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Date:   Fri, 23 Oct 2020 12:29:00 -0700 (PDT)
From:   David Rientjes <rientjes@google.com>
To:     kernel test robot <rong.a.chen@intel.com>,
        Axel Rasmussen <axelrasmussen@google.com>,
        Kevin Ko <kevko@google.com>
cc:     David Hildenbrand <david@redhat.com>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Andrew Morton <akpm@linux-foundation.org>,
        Vlastimil Babka <vbabka@suse.cz>,
        Oscar Salvador <osalvador@suse.de>,
        Wei Yang <richard.weiyang@linux.alibaba.com>,
        Pankaj Gupta <pankaj.gupta.linux@gmail.com>,
        Michal Hocko <mhocko@suse.com>,
        Alexander Duyck <alexander.h.duyck@linux.intel.com>,
        Mel Gorman <mgorman@techsingularity.net>,
        Dave Hansen <dave.hansen@intel.com>,
        Mike Rapoport <rppt@kernel.org>,
        "K. Y. Srinivasan" <kys@microsoft.com>,
        Haiyang Zhang <haiyangz@microsoft.com>,
        Stephen Hemminger <sthemmin@microsoft.com>,
        Wei Liu <wei.liu@kernel.org>,
        Matthew Wilcox <willy@infradead.org>,
        Michael Ellerman <mpe@ellerman.id.au>,
        Michal Hocko <mhocko@kernel.org>,
        Scott Cheloha <cheloha@linux.ibm.com>,
        LKML <linux-kernel@vger.kernel.org>, lkp@lists.01.org,
        lkp@intel.com, ying.huang@intel.com, feng.tang@intel.com,
        zhengjun.xing@intel.com
Subject: Re: [mm/page_alloc] 7fef431be9: vm-scalability.throughput 87.8%
 improvement
In-Reply-To: <20201021092417.GP11647@shao2-debian>
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References: <20201021092417.GP11647@shao2-debian>
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On Wed, 21 Oct 2020, kernel test robot wrote:

> Greeting,
> 
> FYI, we noticed a 87.8% improvement of vm-scalability.throughput due to commit:
> 
> 
> commit: 7fef431be9c9ac255838a9578331567b9dba4477 ("mm/page_alloc: place pages to tail in __free_pages_core()")
> https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git master
> 
> 
> in testcase: vm-scalability
> on test machine: 192 threads Intel(R) Xeon(R) Platinum 9242 CPU @ 2.30GHz with 192G memory
> with following parameters:
> 
> 	runtime: 300s
> 	size: 512G
> 	test: anon-wx-rand-mt
> 	cpufreq_governor: performance
> 	ucode: 0x5002f01
> 
> test-description: The motivation behind this suite is to exercise functions and regions of the mm/ of the Linux kernel which are of interest to us.
> test-url: https://git.kernel.org/cgit/linux/kernel/git/wfg/vm-scalability.git/
> 

I'm curious why we are not able to reproduce this improvement on Skylake 
and actually see a slight performance degradation, at least for 
300s_128G_truncate_throughput.

Axel Rasmussen <axelrasmussen@google.com> can provide more details on our 
results.