Bug 1029343
| Summary: | irqbalance is broken in guest | ||
|---|---|---|---|
| Product: | Red Hat Enterprise Linux 6 | Reporter: | Chao Yang <chayang> |
| Component: | qemu-kvm | Assignee: | Radim Krčmář <rkrcmar> |
| Status: | CLOSED DUPLICATE | QA Contact: | Virtualization Bugs <virt-bugs> |
| Severity: | medium | Docs Contact: | |
| Priority: | medium | ||
| Version: | 6.6 | CC: | acathrow, alex.williamson, bsarathy, drjones, juzhang, michen, mkenneth, qzhang, rkrcmar, virt-maint |
| Target Milestone: | rc | ||
| Target Release: | --- | ||
| Hardware: | Unspecified | ||
| OS: | Unspecified | ||
| Whiteboard: | |||
| Fixed In Version: | Doc Type: | Bug Fix | |
| Doc Text: | Story Points: | --- | |
| Clone Of: | Environment: | ||
| Last Closed: | 2013-11-28 18:23:55 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: | |||
Reproducible with 6.4.Z kernel and qemu-kvm as well as rhel6.5 guest. 2.6.32-358.18.1.el6.x86_64 qemu-kvm-rhev-0.12.1.2-2.355.el6_4.9.x86_64 One interrupt can't be balanced across multiple cpus with '-cpu host', because it selects physical x2apic at this time. (nox2apic kernel parameter also works) irqbalance then can't do much with just one interrupt source -- moving it to another cpu is not making anything better. But there is a deficiency in irqbalance that the reporter might have meant: even with priority balancing, irqbalance still sets smp_affinity to just one cpu, although we could achieve better balance if it considered wider masks. This is expected, for reasons in comment #3; see the parent bug for behavior details. *** This bug has been marked as a duplicate of bug 960383 *** |
Description of problem: Booted a guest with virtio-net-pci, started irqbalance in debug mode. Stressed virtio nic by netperf. What I observed is the corresponding interrupt was distributed consistently on the 2nd vCPU. Version-Release number of selected component (if applicable): 2.6.32-430.el6.x86_64 qemu-kvm-0.12.1.2-2.415.el6.x86_64 How reproducible: 100% Steps to Reproduce: 1. 2. 3. Actual results: Expected results: Additional info: CLI: /usr/libexec/qemu-kvm -M rhel6.5.0 -cpu host -enable-kvm -m 4096 -realtime mlock=off -smp 4,sockets=2,cores=2,threads=1 -nodefaults -monitor stdio -boot menu=on -rtc base=utc,clock=host,driftfix=slew -device piix3-usb-uhci,id=usb,bus=pci.0,addr=0x1.0x2 -device virtio-serial-pci,id=virtio-serial0,bus=pci.0 -drive file=/home/rhel6.5.qcow2,if=none,id=drive-virtio-disk0,format=qcow2,cache=none,werror=stop,rerror=stop,aio=native -device virtio-blk-pci,scsi=off,bus=pci.0,drive=drive-virtio-disk0,id=virtio-disk0,bootindex=1 -netdev tap,id=hostnet0,vhost=on -device virtio-net-pci,netdev=hostnet0,id=net0,mac=46:1a:4a:42:48:25,bus=pci.0 -k en-us -vga cirrus -device intel-hda,id=sound0,bus=pci.0 -device hda-duplex,id=sound0-codec0,bus=sound0.0,cad=0 -device virtio-balloon-pci,id=balloon0,bus=pci.0 -vnc :1 -- In guest: # lspci | grep Eth 00:05.0 Ethernet controller: Red Hat, Inc Virtio network device # dmesg | grep 00:05.0 pci 0000:00:05.0: reg 10: [io 0xc0c0-0xc0df] pci 0000:00:05.0: reg 14: [mem 0xf2022000-0xf2022fff] pci 0000:00:05.0: reg 30: [mem 0xf2030000-0xf203ffff pref] virtio-pci 0000:00:05.0: PCI INT A -> Link[LNKA] -> GSI 10 (level, high) -> IRQ 10 virtio-pci 0000:00:05.0: irq 28 for MSI/MSI-X virtio-pci 0000:00:05.0: irq 29 for MSI/MSI-X virtio-pci 0000:00:05.0: irq 30 for MSI/MSI-X -- A snip from output of irqbalance in guest: ---------------------------------------------------------------------------- Package 0: numa_node is 0 cpu mask is 00000003 (load 0) Cache domain 0: numa_node is 0 cpu mask is 00000001 (load 0) CPU number 0 numa_node is 0 (load 0) Interrupt 30 node_num is -1 (ethernet/1) Interrupt 25 node_num is -1 (storage/1) Cache domain 1: numa_node is 0 cpu mask is 00000002 (load 0) CPU number 1 numa_node is 0 (load 0) Interrupt 28 node_num is -1 (ethernet/1) Interrupt 11 node_num is -1 (legacy/1) Interrupt 26 node_num is -1 (other/1) Package 0: numa_node is 0 cpu mask is 0000000c (load 13000) Cache domain 2: numa_node is 0 cpu mask is 00000004 (load 26000) CPU number 2 numa_node is 0 (load 26000) Interrupt 29 node_num is -1 (ethernet/1) Interrupt 9 node_num is -1 (legacy/1) Cache domain 3: numa_node is 0 cpu mask is 00000008 (load 0) CPU number 3 numa_node is 0 (load 0) Interrupt 24 node_num is -1 (storage/1) Interrupt 10 node_num is -1 (other/1) Interrupt 27 node_num is -1 (other/1) ----------------------------------------------------------------------------- Package 0: numa_node is 0 cpu mask is 00000003 (load 0) Cache domain 0: numa_node is 0 cpu mask is 00000001 (load 0) CPU number 0 numa_node is 0 (load 0) Interrupt 30 node_num is -1 (ethernet/1) Interrupt 25 node_num is -1 (storage/1) Cache domain 1: numa_node is 0 cpu mask is 00000002 (load 0) CPU number 1 numa_node is 0 (load 0) Interrupt 28 node_num is -1 (ethernet/1) Interrupt 11 node_num is -1 (legacy/1) Interrupt 26 node_num is -1 (other/1) Package 0: numa_node is 0 cpu mask is 0000000c (load 16500) Cache domain 2: numa_node is 0 cpu mask is 00000004 (load 33000) CPU number 2 numa_node is 0 (load 33000) Interrupt 29 node_num is -1 (ethernet/1) Interrupt 9 node_num is -1 (legacy/1) Cache domain 3: numa_node is 0 cpu mask is 00000008 (load 0) CPU number 3 numa_node is 0 (load 0) Interrupt 24 node_num is -1 (storage/1) Interrupt 10 node_num is -1 (other/1) Interrupt 27 node_num is -1 (other/1) ----------------------------------------------------------------------------- Package 0: numa_node is 0 cpu mask is 00000003 (load 500) Cache domain 0: numa_node is 0 cpu mask is 00000001 (load 1000) CPU number 0 numa_node is 0 (load 1000) Interrupt 30 node_num is -1 (ethernet/750) Interrupt 25 node_num is -1 (storage/994) Cache domain 1: numa_node is 0 cpu mask is 00000002 (load 0) CPU number 1 numa_node is 0 (load 0) Interrupt 28 node_num is -1 (ethernet/1) Interrupt 11 node_num is -1 (legacy/1) Interrupt 26 node_num is -1 (other/1) Package 0: numa_node is 0 cpu mask is 0000000c (load 19000) Cache domain 2: numa_node is 0 cpu mask is 00000004 (load 38000) CPU number 2 numa_node is 0 (load 38000) Interrupt 29 node_num is -1 (ethernet/1) Interrupt 9 node_num is -1 (legacy/1) Cache domain 3: numa_node is 0 cpu mask is 00000008 (load 0) CPU number 3 numa_node is 0 (load 0) Interrupt 24 node_num is -1 (storage/1) Interrupt 10 node_num is -1 (other/1) Interrupt 27 node_num is -1 (other/1)