Re: [PATCH 03/28] mm, page_alloc: Reduce branches in zone_statistics

[Vlastimil Babka]

On 04/15/2016 10:58 AM, Mel Gorman wrote:
> zone_statistics has more branches than it really needs to take an
> unlikely GFP flag into account. Reduce the number and annotate
> the unlikely flag.
>
> The performance difference on a page allocator microbenchmark is;
>
>                                             4.6.0-rc2                  4.6.0-rc2
>                                      nocompound-v1r10           statbranch-v1r10
> Min      alloc-odr0-1               417.00 (  0.00%)           419.00 ( -0.48%)
> Min      alloc-odr0-2               308.00 (  0.00%)           305.00 (  0.97%)
> Min      alloc-odr0-4               253.00 (  0.00%)           250.00 (  1.19%)
> Min      alloc-odr0-8               221.00 (  0.00%)           219.00 (  0.90%)
> Min      alloc-odr0-16              205.00 (  0.00%)           203.00 (  0.98%)
> Min      alloc-odr0-32              199.00 (  0.00%)           195.00 (  2.01%)
> Min      alloc-odr0-64              193.00 (  0.00%)           191.00 (  1.04%)
> Min      alloc-odr0-128             191.00 (  0.00%)           189.00 (  1.05%)
> Min      alloc-odr0-256             200.00 (  0.00%)           198.00 (  1.00%)
> Min      alloc-odr0-512             212.00 (  0.00%)           210.00 (  0.94%)
> Min      alloc-odr0-1024            219.00 (  0.00%)           216.00 (  1.37%)
> Min      alloc-odr0-2048            225.00 (  0.00%)           221.00 (  1.78%)
> Min      alloc-odr0-4096            231.00 (  0.00%)           227.00 (  1.73%)
> Min      alloc-odr0-8192            234.00 (  0.00%)           232.00 (  0.85%)
> Min      alloc-odr0-16384           234.00 (  0.00%)           232.00 (  0.85%)
>
> Signed-off-by: Mel Gorman <mgorman@xxxxxxxxxxxxxxxxxxx>

Acked-by: Vlastimil Babka <vbabka@xxxxxxx>