Do not blindly close the sockets created by socketpair() when
finishing up or destroying a task.
Under heavy load this could turn into a race condition where
the task thread closes its endpoint when at the same time
a new task is registered and socketpair() returns the recently
closed socket back to a new task.
When the task that finished then gets destroyed it closes
the endpoint registered to a new task instead causing Kore
to fatal() out when attempting to read from said socket.
This configuration option limits the maximum number
of connections a worker process can accept() in a single
event loop.
It can be used to more evenly spread out incoming connections
across workers when new connections arrive in a burst.
In cases where accept() failed Kore would not relinquish the
lock towards other worker processes.
This becomes evident when dealing with a high number of concurrent
connections to the point the fd table gets full. In this scenario
the worker with the full fd table will spin on attempt to accept
newer connections.
As a bonus, Kore now has allows exactly up to worker_max_connections
of connections per worker before no longer attempting to grab the
accept lock.
* Always start listening on the task its socket endpoint when
called kore_task_run() instead of at kore_task_bind_request().
* Disable read events on the task its socket endpoint when
kore_task_handle() is called for a finished task. Stops us
from entering a busy loop until kore_task_destroy() is called.
Introduces two new configuration knobs:
* socket_backlog (backlog for listen(2))
* http_request_limit
The second one is the most interesting one.
Before, kore would iterate over all received HTTP requests
in its queue before returning out of http_process().
Under heavy load this queue can cause Kore to spend a considerable
amount of time iterating over said queue. With the http_request_limit,
kore will process at MOST http_request_limit requests before returning
back to the event loop.
This means responses to processed requests are sent out much quicker
and allows kore to handle any other incoming requests more gracefully.
Do not link against libstdc++ when not having any C++ files.
Let the compiler decide what subprocess to use for compiling
certain files, thus killing the CXX need. Can be overwritten
in the same old default in CC.
Signals Kore to not free any pointer set in req->hdlr_extra.
Useful in certain scenarios where you have data per request
bound to something in memory but do not want to lose it when
the request is freed by Kore.
Set this flag before your handler returns.
Joris Vink
Geenz