NIO+Multithreaded TCPSocket listener, very low cpu utilisation

[ade90036]

On Wednesday, 15 November 2017 at 23:04:46 UTC, kdevel wrote:
> On Wednesday, 15 November 2017 at 13:31:46 UTC, Daniel Kozak 
> wrote:
>> This one works ok for me, but I am on linux: 
>> https://dpaste.dzfl.pl/f54decee45bc
>
> It works, but it does not handle two connects in parallel. STR:
>
> 1. start the binary in console 1
> 2. telnet localhost 4444 in console 2
> 3. telnet localhost 4444 in console 3
> 4. enter a [RETURN] in console (3)
>
> observed: nothing (the "thread" handling the first connect 
> blocks)
> expected: response
>
> On my machine defaultPoolThreads() returns 1. This can easily 
> be increased:
>
> ```
>    defaultPoolThreads(8);
> ```
>
> There is also another problem with Socket.select: It may return 
> -1. This frequently happens when the ACCEPT socket is 
> non-blocking and the select is interrupted (by the GC?) then 
> errno == EINTR.
>
> Also not having a timeout in the Socket.select of handle_socket 
> allows for DOS attacks like the one above. In case of a timeout 
> select also returns -1.

Hi Guys,

so i have tried the latest changes with destroy(socket) rather 
than socket.close().

Still the program is extremely slow.

I see that the httpclinet is making successfully 100 request at a 
time and then it freezes for 5/10 seconds and then it process 
another 100 request.

As Kdevel pointed out, this could be related to the Socket.select 
blocking on the interupt or it would be GC kicking in.

I also have seen the value computed for the defaultThread is not 
correct, hence i manually started the TaskPool(int thread) 
manually.

I'm going to share my benchmark program so you can guys test with 
the same tool.

Unfortunately it seems that there is some underline issue which 
is blocking the program and preventing to process all the 
incoming requests in a performant fashion, or at-least utilising 
the full CPU cycles.

reagrds

ade90036