Re: Socket server + thread: cpu usage
On Tuesday, 29 April 2014 at 17:19:41 UTC, Adam D. Ruppe wrote:
On Tuesday, 29 April 2014 at 17:16:33 UTC, Tim wrote:
Is there anything I'm doing wrong?
You should be using a blocking socket. With them, the operating
system will put your thread on hold until a new connection
comes in. Without them, it will endlessly loop doing absolutely
nothing except checking if a new connection is there yet.
Horribly, horribly inefficient.
Blocking sockets are now working as expected, but I've one
problem. When I do the following in my server-accept-thread:
while (m_oSocket.isAlive)
{
oSocketSet.reset();
oSocketSet.add(m_oSocket);
nAcceptedSockets = Socket.select(oSocketSet, null, null,
25.msecs);
if (nAcceptedSockets 0)
{
// Do something...
}
}
... and the following in my client:
void connect()
{
m_oSocket = new TcpSocket(AddressFamily.INET);
m_oSocket.connect(new InternetAddress(127.0.0.1, 12345));
}
The CPU usage is low as long as my connect is connected. When I
disconnect the client using the following few lines:
void disconnect()
{
m_oSocket.shutdown(SocketShutdown.BOTH);
m_oSocket.close();
}
... the CPU usage goes up. I think that SocketShutdown.BOTH
causes Socket.select to fail which results in an endless loop.
Any suggestions how to handle that problem?
@Ali Çehreli: Thanks, didn't know that UFCS can also handle such
constructs :)
Re: Socket server + thread: cpu usage
On Thursday, 1 May 2014 at 08:08:37 UTC, Tim wrote:
On Tuesday, 29 April 2014 at 17:19:41 UTC, Adam D. Ruppe wrote:
On Tuesday, 29 April 2014 at 17:16:33 UTC, Tim wrote:
Is there anything I'm doing wrong?
You should be using a blocking socket. With them, the
operating system will put your thread on hold until a new
connection comes in. Without them, it will endlessly loop
doing absolutely nothing except checking if a new connection
is there yet. Horribly, horribly inefficient.
Blocking sockets are now working as expected, but I've one
problem. When I do the following in my server-accept-thread:
while (m_oSocket.isAlive)
{
oSocketSet.reset();
oSocketSet.add(m_oSocket);
nAcceptedSockets = Socket.select(oSocketSet, null, null,
25.msecs);
if (nAcceptedSockets 0)
{
// Do something...
}
}
... and the following in my client:
void connect()
{
m_oSocket = new TcpSocket(AddressFamily.INET);
m_oSocket.connect(new InternetAddress(127.0.0.1, 12345));
}
The CPU usage is low as long as my connect is connected. When I
disconnect the client using the following few lines:
void disconnect()
{
m_oSocket.shutdown(SocketShutdown.BOTH);
m_oSocket.close();
}
... the CPU usage goes up. I think that SocketShutdown.BOTH
causes Socket.select to fail which results in an endless loop.
Any suggestions how to handle that problem?
@Ali Çehreli: Thanks, didn't know that UFCS can also handle
such constructs :)
Small correction: The CPU usage is low as long as my client is
connected. When I disconnect the client using the following few
lines:
Re: Socket server + thread: cpu usage
On Thursday, 1 May 2014 at 08:08:37 UTC, Tim wrote: ... the CPU usage goes up. I think that SocketShutdown.BOTH causes Socket.select to fail which results in an endless loop. Any suggestions how to handle that problem? It shouldn't be here, disconnect would affect the new socket, and you're calling select on the accepting socket, which is still good to accept a new connection. What's your code look like for handing a socket returned by accept?
Re: Socket server + thread: cpu usage
On Tuesday, 29 April 2014 at 17:44:21 UTC, Tim wrote:
On Tuesday, 29 April 2014 at 17:35:08 UTC, Tim wrote:
On Tuesday, 29 April 2014 at 17:19:41 UTC, Adam D. Ruppe wrote:
On Tuesday, 29 April 2014 at 17:16:33 UTC, Tim wrote:
Is there anything I'm doing wrong?
You should be using a blocking socket. With them, the
operating system will put your thread on hold until a new
connection comes in. Without them, it will endlessly loop
doing absolutely nothing except checking if a new connection
is there yet. Horribly, horribly inefficient.
Alright, this would solve the server-cpu-usage-problem. But
what about incoming connections? When I create a new thread
and use non-blocking socket I've exactly the same problem. I
can also solve this problem by using blocking sockets, but
what happens if I do the following:
while(oMyBlockingSocket.isAlive)
{
oMyBlockingSocket.receive(...);
}
... and close the connection on the client side? I would never
receive anything and receive() waits never comes back or would
this throw an exception or similar?
Sorry... I totally forgot... I can use SocketSet's as I already
asked:
http://forum.dlang.org/thread/ogghezngzrvvoqaod...@forum.dlang.org#post-kivp3e:24jif:241:40digitalmars.com
... but I thought it's also possible using non blocking sockets
by using Thread.yield().
