From: Waiman Long <longman@redhat.com>
To: Eduardo Habkost <ehabkost@redhat.com>,
Paolo Bonzini <pbonzini@redhat.com>
Cc: qemu-devel@nongnu.org, "Michael S. Tsirkin" <mst@redhat.com>,
Igor Mammedov <imammedo@redhat.com>,
Davidlohr Bueso <dave@stgolabs.net>,
libvir-list@redhat.com
Subject: Re: [Qemu-devel] [PATCH 0/7] x86: Rework KVM-defaults compat code, enable kvm_pv_unhalt by default
Date: Tue, 10 Oct 2017 14:07:25 -0400 [thread overview]
Message-ID: <4b9e65ed-3636-bff4-3cca-52f6b80bca3b@redhat.com> (raw)
In-Reply-To: <20171010155003.GD3246@localhost.localdomain>
On 10/10/2017 11:50 AM, Eduardo Habkost wrote:
>> Yes. Another possibility is to enable it when there is >1 NUMA node in
>> the guest. We generally don't do this kind of magic but higher layers
>> (oVirt/OpenStack) do.
> Can't the guest make this decision, instead of the host?
By guest, do you mean the guest OS itself or the admin of the guest VM?
I am thinking about maybe adding kernel boot command line option like
"unfair_pvspinlock_cpu_threshold=4" which will instruct the OS to use
unfair spinlock if the number of CPUs is 4 or less, for example. The
default value of 0 will have the same behavior as it is today. Please
let me know what you guys think about that.
Cheers,
Longman
next prev parent reply other threads:[~2017-10-10 18:07 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-10-06 21:52 [Qemu-devel] [PATCH 0/7] x86: Rework KVM-defaults compat code, enable kvm_pv_unhalt by default Eduardo Habkost
2017-10-06 21:52 ` [Qemu-devel] [PATCH 1/7] qemu-doc: Document minimum kernel version for KVM in x86_64 Eduardo Habkost
2017-10-09 13:40 ` Paolo Bonzini
2017-10-10 15:33 ` Eduardo Habkost
2017-10-06 21:52 ` [Qemu-devel] [PATCH 2/7] target/i386: x86_cpu_expand_feature() helper Eduardo Habkost
2017-10-06 21:52 ` [Qemu-devel] [PATCH 3/7] target/i386: Use global variables to control KVM defaults Eduardo Habkost
2017-10-06 21:52 ` [Qemu-devel] [PATCH 4/7] kvm: Define KVM_FEAT_* even if CONFIG_KVM is not defined Eduardo Habkost
2017-10-06 21:52 ` [Qemu-devel] [PATCH 5/7] target/i386: Handle kvm_auto_* compat in x86_cpu_expand_features() Eduardo Habkost
2017-10-06 21:52 ` [Qemu-devel] [PATCH 6/7] pc: Use compat_props to control KVM defaults compatibility Eduardo Habkost
2017-10-06 21:52 ` [Qemu-devel] [PATCH 7/7] target/i386: Enable kvm_pv_unhalt by default Eduardo Habkost
2017-10-09 14:40 ` Paolo Bonzini
2017-10-09 14:43 ` Alexander Graf
2017-10-09 13:39 ` [Qemu-devel] [PATCH 0/7] x86: Rework KVM-defaults compat code, enable " Paolo Bonzini
2017-10-09 15:15 ` Waiman Long
2017-10-09 15:47 ` Paolo Bonzini
2017-10-10 15:50 ` Eduardo Habkost
2017-10-10 18:07 ` Waiman Long [this message]
2017-10-10 19:41 ` Eduardo Habkost
2017-10-11 20:19 ` Waiman Long
2017-10-13 19:01 ` Eduardo Habkost
2017-10-13 20:58 ` Waiman Long
2017-10-13 23:56 ` Eduardo Habkost
2017-11-07 11:21 ` [Qemu-devel] [libvirt] " Paolo Bonzini
2017-11-08 20:07 ` Eduardo Habkost
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