[Bug 42755] New: KVM is being extremely slow on AMD Athlon64 4000+ Dual Core 2.1GHz Brisbane

[bugzilla-daemon@bugzilla.kernel.org]

https://bugzilla.kernel.org/show_bug.cgi?id=42755

           Summary: KVM is being extremely slow on AMD Athlon64 4000+ Dual
                    Core 2.1GHz Brisbane
           Product: Virtualization
           Version: unspecified
    Kernel Version: 3.2.2
          Platform: All
        OS/Version: Linux
              Tree: Mainline
            Status: NEW
          Severity: normal
          Priority: P1
         Component: kvm
        AssignedTo: virtualization_kvm@kernel-bugs.osdl.org
        ReportedBy: sandikata@yandex.ru
        Regression: No


Hello.

Kvm seems to be broken on AMD Athlon64 4000+ Dual Core 2.1GHz Brisbane. A
kernel build takes over
2 hours, compared to 15 minutes on the host. I'm running with virtio
for storage, and this does not seem to be related to IO. A simple test
with dd also demonstrates that the problem is cpu-ralated:

Host test:
dd if=/dev/zero of=/dev/null bs=1k count=8M
8388608+0 записей считано (read)
8388608+0 записей написано (write)
 скопировано (copyed) 8589934592 байта (8,6 GB), 7,04456 c, 1,2 GB/c

This also does not seem to be a cpu bug, as both VirtualBox and VMware
work fine.

Vmware/Virtualbox test:
dd if=/dev/zero of=/dev/null bs=1k count=8M
8388608+0 записей считано (read)
8388608+0 записей написано (write)
 скопировано (copyed) 8589934592 байта (8,6 GB), 5,02745 c, 1,7 GB/c

I've tried different kernels on host, between 2.6.22 and current git,
with the same results. The guest is running Gentoo Hardened kernel 3.2.2
, but I could try with a an other distro and a vanilla kernel
if required.

My kvm version is kvm 1.0

Help would be much appreciated.

-- 
Configure bugmail: https://bugzilla.kernel.org/userprefs.cgi?tab=email
------- You are receiving this mail because: -------
You are watching the assignee of the bug.