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From: Bharata B Rao <bharata@amd.com>
To: "Huang, Ying" <ying.huang@intel.com>
Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org,
	mgorman@suse.de, peterz@infradead.org, mingo@redhat.com,
	bp@alien8.de, dave.hansen@linux.intel.com, x86@kernel.org,
	akpm@linux-foundation.org, luto@kernel.org, tglx@linutronix.de,
	yue.li@memverge.com, Ravikumar.Bangoria@amd.com
Subject: Re: [RFC PATCH 0/5] Memory access profiler(IBS) driven NUMA balancing
Date: Mon, 6 Mar 2023 21:00:47 +0530	[thread overview]
Message-ID: <55a344fa-4325-e82d-eeaa-1a77611ff513@amd.com> (raw)
In-Reply-To: <87356m8jo1.fsf@yhuang6-desk2.ccr.corp.intel.com>

On 03-Mar-23 11:23 AM, Huang, Ying wrote:
> 
> What is the memory accessing pattern of the workload?  Uniform random or
> something like Gauss distribution?

Multiple iterations of uniform access from beginning to end of the
memory region.

> 
> Anyway, it may take some time for the original method to scan enough
> memory space to trigger enough hint page fault.  We can check
> numa_pte_updates to check whether enough virtual space has been scanned.

I see that numa_hint_faults is way higher (sometimes close to 5 times)
than numa_pte_updates. This doesn't make sense. Very rarely I do see
saner numbers and when that happens the benchmark score is also much better.

Looks like an issue with the default kernel itself. I will debug this
further and get back.

Regards,
Bharata.


  reply	other threads:[~2023-03-06 15:31 UTC|newest]

Thread overview: 33+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-02-08  7:35 [RFC PATCH 0/5] Memory access profiler(IBS) driven NUMA balancing Bharata B Rao
2023-02-08  7:35 ` [RFC PATCH 1/5] x86/ibs: In-kernel IBS driver for page access profiling Bharata B Rao
2023-02-08  7:35 ` [RFC PATCH 2/5] x86/ibs: Drive NUMA balancing via IBS access data Bharata B Rao
2023-02-08  7:35 ` [RFC PATCH 3/5] x86/ibs: Enable per-process IBS from sched switch path Bharata B Rao
2023-02-08  7:35 ` [RFC PATCH 4/5] x86/ibs: Adjust access faults sampling period Bharata B Rao
2023-02-08  7:35 ` [RFC PATCH 5/5] x86/ibs: Delay the collection of HW-provided access info Bharata B Rao
2023-02-08 18:03 ` [RFC PATCH 0/5] Memory access profiler(IBS) driven NUMA balancing Peter Zijlstra
2023-02-08 18:12   ` Dave Hansen
2023-02-09  6:04     ` Bharata B Rao
2023-02-09 14:28       ` Dave Hansen
2023-02-10  4:28         ` Bharata B Rao
2023-02-10  4:40           ` Dave Hansen
2023-02-10 15:10             ` Bharata B Rao
2023-02-09  5:57   ` Bharata B Rao
2023-02-13  2:56     ` Huang, Ying
2023-02-13  3:23       ` Bharata B Rao
2023-02-13  3:34         ` Huang, Ying
2023-02-13  3:26 ` Huang, Ying
2023-02-13  5:52   ` Bharata B Rao
2023-02-13  6:30     ` Huang, Ying
2023-02-14  4:55       ` Bharata B Rao
2023-02-15  6:07         ` Huang, Ying
2023-02-24  3:28           ` Bharata B Rao
2023-02-16  8:41         ` Bharata B Rao
2023-02-17  6:03           ` Huang, Ying
2023-02-24  3:36             ` Bharata B Rao
2023-02-27  7:54               ` Huang, Ying
2023-03-01 11:21                 ` Bharata B Rao
2023-03-02  8:10                   ` Huang, Ying
2023-03-03  5:25                     ` Bharata B Rao
2023-03-03  5:53                       ` Huang, Ying
2023-03-06 15:30                         ` Bharata B Rao [this message]
2023-03-07  2:33                           ` Huang, Ying

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