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Groups > linux.kernel > #1537856
| From | Dave Hansen <dave.hansen@intel.com> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | Re: [PATCH kernel v5 0/5] Extend virtio-balloon for fast (de)inflating & fast live migration |
| Date | 2016-12-07 16:50 +0100 |
| Message-ID | <sLMDM-1V4-41@gated-at.bofh.it> (permalink) |
| References | <sJ8U9-3QS-5@gated-at.bofh.it> <sLjBM-8aU-41@gated-at.bofh.it> <sLKBY-Fd-23@gated-at.bofh.it> <sLMDM-1V4-37@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
On 12/07/2016 07:42 AM, David Hildenbrand wrote:
> Am 07.12.2016 um 14:35 schrieb Li, Liang Z:
>>> Am 30.11.2016 um 09:43 schrieb Liang Li:
>>>> This patch set contains two parts of changes to the virtio-balloon.
>>>>
>>>> One is the change for speeding up the inflating & deflating process,
>>>> the main idea of this optimization is to use bitmap to send the page
>>>> information to host instead of the PFNs, to reduce the overhead of
>>>> virtio data transmission, address translation and madvise(). This can
>>>> help to improve the performance by about 85%.
>>>
>>> Do you have some statistics/some rough feeling how many consecutive
>>> bits are
>>> usually set in the bitmaps? Is it really just purely random or is
>>> there some
>>> granularity that is usually consecutive?
>>>
>>
>> I did something similar. Filled the balloon with 15GB for a 16GB idle
>> guest, by
>> using bitmap, the madvise count was reduced to 605. when using the
>> PFNs, the madvise count
>> was 3932160. It means there are quite a lot consecutive bits in the
>> bitmap.
>> I didn't test for a guest with heavy memory workload.
>
> Would it then even make sense to go one step further and report {pfn,
> length} combinations?
>
> So simply send over an array of {pfn, length}?
Li's current patches do that. Well, maybe not pfn/length, but they do
take a pfn and page-order, which fits perfectly with the kernel's
concept of high-order pages.
> And it makes sense if you think about:
>
> a) hugetlb backing: The host may only be able to free huge pages (we
> might want to communicate that to the guest later, that's another
> story). Still we would have to send bitmaps full of 4k frames (512 bits
> for 2mb frames). Of course, we could add a way to communicate that we
> are using a different bitmap-granularity.
Yeah, please read the patches. If they're not clear, then the
descriptions need work, but this is done already.
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[PATCH kernel v5 0/5] Extend virtio-balloon for fast (de)inflating & fast live migration Liang Li <liang.z.li@intel.com> - 2016-11-30 10:00 +0100
[PATCH kernel v5 5/5] virtio-balloon: tell host vm's unused page info Liang Li <liang.z.li@intel.com> - 2016-11-30 10:00 +0100
Re: [PATCH kernel v5 5/5] virtio-balloon: tell host vm's unused page info Dave Hansen <dave.hansen@intel.com> - 2016-11-30 20:20 +0100
RE: [PATCH kernel v5 5/5] virtio-balloon: tell host vm's unused page info "Li, Liang Z" <liang.z.li@intel.com> - 2016-12-04 14:20 +0100
Re: [PATCH kernel v5 5/5] virtio-balloon: tell host vm's unused page info Dave Hansen <dave.hansen@intel.com> - 2016-12-05 18:30 +0100
RE: [PATCH kernel v5 5/5] virtio-balloon: tell host vm's unused page info "Li, Liang Z" <liang.z.li@intel.com> - 2016-12-06 05:50 +0100
[PATCH kernel v5 2/5] virtio-balloon: define new feature bit and head struct Liang Li <liang.z.li@intel.com> - 2016-11-30 10:00 +0100
[PATCH kernel v5 4/5] virtio-balloon: define flags and head for host request vq Liang Li <liang.z.li@intel.com> - 2016-11-30 10:00 +0100
[PATCH kernel v5 1/5] virtio-balloon: rework deflate to add page to a list Liang Li <liang.z.li@intel.com> - 2016-11-30 10:00 +0100
Re: [PATCH kernel v5 0/5] Extend virtio-balloon for fast (de)inflating & fast live migration David Hildenbrand <david@redhat.com> - 2016-12-06 09:50 +0100
RE: [PATCH kernel v5 0/5] Extend virtio-balloon for fast (de)inflating & fast live migration "Li, Liang Z" <liang.z.li@intel.com> - 2016-12-07 14:40 +0100
Re: [PATCH kernel v5 0/5] Extend virtio-balloon for fast (de)inflating & fast live migration Dave Hansen <dave.hansen@intel.com> - 2016-12-07 16:40 +0100
RE: [PATCH kernel v5 0/5] Extend virtio-balloon for fast (de)inflating & fast live migration "Li, Liang Z" <liang.z.li@intel.com> - 2016-12-09 04:10 +0100
Re: [PATCH kernel v5 0/5] Extend virtio-balloon for fast (de)inflating & fast live migration Dave Hansen <dave.hansen@intel.com> - 2016-12-07 16:50 +0100
Re: [PATCH kernel v5 0/5] Extend virtio-balloon for fast (de)inflating & fast live migration David Hildenbrand <david@redhat.com> - 2016-12-07 17:30 +0100
Re: [PATCH kernel v5 0/5] Extend virtio-balloon for fast (de)inflating & fast live migration Dave Hansen <dave.hansen@intel.com> - 2016-12-07 18:00 +0100
Re: [Qemu-devel] [PATCH kernel v5 0/5] Extend virtio-balloon for fast (de)inflating & fast live migration Andrea Arcangeli <aarcange@redhat.com> - 2016-12-07 19:40 +0100
Re: [Qemu-devel] [PATCH kernel v5 0/5] Extend virtio-balloon for fast (de)inflating & fast live migration Dave Hansen <dave.hansen@intel.com> - 2016-12-07 20:00 +0100
Re: [Qemu-devel] [PATCH kernel v5 0/5] Extend virtio-balloon for fast (de)inflating & fast live migration Andrea Arcangeli <aarcange@redhat.com> - 2016-12-07 20:00 +0100
Re: [Qemu-devel] [PATCH kernel v5 0/5] Extend virtio-balloon for fast (de)inflating & fast live migration Dave Hansen <dave.hansen@intel.com> - 2016-12-07 21:00 +0100
Re: [Qemu-devel] [PATCH kernel v5 0/5] Extend virtio-balloon for fast (de)inflating & fast live migration Andrea Arcangeli <aarcange@redhat.com> - 2016-12-07 21:30 +0100
RE: [Qemu-devel] [PATCH kernel v5 0/5] Extend virtio-balloon for fast (de)inflating & fast live migration "Li, Liang Z" <liang.z.li@intel.com> - 2016-12-09 05:50 +0100
Re: [Qemu-devel] [PATCH kernel v5 0/5] Extend virtio-balloon for fast (de)inflating & fast live migration Dave Hansen <dave.hansen@intel.com> - 2016-12-09 06:00 +0100
RE: [Qemu-devel] [PATCH kernel v5 0/5] Extend virtio-balloon for fast (de)inflating & fast live migration "Li, Liang Z" <liang.z.li@intel.com> - 2016-12-09 06:40 +0100
Re: [Qemu-devel] [PATCH kernel v5 0/5] Extend virtio-balloon for fast (de)inflating & fast live migration Andrea Arcangeli <aarcange@redhat.com> - 2016-12-09 17:50 +0100
Re: [PATCH kernel v5 0/5] Extend virtio-balloon for fast (de)inflating & fast live migration David Hildenbrand <david@redhat.com> - 2016-12-07 16:50 +0100
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