Hi Everyone,
The significant performance degradation in ubuntu 12.04 in work with 9p file system. It is working only for a couple of hours under intesive read/write operations. after this all operations stops. The system required complete shutdown of qemu and restarting it. the bug is qemu because the host is working well and other virtual machines connected to the same folder works without any problems.
In my case this problem is reproducible: 3 times in a raw.
guest:~$ uname -a
Linux biouml-1 3.2.0-19-virtual #30-Ubuntu SMP Fri Mar 16 18:07:13 UTC 2012 x86_64 x86_64 x86_64 GNU/Linux
host:~$ uname -a
Linux s0 3.2.0-19-generic #30-Ubuntu SMP Fri Mar 16 16:27:15 UTC 2012 x86_64 x86_64 x86_64 GNU/Linux
kvm --version
QEMU emulator version 1.0 (qemu-kvm-1.0), Copyright (c) 2003-2008 Fabrice Bellard
VirtFS on /srv/shared type 9p (rw,trans=virtio,version=9p2000.L)
$ ps aux| grep kvm
one-52 -uuid 50994459-9e97-b488-2893-b4a75a65c559 -nodefconfig -nodefaults -chardev socket,id=charmonitor,path=/var/lib/libvirt/qemu/one-52.monitor,server,nowait -mon chardev=charmonitor,id=monitor,mode=control -rtc base=utc -no-shutdown -drive file=/var/lib/one/var//52/images/disk.0,if=none,id=drive-virtio-disk0,format=raw,cache=writeback -device virtio-blk-pci,bus=pci.0,addr=0x5,drive=drive-virtio-disk0,id=virtio-disk0,bootindex=1 -drive file=/var/lib/one/var//52/images/disk.1,if=none,id=drive-virtio-disk4,format=raw,cache=writeback -device virtio-blk-pci,bus=pci.0,addr=0x6,drive=drive-virtio-disk4,id=virtio-disk4 -fsdev local,security_model=mapped,id=fsdev-fs0,path=/tank/biouml-shared -device virtio-9p-pci,id=fs0,fsdev=fsdev-fs0,mount_tag=VirtFS,bus=pci.0,addr=0x3 -netdev tap,fd=18,id=hostnet0 -device virtio-net-pci,netdev=hostnet0,id=net0,mac=02:00:c0:a8:02:1e,bus=pci.0,addr=0x4 -usb -device usb-mouse,id=input0 -vnc 0.0.0.0:52 -vga cirrus -device virtio-balloon-pci,id=balloon0,bus=pci.0,addr=0x7 -cpu host
---
ApportVersion: 2.0-0ubuntu2
Architecture: amd64
DistroRelease: Ubuntu 12.04
InstallationMedia: Ubuntu-Server 11.10 "Oneiric Ocelot" - Release amd64 (20111011)
MachineType: Supermicro H8QG6
NonfreeKernelModules: zfs zcommon znvpair zavl zunicode
Package: qemu-kvm 1.0+noroms-0ubuntu10 [origin: Ubuntu]
PackageArchitecture: amd64
ProcKernelCmdLine: BOOT_IMAGE=/vmlinuz-3.2.0-21-generic root=UUID=39e3c519-7ef2-44ea-af9f-60f5328337f2 ro
ProcVersionSignature: Ubuntu 3.2.0-21.34-generic 3.2.13
Tags: precise third-party-packages
Uname: Linux 3.2.0-21-generic x86_64
UnreportableReason: This is not an official Ubuntu package. Please remove any third party package and try again.
UpgradeStatus: Upgraded to precise on 2012-03-15 (18 days ago)
UserGroups: adm admin cdrom dialout kvm libvirtd lpadmin plugdev sambashare
dmi.bios.date: 10/28/2011
dmi.bios.vendor: American Megatrends Inc.
dmi.bios.version: 2.0a
dmi.board.asset.tag: 1234567890
dmi.board.name: H8QG6
dmi.board.vendor: Supermicro
dmi.board.version: 1234567890
dmi.chassis.asset.tag: 1234567890
dmi.chassis.type: 17
dmi.chassis.vendor: Supermicro
dmi.chassis.version: 1234567890
dmi.modalias: dmi:bvnAmericanMegatrendsInc.:bvr2.0a:bd10/28/2011:svnSupermicro:pnH8QG6:pvr1234567890:rvnSupermicro:rnH8QG6:rvr1234567890:cvnSupermicro:ct17:cvr1234567890:
dmi.product.name: H8QG6
dmi.product.version: 1234567890
dmi.sys.vendor: Supermicro
Thanks for reporting this bug.
It sounds like a memory leak. I don't see any commits looking like 9pfs memory leaks upstream. Do you know if you can reproduce this with qemu.git?
Can you explain exactly how to reproduce this (i.e. how to exercise 9p)?