12. How can I create directory tree in C++/Linux?
  13. understanding of pthread_cond_wait() and pthread_cond_signal()
  14. How to implement multithread safe singleton in C++11 without using
  15. Difference between pointer and reference as thread parameter
  16. std::vector, thread-safety, multi-threading
  17. How to use SQLite in a multi-threaded application?
  18. boost asio ssl async_shutdown always finishes with an error?
  19. Boost async_* functions and shared_ptr’s
  20. Delayed start of a thread in C++ 11
  21. C++11 STL containers and thread safety
  22. Heap corruption under Win32; how to locate?
  23. C++ Thread Pool [closed]
  24. OpenMP: What is the benefit of nesting parallelizations?
  25. version `CXXABI_1.3.8′ not found (required by …) [duplicate]
  26. Find available network interfaces in C/C++? [closed]
  27. Why there are three unexpected worker threads when a Win32 console application starts up? [duplicate]
  28. Is a memory barrier required to read a value that is atomically modified?
  29. How to get the username in C/C++ in Linux?
  30. How to assert if a std::mutex is locked?

Leave a Comment