From: Vincenzo Frascino <vincenzo.frascino@arm.com>
To: Thomas Gleixner <tglx@linutronix.de>, Huw Davies <huw@codeweavers.com>
Cc: linux kernel <linux-kernel@vger.kernel.org>,
Andy Lutomirski <luto@kernel.org>
Subject: Re: [PATCH 2/3] x86/vdso: Allow clock specific mult and shift values
Date: Mon, 15 Apr 2019 11:15:56 +0100 [thread overview]
Message-ID: <82a61daf-f6f9-8be0-2157-e9f9d7ba1cdf@arm.com> (raw)
In-Reply-To: <alpine.DEB.2.21.1904151148160.17231@nanos.tec.linutronix.de>
Hi Thomas,
On 15/04/2019 10:51, Thomas Gleixner wrote:
> On Mon, 15 Apr 2019, Huw Davies wrote:
>
>> On Sun, Apr 14, 2019 at 12:53:32PM +0200, Thomas Gleixner wrote:
>>> So it stays in the same cache line, but as we move the VDSO to generic
>>> code, the mask field needs to stay and this will make basetime[CLOCK_MONOTONIC]
>>> overlap into the next cache line.
>>
>> Thanks for the great review; this is a good point.
>>
>>> See https://lkml.kernel.org/r/alpine.DEB.2.21.1902231727060.1666@nanos.tec.linutronix.de
>>> for an alternate solution to this problem, which avoids this and just gives
>>> CLOCK_MONOTONIC_RAW a separate storage space alltogether.
>>
>> I can certainly do this for the x86 vdso. Would that be useful or
>> should I wait for Vincenzo's work on the generic vdso first?
>
> Depends. If Vincenzo comes along with his new version soon, then you might
> get this for free :)
>
> Vincenzo, what's the state of your work?
>
I am mostly done with the development, the only thing missing is the integration
of the generic update_vsyscall. After this is complete, I will need to do some
testing and extract the performance numbers.
Considering that I will be on Easter holiday from this Wednesday till the end of
April, I think v6 will be ready around second week of May.
> Thanks,
>
> tglx
>
--
Regards,
Vincenzo
next prev parent reply other threads:[~2019-04-15 10:16 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-04-11 10:12 [PATCH 0/3] x86/vdso: Add support for CLOCK_MONOTONIC_RAW in the vDSO Huw Davies
2019-04-11 10:12 ` [PATCH 1/3] x86/vdso: Remove unused 'mask' member Huw Davies
2019-04-14 10:36 ` Thomas Gleixner
2019-04-11 10:12 ` [PATCH 2/3] x86/vdso: Allow clock specific mult and shift values Huw Davies
2019-04-14 10:53 ` Thomas Gleixner
2019-04-15 9:30 ` Huw Davies
2019-04-15 9:51 ` Thomas Gleixner
2019-04-15 10:15 ` Vincenzo Frascino [this message]
2019-04-15 12:14 ` Huw Davies
2019-05-30 14:21 ` Vincenzo Frascino
2019-04-11 10:12 ` [PATCH 3/3] x86/vdso: Add support for CLOCK_MONOTONIC_RAW in the vDSO Huw Davies
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