Your code may be the best design possible but it still uses CPU. Redesigning and rewriting code to be more efficient is not the point of zIIP processors. They are simply an IBM sales tool to make the price if z hardware more price competitive. Running code in zIIP is less efficient (code must be run in a special SRB) but it much cheaper to use than the standard CPU.
1. Specialty processors (zIIP, zAAP, IFL and others that IBM may implement) are general CP's. They physically do the same things as a GCP. 2. Prices for specialty processors are significantly cheaper than a GCP. IBM does not want customers to run everything on them. 3. To restrict customer usage of specialty processors, IBM must implement some method for restricting the use of a specialty processor. 4. For IFL (Linux processors), IBM disabled some instructions that are critical to z/OS, zVSE and zVM but never used by zLinux. This keeps customers from assigning IFL's to z/OS because it will fail. 5. IBM intends zIIP to be used for system related workload (system overhead). From their viewpoint, customers can easily justify paying for application CPU usage. Its far more difficult to justify and portion out system overhead. Customer charge various departments for their CPU usage. System overhead is difficult to portion because of it's nature. Long ago when I was involved in chargeback, we simply portioned database workload because we could not attribute specific amounts to a specific group. With zIIP, this workload becomes far less significant. 6. zIIP is first restricted by requiring programs run under an SRB. SRB's are a big security exposure so customers are unlikely to open them to their programmers. 7. To restrict software vendors, the SRB must run in a special enclave. Vendors must sign a non-disclosure agreement about this special enclave. I suspect that IBM includes some sort of usage clause in that agreement. Jon Perryman >________________________________ > From: Scott Ford <[email protected]> > > >After reading this thread, I understand the need for zIIP processors for heavy >CPU processes, but what about resigning and rewriting these applications ? For >us, who learned assembler or BAL ...we had less to use , cycle wise and >storage, but still managed to develop good code. > > ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN
