Thanks Arie for providing your configuration fix to the issue for anyone else being affected - that will be really helpful.
In that sense it is much more like bug 1346917 which was about KSM. Since the fix for that old bug they at least stopped being migrated around, but I can see how a lot of KSM based overcommit on remote nodes can make memory to be slow. But IMHO that is just one of the potential prices to pay with KSM, not that much of a bug but a configuration which happens to overload what the system can deliver. It needs a lot very slow memory to trigger the hrtimer issue, if you think there really is an issue to fix (other than the configuration) then I'd suggest try with the latest stack in Disco (19.04) which is very up to date in regard to kernel&qemu - if it still happens there you might report that upstream to the kernel ML - maybe there is an idea how to improve MM to cause less issues, but I'd expect they say that is what the tunable is for. But as said, if you report that to us as well - maybe once a patch exists to backport - I'd appreciate if that would be in a new bug. -- You received this bug notification because you are a member of Kernel Packages, which is subscribed to linux in Ubuntu. https://bugs.launchpad.net/bugs/503138 Title: Lucid & Natty, KVM, After kernel message hrtimer: interrupt too slow.... the SMP kvm guest becomes slow. Status in linux package in Ubuntu: Incomplete Status in qemu package in Ubuntu: Incomplete Bug description: 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? To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/503138/+subscriptions -- Mailing list: https://launchpad.net/~kernel-packages Post to : kernel-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~kernel-packages More help : https://help.launchpad.net/ListHelp
