05-24-2007
How to Write Linux Friendly Async Socket I/O
I am presently refactoring a windows deamon with an eye towards porting it to linux someday.
Presently the application uses a single background thread and asynchronous socket I/O to implement FTP and HTTP clients in a single switch statement (2000 lines and 100 cases just for the switch statement).
We need to be able to handle 4000 FTP/HTTP servers simultaneously (worst case).
I was going to rewrite this using synchonous socket I/O and lots of threads but I hear that this does not scale well.
Since this is presently a windows app, I was going to use BindIoCompletionCallback thinking that Microsoft implemented this function because they could do it more efficiently than I can (perhaps it is implemented in the kernel?). BindIoCompletion is a function that accepts a socket handle and a function pointer and automagically grabs a thread from a automagically managed thread queue and has the thread execute it when the I/O is complete.
Does the Linux/UNIX API have anything similar to this?
What is the recommmended approach in Linux/UNIX?
(1) A single thread and Async I/O
(2) Lots of threads and synch I/O?
(3) A few threads and async I/O?
Thanks,
Siegfried
10 More Discussions You Might Find Interesting
1. Programming
I have client and server connected.
client write and read from csock.
server write and read from ssock
suppose the server does :
....
close(ssock); //send FIN to client
othertask();
....
READ ERROR
if after the server close() the client does:
...
read(csock,...);
...... (2 Replies)
Discussion started by: gio
2 Replies
2. UNIX for Advanced & Expert Users
Hi,
I am trying to port a networking application to linux, I get error while binding a socket to a port, The port is not used by any application and was verified by using netstat and other tools. I tried a simple socket and bind on a unused port, but even that fails.
Is there any document... (0 Replies)
Discussion started by: venkatesh.n
0 Replies
3. IP Networking
Hi Friends,
I have written a program which will listener for more than 1000 requests per second from a single socket descriptor and then it will process those requestes. Its taking X amount of time. Now i want to reduce that time. Will I can write multiple threads to receive the... (2 Replies)
Discussion started by: pa.chidhambaram
2 Replies
4. Programming
Good evening everyone! :)
I'm doing a small client / server application for sharing files in C, and I am trying to implement the following:
The client of my application sends to the address 255.255.255.255 a message requesting a particular file.In the network there is only one server,... (1 Reply)
Discussion started by: esmeco
1 Replies
5. Programming
Can anyone tell what happens if each end writes at the same time on the same socket ?
- if one of them issues a read() after write() has completed, will it record into the buffer what the other sent ?
ex.
e1 writes to e2 - - - while - - - e2 writes to e1 (at the same time)
e1 read () - what... (1 Reply)
Discussion started by: gendaox
1 Replies
6. Programming
hi, i am newbie of socket. i want to ask some question. if i want to send file from client to server, how do i do? and if i want to send file from server to client, how do i do?
any pro help me and if possible, you can post code for an example
i need it very much
thank you for helping me:)... (1 Reply)
Discussion started by: tung1984
1 Replies
7. Programming
How to know whether socket is ready for write.
select(maxfds, (fd_set *)NULL, &writefds, NULL, &timeout);
By default socket is set for write without checking whether it would block or not? If so how do I know my FD is ready for writing. (3 Replies)
Discussion started by: satish@123
3 Replies
8. IP Networking
Hello,
Our software is using a TCP socket (AF_INET, SOCK_STREAM) to communicate with an Ethernet device. When we send a message, the message object writes itself in full onto the socket's stream buffer before the software invokes send() from socket.h.
I'm still researching, but have 2... (1 Reply)
Discussion started by: bix_20002000
1 Replies
9. Shell Programming and Scripting
Hello all,
I have a requirement to read and write to a tcp socket from an HP-UX shell script. I see a /dev/tcp character device on my servers:
crw-rw-rw- 1 root root 72 0x00004f Mar 28 18:37 /dev/tcp
So I believe this is what I should use. The problem is that all the... (2 Replies)
Discussion started by: lupin..the..3rd
2 Replies
10. Programming
I'm trying to make a "dual/server client" (ipv4,ipv6) with sockets in linux but i don't know how to join both codes. I have a dual client ipv4 and ipv6, but i have problems with the server if you notice the only difference between them it's the AF_INET (pf_inet ipv4, and if_inet6 ipv6) and the port... (3 Replies)
Discussion started by: godna
3 Replies
LEARN ABOUT SUSE
log::log4perl::appender::socket
Appender::Socket(3) User Contributed Perl Documentation Appender::Socket(3)
NAME
Log::Log4perl::Appender::Socket - Log to a socket
SYNOPSIS
use Log::Log4perl::Appender::Socket;
my $appender = Log::Log4perl::Appender::Socket->new(
PeerAddr => "server.foo.com",
PeerPort => 1234,
);
$appender->log(message => "Log me
");
DESCRIPTION
This is a simple appender for writing to a socket. It relies on IO::Socket::INET and offers all parameters this module offers.
Upon destruction of the object, pending messages will be flushed and the socket will be closed.
If the appender cannot contact the server during the initialization phase (while running the constructor "new"), it will "die()".
If the appender fails to log a message because the socket's "send()" method fails (most likely because the server went down), it will try
to reconnect once. If it succeeds, the message will be sent. If the reconnect fails, a warning is sent to STDERR and the "log()" method
returns, discarding the message.
If the option "silent_recovery" is given to the constructor and set to a true value, the behaviour is different: If the socket connection
can't be established at initialization time, a single warning is issued. Every log attempt will then try to establish the connection and
discard the message silently if it fails. If you don't even want the warning, set the "no_warning" option to a true value.
Connecting at initialization time may not be the best option when running under Apache1 Apache2/prefork, because the parent process creates
the socket and the connections are shared among the forked children--all the children writing to the same socket could intermingle
messages. So instead of that, you can use "defer_connection" which will put off making the connection until the first log message is sent.
EXAMPLE
Write a server quickly using the IO::Socket::INET module:
use IO::Socket::INET;
my $sock = IO::Socket::INET->new(
Listen => 5,
LocalAddr => 'localhost',
LocalPort => 12345,
Proto => 'tcp');
while(my $client = $sock->accept()) {
print "Client connected
";
while(<$client>) {
print "$_
";
}
}
Start it and then run the following script as a client:
use Log::Log4perl qw(:easy);
my $conf = q{
log4perl.category = WARN, Socket
log4perl.appender.Socket = Log::Log4perl::Appender::Socket
log4perl.appender.Socket.PeerAddr = localhost
log4perl.appender.Socket.PeerPort = 12345
log4perl.appender.Socket.layout = SimpleLayout
};
Log::Log4perl->init($conf);
sleep(2);
for(1..10) {
ERROR("Quack!");
sleep(5);
}
COPYRIGHT AND LICENSE
Copyright 2002-2009 by Mike Schilli <m@perlmeister.com> and Kevin Goess <cpan@goess.org>.
This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself.
perl v5.12.1 2010-02-07 Appender::Socket(3)