From: Kemeng Shi <shikemeng@huawei.com>
To: Borislav Petkov <bp@alien8.de>
Cc: tglx@linutronix.de, mingo@redhat.com, x86@kernel.org,
hpa@zytor.com, linux-kernel@vger.kernel.org,
linux-nvdimm@lists.01.org
Subject: Re:Re: [PATCH] x86: Accelerate copy_page with non-temporal in X86
Date: Tue, 13 Apr 2021 20:54:55 +0800 [thread overview]
Message-ID: <bfa4fd38-0874-63b3-991a-1102af9f47a6@huawei.com> (raw)
In-Reply-To: <20210413110137.GD16519@zn.tnic>
on 2021/4/13 19:01, Borislav Petkov wrote:
> + linux-nvdimm
>
> Original mail at https://lkml.kernel.org/r/3f28adee-8214-fa8e-b368-eaf8b193469e@huawei.com
>
> On Tue, Apr 13, 2021 at 02:25:58PM +0800, Kemeng Shi wrote:
>> I'm using AEP with dax_kmem drvier, and AEP is export as a NUMA node in
>
> What is AEP?
>
AEP is a type of persistent memory produced by Intel. It's slower than
normal memory but is persistent.
>> my system. I will move cold pages from DRAM node to AEP node with
>> move_pages system call. With old "rep movsq', it costs 2030ms to move
>> 1 GB pages. With "movnti", it only cost about 890ms to move 1GB pages.
>
> So there's __copy_user_nocache() which does NT stores.
>
>> - ALTERNATIVE "jmp copy_page_regs", "", X86_FEATURE_REP_GOOD
>> + ALTERNATIVE_2 "jmp copy_page_regs", "", X86_FEATURE_REP_GOOD, \
>> + "jmp copy_page_nt", X86_FEATURE_XMM2
>
> This makes every machine which has sse2 do NT stores now. Which means
> *every* machine practically.
>
Yes. And NT stores should be better for copy_page especially copying a lot
of pages as only partial memory of copied page will be access recently.
> The folks on linux-nvdimm@ should be able to give you a better idea what
> to do.
>
> HTH.
>
Thanks for response and help.
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next prev parent reply other threads:[~2021-04-13 12:55 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <3f28adee-8214-fa8e-b368-eaf8b193469e@huawei.com>
2021-04-13 11:01 ` [PATCH] x86: Accelerate copy_page with non-temporal in X86 Borislav Petkov
2021-04-13 12:54 ` Kemeng Shi [this message]
2021-04-13 14:53 ` Borislav Petkov
2021-04-14 5:25 ` Kemeng Shi
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