Bug 547410

Summary: guest cpu stuck for 10s when guest is loaded
Product: Red Hat Enterprise Linux 5 Reporter: lihuang <lihuang>
Component: kvmAssignee: Kevin Wolf <kwolf>
Status: CLOSED WONTFIX QA Contact: Virtualization Bugs <virt-bugs>
Severity: medium Docs Contact:
Priority: low    
Version: 5.4CC: llim, ovirt-maint, tburke, virt-maint, ykaul
Target Milestone: rc   
Target Release: ---   
Hardware: All   
OS: Linux   
Whiteboard:
Fixed In Version: Doc Type: Bug Fix
Doc Text:
Story Points: ---
Clone Of: Environment:
Last Closed: 2010-12-01 14:51:01 UTC Type: ---
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:    
Bug Blocks: 580948    
Attachments:
Description Flags
call trace in guest none

Description lihuang 2009-12-14 16:03:56 UTC
Created attachment 378255 [details]
call trace in guest

Description of problem:
1. found calltrace in guest(attached is the log), I met the calltrace twice. one is when scp a large file(3.4G) from a remote machine to the guest. another one is when running iozone test inside guest.

2. nothing interesting in host was found.

3. the image files are on remote nfs server.

4. CLI:
qemu-kvm CLI :/usr/libexec/qemu-kvm -m 2048 -smp 2 -drive file=/data/images/t78/images/ChenZhou/5.4-64.virtio.virtio.qcow2.20,if=virtio,boot=on,cache=off -drive file=/data/images/t78/images/test2.qcow2.64k,if=virtio,cache=off -drive file=/data/images/t195/images/test1.qcow2.4k,if=virtio,cache=off -net nic -net tap -vnc :2 -monitor stdio -usbdevice tablet -uuid c3105705-6c51-40b5-80eb-a0ffa387575a

iozone CLI  :./iozone -aZR -n 16g -g 22g -y 32k -q 64k -M -b /root/result.xls -f /mnt/1/testfile

5. guest is RHEL5.4 X86_64






Version-Release number of selected component (if applicable):

Red Hat Enterprise Virtualization Hypervisor release 5.4-2.1 (2)
kvm-83-105.el5_4.13
kernel-2.6.18-164.8.1.el5


How reproducible:
reproduce twice so far

Steps to Reproduce:
1.
2.
3.
  
Actual results:


Expected results:


Additional info:

Comment 1 Dor Laor 2010-01-20 09:32:01 UTC
I'm not sure this is a bug, it might be due too stall by synchronous first time allocation done by qcow2.

Can you first fully populate the guest image by writing to the entire disk and afterwards erase these dummy files and return the test again?

Comment 2 lihuang 2010-01-27 11:11:25 UTC
(In reply to comment #1)
> I'm not sure this is a bug, it might be due too stall by synchronous first time
> allocation done by qcow2.
> 
> Can you first fully populate the guest image by writing to the entire disk and
> afterwards erase these dummy files and return the test again?    

Yes. test 3 times,only reproduce when writing a fresh disk.