Red Hat Bugzilla – Bug 1495456
Update downstream qemu's max supported cpus for pseries to the RHEL supported number
Last modified: 2018-04-10 20:37:50 EDT
Description of problem: Need to adjust the max cpus supported number from error message since it was conflict with KVM's Version-Release number of selected component (if applicable): kernel-4.11.0-36.el7a.ppc64le qemu-kvm-2.9.0-23.el7a.ppc64le SLOF-20170303-4.git66d250e.el7.noarch How reproducible: 3/3 Steps to Reproduce: 1.boot up with "-smp 64,maxcpus=102464,cores=8,threads=1,sockets=8 " qemu-kvm: Number of SMP CPUs requested (102464) exceeds max CPUs supported by machine 'pseries-rhel7.4.0alt' (1024) 2.according to the above message "-m 6G,maxmem=300G,slots=256 -smp 64,maxcpus=1024,cores=8,threads=1,sockets=128" Warning: Number of hotpluggable cpus requested (1024) exceeds the recommended cpus supported by KVM (176) Number of hotpluggable cpus requested (1024) exceeds the maximum cpus supported by KVM (240) 3. Actual results: It seemed that 1024 was useless since KVM only support 240 so far. Expected results: Perhaps,we need to adjust it to an reasonable value 240 or something else if possible. Additional info:
Essentially cosmetic, postponing to RHEL7.5.
Brewed a qemu with the correct value at: https://brewweb.engineering.redhat.com/brew/taskinfo?taskID=14661947 Still need to fix up the KVM side.
------- Comment From sthoufee@in.ibm.com 2017-12-01 05:17 EDT------- I had found the area of code failure. Will post the patch soon.. So with the patch , when boot up with it would expected to show the below message qemu-system-ppc64: Invalid SMP CPUs 102464. The max CPUs supported by machine 'pseries-rhel7.4.0alt' is 240
oops ... the previous comment has to read: " I had found the area of code failure. Will post the patch soon.. So with the patch , when boot up with "-smp 64,maxcpus=102464,cores=8,threads=1,sockets=8 " qemu-kvm: Number of SMP CPUs requested (102464) exceeds max CPUs supported by machine 'pseries-rhel7.4.0alt' (1024) it would expected to show the below message qemu-system-ppc64: Invalid SMP CPUs 102464. The max CPUs supported by machine 'pseries-rhel7.4.0alt' is 240 " ...
------- Comment From sthoufee@in.ibm.com 2017-12-01 06:27 EDT------- Patch posted for review. Awaiting response.
Downstream only fix posted. As noted in the notes for that patch, using the maximum number of vcpus (384) requires threads=2 or greater. Min, can you file a different bug to track the case of -smp 384,threads=1
For reference, the increase to 384 vCPUs on x86 was added via Bug 1433956.
Fix included in qemu-kvm-rhev-2.10.0-11.el7
Reproduce the issue on old version: Version-Release number of selected component (if applicable): qemu-kvm-rhev-2.10.0-10.el7.ppc64le Steps to Reproduce: 1.boot up with "-smp 64,maxcpus=102464,cores=8,threads=1,sockets=8 " qemu-kvm: Invalid SMP CPUs 102464. The max CPUs supported by machine 'pseries-rhel7.5.0' is 1024 2.according to the above message "-smp 64,maxcpus=1024,cores=8,threads=1,sockets=128" Warning: Number of hotpluggable cpus requested (1024) exceeds the recommended cpus supported by KVM (144) Number of hotpluggable cpus requested (1024) exceeds the maximum cpus supported by KVM (240) Verified the issue on the latest build: Version-Release number of selected component (if applicable): qemu-kvm-rhev-2.10.0-11.el7.ppc64le Steps to Reproduce: 1.The same steps as above Actual results: 1.qemu-kvm: Invalid SMP CPUs 102464. The max CPUs supported by machine 'pseries-rhel7.5.0' is 384 2.qemu-kvm: Invalid SMP CPUs 1024. The max CPUs supported by machine 'pseries-rhel7.5.0' is 384
Since the problem described in this bug report should be resolved in a recent advisory, it has been closed with a resolution of ERRATA. For information on the advisory, and where to find the updated files, follow the link below. If the solution does not work for you, open a new bug report. https://access.redhat.com/errata/RHSA-2018:1104