CPU usage pegged at 100%

[pcbeard]

Using bin/ftpdrb on macOS with ruby 1.4, Activity Monitor shows ruby using 6 threads and 100% of a CPU. Is the server doing a lot of polling? In my configuration, there are 3 active server connections that are otherwise idle most of the time.

[wconrad]

No polling. Ffpd runs one listener thread and then one thread per connection. All IO is supposed to be blocking but what you are seeing makes me wonder.

…

On Jun 25, 2017 08:47, "pcbeard" ***@***.***> wrote: Using bin/ftpdrb on macOS with ruby 1.4, Activity Monitor shows ruby using 6 threads and 100% of a CPU. Is the server doing a lot of polling? — You are receiving this because you are subscribed to this thread. Reply to this email directly, view it on GitHub <#47>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AB2JiA6biP4atwrp-Bk_EqSWJDXgTsbRks5sHoD6gaJpZM4OEpDU> .

[pcbeard]

Even w/o any connections, simply starting the server by running bin/fptdrb, here's what top shows:

PID    COMMAND      %CPU TIME     #TH   COW     #PORT MEM    PURG   CMPRS  STATE    UID  #WQ  BOOSTS                %CPU_ME
17058  ruby         94.2 02:02.52 3/1   237     24    8960K  0B     0B     running  5322 0    *0[1]                 0.00000

[wconrad]

The problem was a busy-loop in bin/ftpdrb.
I can't release a new gem right now--something in my test/release setup for ftpd has gone wrong, and I can't troubleshoot it right now.

[pcbeard]

Yes, I just confirmed that too. Here:

    def run
      puts "FTP server started. (Press CRL+C to stop it)"
      connection_info.each do |key, value|
        puts "#{key}: #{value}"
      end
      $stdout.flush
      begin
        loop{}
      rescue Interrupt
        puts "\nClosing FTP server..."
      end
    end

What's your proposed fix? I think the easiest would be to simply change that loop to a call to the server thread's join method.

[pcbeard]

Added a pull request.

[wconrad]

I think your fix is fine. I'll probably back out my fix and accept your PR after I get some of ftpd's housekeeping taken care of.

[wconrad]

I've released a new version of the gem which includes my fix for this issue. Leaving this issue open tor remind me to replace it with your fix.

[pcbeard]

Did you ever consider my fix?

[wconrad]

@pcbeard I would love to use your fix. I haven't pulled it in because my upkeep of ftpd stopped when recent versions of Ruby broke the double-bag-ftps gem that ftpd uses for ftps support, and I don't know what the fix for that is. I suppose I could officially not support more recent Ruby versions, but that bothers me.