F5 is upgrading its customer support chat feature on My.F5.com. Chat support will be unavailable from 6am-10am PST on 1/20/26. Refer to K000159584 for details.

Forum Discussion

LoveNoodles's avatar
LoveNoodles
Icon for Altocumulus rankAltocumulus
Feb 02, 2019

equals vs eq?

Hi, is there any documentation or articles out there that suggest using "equals" is more efficient than using "eq" in string comparisons in irules?  
application delivery
iRules
Lee_Sutcliffe's avatar
Lee_Sutcliffe
Icon for Nacreous rankNacreous
Feb 03, 2019

It's worth noting that 'equals' is an iRule extension to TCL, whereas 'eq' is native TCL. Most iRule extensions such as 'starts_with' 'contains' 'not' etc have been added to make code easier to read.

Details of iRule operator expressions can be found in the Wiki https://devcentral.f5.com/wiki/iRules.Operators.ashx

Jason Rahm wrote an article a couple of months ago: Choose Your Operator Wisely

In it he compares 'starts_with' (iRule extension) and string match (native TCL). The native TCL command resulted in a 4.6% CPU saving.

I would probably always lean towards native TCL commands being quicker as anything else has been added on top - That said, like other answers have suggested, using the timing feature may help gauge a more accurate answer.