KVM: VMX: increase ple_gap default to 128
On some CPUs, a ple_gap of 41 is simply insufficient to ever trigger PLE exits, even with the minimalistic PLE test from kvm-unit-tests. http://git.kernel.org/?p=virt/kvm/kvm-unit-tests.git;a=commitdiff;h=eda71b28fa122203e316483b35f37aaacd42f545 For example, the Xeon X5670 CPU needs a ple_gap of at least 48 in order to get pause loop exits: # modprobe kvm_intel ple_gap=47 # taskset 1 /usr/local/bin/qemu-system-x86_64 \ -device testdev,chardev=log -chardev stdio,id=log \ -kernel x86/vmexit.flat -append ple-round-robin -smp 2 VNC server running on `::1:5900' enabling apic enabling apic ple-round-robin 58298446 # rmmod kvm_intel # modprobe kvm_intel ple_gap=48 # taskset 1 /usr/local/bin/qemu-system-x86_64 \ -device testdev,chardev=log -chardev stdio,id=log \ -kernel x86/vmexit.flat -append ple-round-robin -smp 2 VNC server running on `::1:5900' enabling apic enabling apic ple-round-robin 36616 Increase the ple_gap to 128 to be on the safe side. Signed-off-by:Rik van Riel <riel@redhat.com> Acked-by:
Zhai, Edwin <edwin.zhai@intel.com> Signed-off-by:
Avi Kivity <avi@redhat.com>
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3781c01c
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