[Bug 503138] [NEW] after kernel message hrtimer: interrupt too slow.... the SMP(!) kvm guest becomes slow.

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KVM Host is running a clean 9.10 server install with just qemu-kvm and virt-manager kernel=2.6.31-17-generic
uname -a: Linux VMMASTER 2.6.31-17-generic #54-Ubuntu SMP Thu Dec 10 16:20:31 UTC 2009 i686 GNU/Linux
version signature: Ubuntu 2.6.31-17.54-generic

KVM Guest is running a clean 9.10 server install with some userland services (apache/postfix/whatnot) kernel=2.6.31-16-generic-pae (from the linux-image-virtual package)
uname -a: Linux VM1 2.6.31-16-generic-pae #53-Ubuntu SMP Tue Dec 8 05:20:21 UTC 2009 i686 GNU/Linux
version signature: Ubuntu 2.6.31-16.53-generic-pae

KVM guest startup command (as invoked by virt-manager):
/usr/bin/kvm -S -M pc-0.11 -m 1024 -smp 2 -name lexx -uuid [UUID] -monitor unix:/var/run/libvirt/qemu/VM1.monitor,server,nowait -boot c -drive file=,if=ide,media=cdrom,index=2 -drive file=/var/lib/libvirt/images/VM1.img,if=virtio,index=0,boot=on -net nic,macaddr=[MAC],vlan=0,model=virtio,name=virtio.0 -net tap,fd=16,vlan=0,name=tap.0 -serial none -parallel none -usb -vnc 127.0.0.1:0 -k en-us -vga cirrus

Problem description:

After a while (and high network IO) I see this pop up in my guest dmesg:
  hrtimer: interrupt too slow, forcing clock min delta to 215997540 ns
after that the guest becomes very slow to respond, sometimes taking seconds to echo my ssh input back, on a local lan. Only a reboot of the kvm guest fixes this, until the dreaded hrtimer message pops up 

After a lot of googling and trying a lot of things I found this discussion on the patchwork kernel mailinglist, which contains a possible solution:
http://patchwork.kernel.org/patch/51561/

Please look into it, perhaps this solves a lot of kvm-users' problems

I'd like to patch my kvm guests' kernel myself to test this hrtimer
patch, do you have the correct procedure for me so i can create a custom
kernel?

** Affects: kvm (Ubuntu)
     Importance: Medium
         Status: Triaged


** Tags: kernel-series-unknown patch
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after kernel message  hrtimer: interrupt too slow.... the SMP(!) kvm guest becomes slow.
https://bugs.launchpad.net/bugs/503138
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