Riverbed iRule Performance

Hi Frischi,

the [STREAM] and also [HTTP::payload] commands are both rather expensive. The total performance impact does strongly depend on your traffic rate and also mix of requested content...

Some additional thoughts on your code...

• It would save some cycles to include the $stream_find patter directly to $static::OPNET_jscript. Create two $static:: variables if CASE is that important for you.
• You may have to remove the Accept-Encoding headers during HTTP_REQUEST in order to make [STREAM] able to parse otherwise compressed content. And you may want to selectivly compress the content on LTM, before sending to clients.
• To support keep-alive connections you should disable [STREAM] for every not matching response.
• I duno what type of script you're going to inject into your HTML sites. But how about injecting the code just to err200 and mime-type text/html. It would make things lot easier...
• I would filter content-type=text/html (matches less % of total request) before err200 for performance reasons.
• The [HTTP::payload] contains "META HTTP-EQUIV command can't be called without the [HTTP::collect] command.
• Investigate if a location change of your JScript is possible (e.g. right before or even ). This change may allow you to use STREAM_MATCH events for the META HTTP-EQUIV exception. I guess it would be much better to use [STREAM] only.
• Didn't know that a [STREAM::expression] command can be called multiple times to create expression lists. Does it really work out?
• Try to avoid variables as much as possible. (e.g. $insertJscript, $stream_find and $stream_find_lower can be avoided)

Cheers, Kai