I am facing some issues with my Application, and am curious to know the network buffer usage at any given moment.
I am using a CentOS 6 linux Machine.
I know the Default values are present in /proc/sys/net/core/
But i have not been successful in finding the current usage of the Buffers. If any one has any clue on how to find the current usage, please let me know.
Thanks in advance.
If you run ss or netstat the values Recv-Q and Send-Q produce this output.
I.E
$ ss -nt State Recv-Q Send-Q Local Address:Port Peer Address:Port ESTAB 203 0 192.168.1.2:36122 198.xxx.xxx.xxx:80 CLOSE-WAIT 1 0 192.168.1.2:43870 140.xxx.xxx.xxx:80 I have added a simple python program to demonstrate this.
#/usr/bin/python from time import sleep from socket import * import subprocess if __name__ == "__main__": sock = socket(AF_INET, SOCK_STREAM) sock.setsockopt(IPPROTO_TCP, TCP_CORK, 1) sock.connect(('www.google.com', 80)) length = sock.send("GET / HTTP/1.1\r\nHost: www.google.com\r\n\r\n") sport = sock.getsockname()[1] print "Length of sent data: {0}".format(length) subprocess.call(["ss" ,"-nt", "sport", "=", ":{0}".format(sport)]) sock.close() Which produces
Length of sent data: 40 State Recv-Q Send-Q Local Address:Port Peer Address:Port ESTAB 0 40 192.168.1.2:34259 173.194.41.180:80 
tail -f? ss. Not part of the script. In theory you can get the value as it changes in your process thats doing the sockets by using and edge triggered epoll on the socket and then using the FIONREAD request as an ioctl on the socket. There is no mechanisms I am aware to do the same in an unrelated process, without the child having been passed or inherited the file descriptor from the process doing the work. Off the top of my head, try ss -m - should print socket queue sizes, passing the output through grep/cut/awk should sum these up.
