SAV Dynamic Interface user manual
5 Appendix: SAV Dynamic Interface Performance
The method used by the client to interact with the SAV Dynamic Interface will be constrained by circumstances. Nonetheless the following are offered as guidelines in selecting the best method:
■
Connect and stay connected. There is a considerable overhead to establishing the connection, and breaking it.
■
Use a Unix domain socket, or windows named pipe rather than TCP/IP. There is an extra overhead using TCP/IP.
■
Avoid using a one-off script, i.e. executing a script for each scan. Not only is there the overhead of making a new connection but also the overhead of starting the interpreter, script compilation, and so on.
■
Use the SSSP OPTIONS request only if necessary, it is cheaper to have the options set in the configuration file. If a client has different needs to other clients, create another channel tailored for that client.
■
If possible scan a whole directory rather than making requests to scan each file.
To illustrate the differences in performance, the following table, ordered with the fastest first, shows throughput of files being scanned relative to the fastest method (indexed at 100):
1. A C program which connects, scans a file 100 times, and disconnects is run once.
Option
Unix domain socket
TCP/IP (localhost:4010)
Value
100
97
2. A Perl script which connects, scans a file 100 times, and disconnects is run once.
Option
Unix domain socket
TCP/IP (localhost:4010)
Value
83
81
3. A Perl script which connects, scans a file, and disconnects 100 times is run once.
Option
Unix domain socket
TCP/IP (localhost:4010)
Value
56
50
27
SAV Interface Developer Toolkit
4. A C program which connects, scans a file, and disconnects is run 100 times.
Option
Unix domain socket
TCP/IP (localhost:4010)
Value
17
6
5. A Perl script which connects, scans a file, and disconnects is run 100 times.
Option
Unix domain socket
TCP/IP (localhost:4010)
Value
4
3
28
