Bug 851382

Summary: usage of cpu is 100% after boot up win7-64 guest with -m 192GB
Product: Red Hat Enterprise Linux 5 Reporter: FuXiangChun <xfu>
Component: kvmAssignee: Virtualization Maintenance <virt-maint>
Status: CLOSED WONTFIX QA Contact: Virtualization Bugs <virt-bugs>
Severity: medium Docs Contact:
Priority: unspecified    
Version: 5.9CC: chayang, flang, gleb, juzhang, michen, mkenneth, qzhang, rhod, shu, sluo, virt-maint, vrozenfe, wdai
Target Milestone: rc   
Target Release: ---   
Hardware: x86_64   
OS: Windows   
Whiteboard:
Fixed In Version: Doc Type: Bug Fix
Doc Text:
Story Points: ---
Clone Of: Environment:
Last Closed: 2013-04-10 13:53:01 UTC Type: Bug
Regression: --- Mount Type: ---
Documentation: --- CRM:
Verified Versions: Category: ---
oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
Embargoed:
Bug Depends On: 820112    
Bug Blocks:    
Attachments:
Description Flags
win7 screenshot none

Description FuXiangChun 2012-08-24 01:32:58 UTC 
Description of problem:
  win7-64 guest max support memory 192G. I attached a sreenshot. this is a testing matrix:

matrix

mem    cpu     connection    usage of vcpu
2G     >16     vnc or spice   20%
192   >=16     vnc or spice   100% 
192   <16      vnc or spice   100%


notes: host info
cpu:AMD Opteron(tm) Processor 6172
cpu cores: 48
MEM:512G


Version-Release number of selected component (if applicable):
# uname -r
2.6.18-336.el5
#rpm -qa|grep kvm
# uname -r
2.6.18-336.el5

How reproducible:
100%

Steps to Reproduce:
1./usr/libexec/qemu-kvm -m 192G -smp 16 -cpu qemu64,+sse2 -drive file=win7-64,format=qcow2,media=disk,if=virtio,boot=on,werror=stop -net nic,model=virtio,macaddr=04:16:37:51:37:27,vlan=0 -net tap,sndbuf=0,vlan=0,script=/etc/qemu-ifup,downscript=no -uuid 7e8fabbb-ce86-4b2c-8df7-841b4d3901a4 -vnc :1 -boot c -usbdevice tablet -no-hpet -rtc-td-hack -no-kvm-pit-reinjection -monitor stdio -balloon none
2.check usage of cpu in guest
3.
  
Actual results:
usage of cpu is 100%

Expected results:
usage of cpu is <30%

Additional info:
Comment 1 FuXiangChun 2012-08-24 01:35:41 UTC 
Created attachment 606729 [details]
win7 screenshot
Comment 2 FuXiangChun 2012-08-24 02:37:13 UTC 
Try to find specific memory value that cause guest useage of cpu 100%.

summuary:

Mem        cpu     duration(usage of cpu(100%)

80G        4cores  about 1 minute

90         4cores  about 5 minutes

128G       4cores  exceed 10minutes(unknow)

>128       4cores  unknow
Comment 3 Ronen Hod 2012-08-26 10:02:34 UTC 
For now, deferring to 5.10.
Probably we will never fix it.
Lets see what happens with the RHEL6 bug 820112 (also interesting is bug 844862).
Comment 4 FuXiangChun 2012-08-29 02:25:52 UTC 
There is the same issue on Intel host.