From: "Alex Zhu (Kernel)" <alexlzhu@fb.com>
To: Zi Yan <ziy@nvidia.com>
Cc: "linux-mm@kvack.org" <linux-mm@kvack.org>,
Matthew Wilcox <willy@infradead.org>,
"hannes@cmpxchg.org" <hannes@cmpxchg.org>,
"akpm@linux-foundation.org" <akpm@linux-foundation.org>,
"riel@surriel.com" <riel@surriel.com>,
Kernel Team <Kernel-team@fb.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [RFC 1/3] mm: add thp_utilization metrics to debugfs
Date: Mon, 29 Aug 2022 20:19:26 +0000 [thread overview]
Message-ID: <4847C6FE-429D-4619-9200-6CE7C84B5386@fb.com> (raw)
In-Reply-To: <CE4E09B8-4CDC-471D-9625-2CED7C95997B@nvidia.com>
> On Aug 26, 2022, at 5:11 PM, Zi Yan <ziy@nvidia.com> wrote:
>
> On 25 Aug 2022, at 17:30, alexlzhu@fb.com wrote:
>
> How large is the memory? Just wonder the scanning speed.
> Also, it might be better to explicitly add the time unit, second,
> in the output.
The size of memory was 65GB on the test machine I obtained these
numbers on. I’ll take note of adding the time unit. Thanks!
> Is it possible to use cache-bypassing read to avoid cache
> pollution? You are scanning for 256*2M at a time. Wouldn’t that
> wipe out all the useful data in the cache?
I have only found non-temporal writes in arch/x86/, not non-temporal reads (with MOVNTDQA). I suppose we should figure out why nobody ever bothered using non-temporal reads on x86 before trying to make this code use them.
A quick search of the internet suggests they non-temporal reads are not being used on x86 because people could not show a performance improvement by using them, but maybe somebody here has more insight?
next prev parent reply other threads:[~2022-08-29 20:19 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-08-25 21:30 [RFC 0/3] THP Shrinker alexlzhu
2022-08-25 21:30 ` [RFC 1/3] mm: add thp_utilization metrics to debugfs alexlzhu
2022-08-27 0:11 ` Zi Yan
2022-08-29 20:19 ` Alex Zhu (Kernel) [this message]
2022-08-25 21:30 ` [RFC 2/3] mm: changes to split_huge_page() to free zero filled tail pages alexlzhu
2022-08-26 10:18 ` David Hildenbrand
2022-08-26 18:34 ` Alex Zhu (Kernel)
2022-08-26 21:18 ` Rik van Riel
2022-08-29 10:02 ` David Hildenbrand
2022-08-29 13:17 ` Rik van Riel
2022-08-30 12:33 ` David Hildenbrand
2022-08-30 21:54 ` Alex Zhu (Kernel)
2022-08-25 21:30 ` [RFC 3/3] mm: THP low utilization shrinker alexlzhu
2022-08-27 0:25 ` Zi Yan
2022-08-29 20:49 ` Alex Zhu (Kernel)
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