High CPU in some TSS modules calling the ICSF CSNBOWH SHA-1 hashing function

Document ID : KB000015086
Last Modified Date : 14/02/2018
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Introduction:

High CPU in some TSS modules calling the ICSF CSNBOWH SHA-1 hashing function

Question:

High CPU in some TSS modules calling the ICSF CSNBOWH SHA-1 hashing function.

 

While running a new COBOL program that calculates SHA-1 hashes using the ICSF CSNBOWH service, it has been noted 

that the job uses a larger than expected amount of CPU resource. 

Further investigation has revealed that a large large portion of the CPU consumed by the job is used by various 

TSS modules such as TSSMVS2, SAFRT001 and TSSSFRVT. Is there a reason for this?

Environment:
z/os
Answer:

SSMVS2 and TSSSFRVT are load modules that contain a number of TSS modules. 

SAFRT001 is the module that issues a STORAGE OBTAIN at the beginning of every 

RACROUTE macro that is issued. Modules in TSSSFRVT and TSSMVS2 (most likely TSSRSVCS which processes all RACROUTE macros) 

are subsequently called. 

This looks like there are many RACROUTE authorization checks being issued as a result of invoking the CSNBOWH service.