Re: [PATCH] virtio_balloon: high order allocation

[David Hildenbrand]

On 23.12.22 10:35, Soichiro Ueda wrote:
> At present, the VirtIO balloon device driver allocates pages
> one by one using alloc_page(), and frees them using put_page().
>
> This changes it so that the driver allocates high order pages
> by using alloc_pages(), and frees them using __free_pages() if possible.
> By doing so, the CPU performance of inflation and deflation
> should be improved.
>
> The effect of this change has been confirmed by benchmarks that measure
> the elapsed time of inflation and deflation.
>
> The results are here:
>
> 16 pages inflation:
>    before: 119,779 ns
>    after : 115,655 ns (-3.4%)
> 64 pages inflation:
>    before: 156,977 ns
>    after : 150,961 ns (-3.8%)
> 256 pages inflation:
>    before: 218,649 ns
>    after : 208,490 ns (-4.6%)
> 16 pages deflation:
>    before: 78,112 ns
>    after : 68,288 ns (-12.6%)
> 64 pages deflation:
>    before: 97,205 ns
>    after : 80,491 ns (-17.194%)
> 256 pages deflation:
>    before: 122,742 ns
>    after : 107,526 ns (-12.4%)

How does this affect page migration / balloon compaction etc?

--
Thanks,

David / dhildenb