previous post http://www.garlic.com/~lynn/2007c.html#47 SVCs
... and old email on dispatching "disabled" from long ago and far away To: wheeler Date: 21 January 1986, 07:11:46 CST Subject: Dispatcher change for VM/XA I am planning on changing the XA dispatcher to execute the SIE instruction with I/O interrupts disabled (external interrupts will still be enabled). The SIE instruction is a very expensive instruction and I want to give the virtual machine a chance to do some productive work before taking an interrupt. With I/O interrupts disabled, the virtual machine will get to run until it relinquishes control to CP or hits the end of the dispatcher timeslice. The I/O supervisor already uses the TPI instruction to process all pending interrupts before returning control to the dispatcher. Do you have any thoughts on the matter? I have read CPDESIGN FORUM on the IBMVM disk, so I know what has been discussed there. Do you have a ballpark figure for the maximum allowable dispatcher timeslice which would allow satisfactory I/O throughput? I am thinking about disabling I/O interrupts for a maximum of 10 milliseconds. Another alternative would be to have DMKSTP set/reset the interrupt mask based upon the observed I/O interrupt rate. ... snip ... i.e. some amount of the stuff in the original vm370 resource manager got modified in unusual ways over extended period of time (i.e from decade earlier that above email) misc. collected posts mentioning resource manager, dynamic adaptive resource control, fair share, etc http://www.garlic.com/~lynn/subtopic.html#fairshare previous post http://www.garlic.com/~lynn/2006j.html#27 virtual memory with old email discussing SIE implementation differences between 3081 and 3090 in some detail http://www.garlic.com/~lynn/2006j.html#email810630 ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [EMAIL PROTECTED] with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html
