Re-reading this, I'm not sure what either of us are talking about...

About reading a byte and putting it back if select() says the socket is readable: I suppose this is only necessary if conn->c_writewaiter != 0, and maybe only if the pool is paused. And remember that the next select() will often also find the socket is readable, so we must read the next byte (from the socket, not the sockbuf) and put that on the sockbut stack, and so on.

About multiple types of pauses: The concept must be rephrased for that to make sense. The pause mechanism is in effect a pool-wide read/write lock which favors writers over readers. A pool thread readlocks it while running a task. pool_pause() does unlock - writelock. pool_resume() and pool_pausecheck() do unlock - readlock. Now it's possible to talk about moving a few things out of this particular lock, and if necessary protect it with another lock.