family

role

program

address:port[-range]

use

sdp

connect

*

192.168.1.0/24:*

Use SDP by ttcp when it connects to port 5001 of any machine

 

family

role

program

address:port[-range]

use

sdp

listen

ttcp

*:5001

Use TCP for any program with name starting with ttcp* serving ports 22 to 25

 

family

role

program

address:port[-range]

use

tcp

server

ttcp*

*:22-25

Listen on both TCP and SDP by any server that listen on port 8080

 

family

role

program

address:port[-range]

use

both

server

*

*:8080

Connect through SDP and if it fails then fall back to TCP to hosts on 11.4.8.* port 22

 

family

role

program

address:port[-range]

use

both

connect

*

11.4.8.0/24:22

 

 

 

 

 

NOTE: In the absence of rules or if all the rules are commented out, all the connections use SDP by default.

After editing the libsdp.conf file to suite the requirements, preload the libsdp.so library before executing the application. Run the following command to preload the library:

# export LD_PRELOAD=/usr/lib/hpux32/libsdp.so

NOTE: By default, all the connections use SDP protocol because the libsdp.conf file has use sdp server * *:* and use sdp client * *:* lines.

Environment variables for SDP integration

For the transparent integration of applications with SDP, the following two environment variables are required:

•LD_PRELOAD—This environment variable is used to preload the libsdp.so library. The variable must point to the libsdp.so library. It is set to the libsdp.so library by the system administrator:

# export LD_PRELOAD=/usr/lib/hpux32/libsdp.so

•LIBSDP_CONFIG_FILE—This environment variable is used to configure the policy for replacing TCP sockets with SDP sockets. By default, it points to the /etc/libsdp.conf file.

Setting tunables

We can set the tunables using kctune(1M). SDP supports the following tunables:

sdp_rcvbuf_initial_size

This tunable sets the initial size of receive buffers in bytes.

sdp_retry_count

This tunable specifies the number of retries by the IB layer

 

when it fails to connect to the remote node.

sdp_recv_poll

This tunable specifies the number of seconds SDP should poll

 

the completion queue. CQ polling is stopped when at least

 

one poll is successful. The poll is specified in milliseconds.

sdp_disable_nagle

This tunable is used to disable the nagle algorithm. It affects

 

all the sockets running in the system. Thereafter, small packets

 

are sent immediately without any delay.

Environment variables for SDP integration

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