On Thursday, 11/17/2005 at 11:51 EST, Doug Carroll <[EMAIL PROTECTED]> wrote: > Yes, This was brought up in a recent lab/class in Poughkeepsie. > Currently under VM including VM 5.2 being released this constraint still > exists. the SIE instruction as stated is being emulated in software in a > second level VM system. I think Denise said they where working on > improving this but currently and in 5.2 you will see degration in > performance and we did witness it in the class.
This is not quite correct. There is no simulation or emulation of the SIE instruction. If a guest issues SIE and the Interpretive Execution Facility is not available, CP will "reshape" the guest's SIE instruction such that it can be issued by CP on the guest's behalf. The "Pancake Effect" (as I call it) continues until the Facility is available and the SIE instruction runs in hardware. This is an issue with hardware, not software. Alan Altmark z/VM Development IBM Endicott ---------------------------------------------------------------------- For LINUX-390 subscribe / signoff / archive access instructions, send email to [EMAIL PROTECTED] with the message: INFO LINUX-390 or visit http://www.marist.edu/htbin/wlvindex?LINUX-390