You want to add something like this to your while loop:
Thread.sleep( dur!(msecs)( 20 ) );
That will give back some time to the CPU.
Re: Socket server + thread: cpu usage
On 04/30/2014 04:24 PM, Damian Day wrote: Thread.sleep( dur!(msecs)( 20 ) ); Going off topic, the UFCS syntax makes that code much more readable. :) Thread.sleep(20.msecs); Ali
Socket server + thread: cpu usage
Hi guys,
I've the following snipped:
TcpSocket oSocket = new TcpSocket(AddressFamily.INET);
oSocket.bind(new InternetAddress(127.0.0.1, 12345));
oSocket.blocking(false);
oSocket.listen(0);
while(true)
{
try
{
Socket oRequestSocket = oSocket.accept();
Request oRequest = new Request(oRequestSocket);
oRequest.start(); // Start request thread
}
catch (SocketAcceptException oException)
{
Thread.yield();
}
}
When I execute the code above, the while(true)-loop uses nearly
100% (1 complete cpu). When I connect to the server multiple
times (note that each Request-Thread has it's own
while(oRequestSocket.isAlive)-loop) the cpu usage easily reaches
120, 130... 200 and more cpu usage.
Is there anything I'm doing wrong? I don't want use blocking
sockets... how to handle 100 or 1000 connections when the main
server thread already consumes 1 cpu?
Re: Socket server + thread: cpu usage
On Tuesday, 29 April 2014 at 17:16:33 UTC, Tim wrote: Is there anything I'm doing wrong? You should be using a blocking socket. With them, the operating system will put your thread on hold until a new connection comes in. Without them, it will endlessly loop doing absolutely nothing except checking if a new connection is there yet. Horribly, horribly inefficient.
Re: Socket server + thread: cpu usage
On Tuesday, 29 April 2014 at 17:19:41 UTC, Adam D. Ruppe wrote:
On Tuesday, 29 April 2014 at 17:16:33 UTC, Tim wrote:
Is there anything I'm doing wrong?
You should be using a blocking socket. With them, the operating
system will put your thread on hold until a new connection
comes in. Without them, it will endlessly loop doing absolutely
nothing except checking if a new connection is there yet.
Horribly, horribly inefficient.
Alright, this would solve the server-cpu-usage-problem. But what
about incoming connections? When I create a new thread and use
non-blocking socket I've exactly the same problem. I can also
solve this problem by using blocking sockets, but what happens if
I do the following:
while(oMyBlockingSocket.isAlive)
{
oMyBlockingSocket.receive(...);
}
... and close the connection on the client side? I would never
receive anything and receive() waits never comes back or would
this throw an exception or similar?
Re: Socket server + thread: cpu usage
On Tuesday, 29 April 2014 at 17:35:08 UTC, Tim wrote:
On Tuesday, 29 April 2014 at 17:19:41 UTC, Adam D. Ruppe wrote:
On Tuesday, 29 April 2014 at 17:16:33 UTC, Tim wrote:
Is there anything I'm doing wrong?
You should be using a blocking socket. With them, the
operating system will put your thread on hold until a new
connection comes in. Without them, it will endlessly loop
doing absolutely nothing except checking if a new connection
is there yet. Horribly, horribly inefficient.
Alright, this would solve the server-cpu-usage-problem. But
what about incoming connections? When I create a new thread and
use non-blocking socket I've exactly the same problem. I can
also solve this problem by using blocking sockets, but what
happens if I do the following:
while(oMyBlockingSocket.isAlive)
{
oMyBlockingSocket.receive(...);
}
... and close the connection on the client side? I would never
receive anything and receive() waits never comes back or would
this throw an exception or similar?
Sorry... I totally forgot... I can use SocketSet's as I already
asked:
http://forum.dlang.org/thread/ogghezngzrvvoqaod...@forum.dlang.org#post-kivp3e:24jif:241:40digitalmars.com
... but I thought it's also possible using non blocking sockets
by using Thread.yield().
Re: Socket server + thread: cpu usage
On Tue, 29 Apr 2014 17:16:32 +, Tim wrote:
Hi guys,
I've the following snipped:
TcpSocket oSocket = new TcpSocket(AddressFamily.INET); oSocket.bind(new
InternetAddress(127.0.0.1, 12345)); oSocket.blocking(false);
oSocket.listen(0);
while(true)
{
try {
Socket oRequestSocket = oSocket.accept();
Request oRequest = new Request(oRequestSocket);
oRequest.start(); // Start request thread
}
catch (SocketAcceptException oException)
{
Thread.yield();
}
}
When I execute the code above, the while(true)-loop uses nearly 100% (1
complete cpu). When I connect to the server multiple times (note that
each Request-Thread has it's own while(oRequestSocket.isAlive)-loop) the
cpu usage easily reaches 120, 130... 200 and more cpu usage.
Is there anything I'm doing wrong? I don't want use blocking sockets...
how to handle 100 or 1000 connections when the main server thread
already consumes 1 cpu?
If you use blocking sockets, you should probably spawn a new thread for
each client. If you use non-blocking sockets, you need to use poll or
select to wait for incoming connections or data.
