[libmicrohttpd] Busy waiting up to one second using connection timeout

[Irion, Alexander]

Hello!

I discovered a problem with closing connections, when MHD_OPTION_CONNECTION_TIMEOUT is used. When I set the timeout option to 3 seconds and connect with a browser, I get a timeout value from MHD_get_timeout() of 3000 ms returned. I then sleep the desired time and call MHD_run again(). Then, MHD_get_timeout() returns repetitive a timeout of 0 which causes thousands of calls to MHD_run(), taking up several hundred milliseconds and burning CPU time.

I use an external event loop with MHD_DAEMON_INFO_EPOLL_FD.

As reason I found that the condition  timeout < (MHD_monotonic_sec_counter () - connection->last_activity) will not be true, after waiting the timeout time. The right side will be equal to timeout, so the connection is not closed, MHD_get_timeout() continues to return a timeout value of 0, and this runs repetitively in a loop for some thousand iterations, until the time jumps to the next second.

In the attachment please find a small patch for fixing this issue. It's just turning the < into a <=.

Regards,

Alexander Irion

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0001-Fix-busy-waiting-up-to-one-second-using-connection-t.patch
Description: 0001-Fix-busy-waiting-up-to-one-second-using-connection-t.patch