Re: [PATCH 0/6] Enable parallel page migration

Balbir Singh
2017-02-22T05:04:47Z

On Fri, Feb 17, 2017 at 04:54:47PM +0530, Anshuman Khandual wrote:
> This patch series is base on the work posted by Zi Yan back in
> November 2016 (https://lkml.org/lkml/2016/11/22/457) but includes some
> amount clean up and re-organization. This series depends on THP migration
> optimization patch series posted by Naoya Horiguchi on 8th November 2016
> (https://lwn.net/Articles/705879/). Though Zi Yan has recently reposted
> V3 of the THP migration patch series (https://lwn.net/Articles/713667/),
> this series is yet to be rebased.
>
> Primary motivation behind this patch series is to achieve higher
> bandwidth of memory migration when ever possible using multi threaded
> instead of a single threaded copy. Did all the experiments using a two
> socket X86 sytsem (Intel(R) Xeon(R) CPU E5-2650). All the experiments
> here have same allocation size 4K * 100000 (which did not split evenly
> for the 2MB huge pages). Here are the results.
>
> Vanilla:
>
> Moved 100000 normal pages in 247.000000 msecs 1.544412 GBs
> Moved 100000 normal pages in 238.000000 msecs 1.602814 GBs
> Moved 195 huge pages in 252.000000 msecs 1.513769 GBs
> Moved 195 huge pages in 257.000000 msecs 1.484318 GBs
>
> THP migration improvements:
>
> Moved 100000 normal pages in 302.000000 msecs 1.263145 GBs

Is there a decrease here for normal pages?

> Moved 100000 normal pages in 262.000000 msecs 1.455991 GBs
> Moved 195 huge pages in 120.000000 msecs 3.178914 GBs
> Moved 195 huge pages in 129.000000 msecs 2.957130 GBs
>
> THP migration improvements + Multi threaded page copy:
>
> Moved 100000 normal pages in 1589.000000 msecs 0.240069 GBs **

Ditto?

> Moved 100000 normal pages in 1932.000000 msecs 0.197448 GBs **
> Moved 195 huge pages in 54.000000 msecs 7.064254 GBs ***
> Moved 195 huge pages in 86.000000 msecs 4.435694 GBs ***
>

Could you also comment on the CPU utilization impact of these
patches.

Balbir Singh.