Thanks Víctor Echavarry System Programmer Technology Systems & Operations Division EVERTEC
-----Original Message----- From: Linux on 390 Port [mailto:[email protected]] On Behalf Of Michael O'Reilly Sent: Wednesday, April 07, 2010 11:15 AM To: [email protected] Subject: Re: Add additional CPU Victor, I have the following notes: How to dynamically add a CPU to an already logged on z/VM guest. Traditionally, additional CPUs are defined using a USER DIRECT "CPU" statement, which requires a guest logoff/logon and IPL to utilize. One can dynamically increase the number of CPUs from the number of CPU statements to the maximum specified in the USER DIRECT "MACHINE" statement. If a guest has the following statements in USER DIRECT: MACHINE ESA 3 CPU 00 BASE CPU 01 They can use the CP commands to define and start a 3rd CPU. # vmcp query virtual cpus CPU 00 ID FF04920020640000 (BASE) CP CPUAFF ON CPU 01 ID FF04920020640000 CP CPUAFF ON # vmcp define cpu 02 CPU 02 defined # vmcp query virtual cpus CPU 00 ID FF04920020640000 (BASE) CP CPUAFF ON CPU 01 ID FF04920020640000 CP CPUAFF ON CPU 02 ID FF04920020640000 STOPPED CP CPUAFF ON # vmcp begin cpu 02 # vmcp query virtual cpus CPU 00 ID FF04920020640000 (BASE) CP CPUAFF ON CPU 01 ID FF04920020640000 CP CPUAFF ON CPU 02 ID FF04920020640000 CP CPUAFF ON Linux will still not be able to use the CPUs, until the sysfs structures are allocated. At boot time, that's done for the CPUs available. In sles9 the default is to preallocate all 64 sysfs CPU structures. One could online them when new CPUs are added. # echo 1 > /sys/devices/system/cpu/cpu2/online In sles10 a kernel/zipl parameter called: "possible_cpus" is available. So if one had, for example, possible_cpus=8 in zipl, there would be sysfs structures for eight CPUs from the beginning and you could online them when new CPUs are added to the LPAR and z/VM. This may still require a new reboot in sles10, if this had not been done. A SLES11 example: # vmcp query virtual cpus CPU 00 ID FF04920020640000 (BASE) CP CPUAFF ON # vmcp define cpu 01 CPU 01 defined # vmcp query virtual cpus CPU 00 ID FF04920020640000 (BASE) CP CPUAFF ON CPU 01 ID FF04920020640000 STOPPED CP CPUAFF ON # ls /sys/devices/system/cpu/ cpu0 dispatching online possible present rescan sched_mc_power_savings # echo 1 > /sys/devices/system/cpu/rescan # ls /sys/devices/system/cpu/ cpu0 cpu1 dispatching online possible present rescan sched_mc_power_savings # echo 1 > /sys/devices/system/cpu/cpu1/online # vmcp query virtual cpus CPU 00 ID FF04920020640000 (BASE) CP CPUAFF ON CPU 01 ID FF04920020640000 CP CPUAFF ON # cat /proc/cpuinfo vendor_id : IBM/S390 # processors : 2 bogomips per cpu: 2693.00 features : esan3 zarch processor 0: version = FF, identification = 049200, machine = 2064 processor 1: version = FF, identification = 049200, machine = 2064 To deactivate an operating CPU: Bring the CPU offline by writing "0" to its online attribute: # echo 0 > /sys/devices/system/cpu/cpu1/online # vmcp query virtual cpus CPU 00 ID FF04920020640000 (BASE) CP CPUAFF ON CPU 01 ID FF04920020640000 STOPPED CP CPUAFF ON # grep processor /proc/cpuinfo # processors : 1 processor 0: version = FF, identification = 049200, machine = 2064 There is no way to remove a STOPPED CPU without a Guest reset and no need to as only a few z/VM control blocks remain for the Virtual CPU. ________________________ Mike O'Reilly IBM Linux Change Team Victor Echavarry Diaz <vechava...@evert To ecinc.com> [email protected] Sent by: Linux on cc 390 Port <[email protected] Subject ist.edu> Add additional CPU 04/07/2010 07:05 AM Please respond to Linux on 390 Port <[email protected] ist.edu> Is there a way to add an additional CPU to a Linux guest without shutting down? Regards, Víctor Echavarry System Programmer Technology Systems & Operations Division EVERTEC ----------------------------------------- CONFIDENTIALITY NOTE: This email communication and its attachments contain information that are proprietary and confidential to EVERTEC, INC., its affiliates or its clients. They may not be disclosed, distributed, used, copied or modified in any way without EVERTEC, Inc.’s authorization. If you are not the intended recipient of this email, you are not an authorized person. Please delete it and notify the sender immediately. EVERTEC, Inc. and its affiliates do not assume any liability for damages resulting from emails that have been sent or altered without their consent. 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