linux-kernel - Re: [PATCH v12 00/18] Enable FSGSBASE instructions

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Date:   Mon, 18 May 2020 08:33:59 -0400
From:   Sasha Levin <sashal@...nel.org>
To:     Christoph Hellwig <hch@...radead.org>
Cc:     linux-kernel@...r.kernel.org, tglx@...utronix.de, bp@...en8.de,
        luto@...nel.org, hpa@...or.com, dave.hansen@...el.com,
        tony.luck@...el.com, ak@...ux.intel.com, ravi.v.shankar@...el.com,
        chang.seok.bae@...el.com
Subject: Re: [PATCH v12 00/18] Enable FSGSBASE instructions

On Sun, May 17, 2020 at 11:18:36PM -0700, Christoph Hellwig wrote:
>On Mon, May 11, 2020 at 12:52:53AM -0400, Sasha Levin wrote:
>> Benefits:
>> Currently a user process that wishes to read or write the FS/GS base must
>> make a system call. But recent X86 processors have added new instructions
>> for use in 64-bit mode that allow direct access to the FS and GS segment
>> base addresses.  The operating system controls whether applications can
>> use these instructions with a %cr4 control bit.
>>
>> In addition to benefits to applications, performance improvements to the
>> OS context switch code are possible by making use of these instructions. A
>> third party reported out promising performance numbers out of their
>> initial benchmarking of the previous version of this patch series [9].
>
>The [9] reference can't be resolved anywhere in this mail.

Sorry, I'll fix it up. The reference was supposed to be pointing to:

	https://www.phoronix.com/scan.php?page=article&item=linux-wip-fsgsbase&num=1

-- 
Thanks,
Sasha