From: "Huang, Ying" <ying.huang@intel.com>
To: Bharata B Rao <bharata@amd.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: Tue, 07 Mar 2023 10:33:03 +0800 [thread overview]
Message-ID: <87ttyxb89s.fsf@yhuang6-desk2.ccr.corp.intel.com> (raw)
In-Reply-To: <55a344fa-4325-e82d-eeaa-1a77611ff513@amd.com> (Bharata B. Rao's message of "Mon, 6 Mar 2023 21:00:47 +0530")
Bharata B Rao <bharata@amd.com> writes:
> 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.
I guess this is sequential accesses instead of random accesses with
uniform distribution.
>>
>> 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.
Yes. It appears that something is wrong.
Best Regards,
Huang, Ying
prev parent reply other threads:[~2023-03-07 2:34 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-02-08 7:35 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
2023-03-07 2:33 ` Huang, Ying [this message]
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