On Wednesday, 11/09/2005 at 01:06 CST, James Melin <[EMAIL PROTECTED]> wrote: > I spoke to an IBM expert on things WebSphere on z/Series and he had this to > say:
>> You will experience much degraded performance when you are running Linux >> under VM under VM. My understanding of this is that it is caused by running >> the SIE (start interpretive execution) hardware instruction in software. VM >> uses the SIE instruction to run guest operating systems like Linux. When VM >> is itself running interpreted (2nd-level) then when it uses the SIE to run >> Linux that SIE is running in software emulation. Careful! This was on a 2064 (z900). If it was running in LPAR mode, the above is true. In native mode, the 2nd level CP has access to SIE. (From the description, it sounds like it was in LPAR mode.) > Any way to prevent third level guests from doing SIE in emulation? SIE is not emulated. The SIE "pancakes" down to a level that has real SIE. But the timeslice is very very tiny and the resident pages of the guest are few. 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
