Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
Message-ID: <4d3c777e-20bd-b1f2-12ba-6af9d08cca45@intel.com>
Date:   Thu, 24 Feb 2022 16:49:43 -0800
MIME-Version: 1.0
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101
 Thunderbird/91.5.0
Content-Language: en-US
To:     Abhishek Goel <huntbag@linux.vnet.ibm.com>,
        Dave Hansen <dave.hansen@linux.intel.com>
Cc:     linux-mm@kvack.org, linux-kernel@vger.kernel.org,
        Zi Yan <ziy@nvidia.com>, David Hildenbrand <david@redhat.com>,
        Yang Shi <yang.shi@linux.alibaba.com>,
        Huang Ying <ying.huang@intel.com>,
        Andrew Morton <akpm@linux-foundation.org>
References: <20210721063926.3024591-1-ying.huang@intel.com>
 <20210721063926.3024591-2-ying.huang@intel.com>
 <eb438ddd-2919-73d4-bd9f-b7eecdd9577a@linux.vnet.ibm.com>
 <f5edb9dc-8b25-47c2-9905-09e88e41861b@intel.com>
 <4e8067e1-0574-c9d2-9d6c-d676d32071bd@linux.vnet.ibm.com>
From:   Dave Hansen <dave.hansen@intel.com>
Subject: Re: [PATCH -V11 2/9] mm/migrate: update node demotion order on
 hotplug events
In-Reply-To: <4e8067e1-0574-c9d2-9d6c-d676d32071bd@linux.vnet.ibm.com>
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
Precedence: bulk

On 2/24/22 15:37, Abhishek Goel wrote:
> 
> On 24/02/22 05:35, Dave Hansen wrote:
>> On 2/23/22 15:02, Abhishek Goel wrote:
>>> If needed, I will provide experiment results and traces that were used
>>> to conclude this.
>> It would be great if you can provide some more info.  Even just a CPU
>> time profile would be helpful.
> 
> Average total time taken for SMT=8 to SMT=1 in v5.14 : 20s
> 
> Average total time taken for SMT=8 to SMT=1 in v5.15 : 36s
> 
> (Observed in system with 150+ CPUs )

I was kinda thinking of:

	perf record / perf report

output.  Not wall clock time.  We need to know what the kernel is doing
during those extra 16 seconds.