Re: [Xen-devel] Converting heap page_infos to contiguous virtual

[Boris Ostrovsky <boris.ostrovsky@xxxxxxxxxx>]

On 07/14/2016 09:29 AM, Andrew Cooper wrote:
>
> However, I would recommend getting something functioning first, before
> trying to optimise it.

There are two fairly independent parts to improving scrubbing: one is
making it asynchronous and second is improving clear_page() performance.
Whole-RAM mapping is needed for the latter.

>
> There is probably a lot to be gained simply by improving clear_page().

The biggest improvement comes from switching to AVX(2) when available.
It's been a while since I ran those tests so I will have to re-measure
it but my recollection is that 4K was too small to see significant changes.

A potential improvement might come from dropping (or, rather, deferring)
sfence in clear_page_sse2. I don't know how much this would buy us though.

-boris



_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxx
https://lists.xen.org/xen-devel