From: Nathan_Lynch@mentor•com (Nathan Lynch)
To: linux-arm-kernel@lists•infradead.org
Subject: [PATCH v9 0/6] ARM: VDSO
Date: Fri, 5 Sep 2014 21:32:49 -0500 [thread overview]
Message-ID: <540A7251.8050708@mentor.com> (raw)
In-Reply-To: <1408744351-7814-1-git-send-email-nathan_lynch@mentor.com>
On 08/22/2014 04:52 PM, Nathan Lynch wrote:
> Provide fast userspace implementations of gettimeofday and
> clock_gettime on systems that implement the generic timers extension
> defined in ARMv7. This follows the example of arm64 in conception but
> significantly differs in some aspects of the implementation (C vs
> assembly, mainly).
>
> Clocks supported:
> - CLOCK_REALTIME
> - CLOCK_MONOTONIC
> - CLOCK_REALTIME_COARSE
> - CLOCK_MONOTONIC_COARSE
>
> This also provides clock_getres (as arm64 does).
>
> getcpu support is planned but not included at this time.
>
> For applications to transparently benefit from this change,
> ARM-specific support code needs to be added to glibc. I have such a
> patch, and have verified that glibc's self tests do not detect any
> regressions. I hope to have that code added to glibc for the 2.21
> release.
>
> The VDSO symbols are available for lookup via dlsym even with an
> unpatched glibc.
>
> Note that while the high-precision realtime and monotonic clock
> support depends on the generic timers extension, support for
> clock_getres and coarse clocks is independent of the timer
> implementation and is provided unconditionally. High-resolution clock
> support requires changes to the arch timer code, posted here:
>
> http://lists.infradead.org/pipermail/linux-arm-kernel/2014-August/281280.html
>
> The VDSO will function correctly without those changes, but
> gettimeofday and clock_gettime with CLOCK_REALTIME/CLOCK_MONOTONIC
> will not be accelerated.
Russell, what is your current thinking on taking the VDSO patches? I
believe all feedback has been addressed and I was hoping to get it into
3.18...
prev parent reply other threads:[~2014-09-06 2:32 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-08-22 21:52 [PATCH v9 0/6] ARM: VDSO Nathan Lynch
2014-08-22 21:52 ` [PATCH v9 1/6] ARM: use _install_special_mapping for sigpage Nathan Lynch
2014-08-22 21:52 ` [PATCH v9 2/6] ARM: place sigpage at a random offset above stack Nathan Lynch
2014-08-22 21:52 ` [PATCH v9 3/6] ARM: miscellaneous vdso infrastructure, preparation Nathan Lynch
2014-08-22 21:52 ` [PATCH v9 4/6] ARM: add vdso user-space code Nathan Lynch
2014-09-10 16:47 ` Will Deacon
2014-09-10 16:52 ` Andy Lutomirski
2014-09-10 17:10 ` Will Deacon
2014-09-10 17:25 ` Nathan Lynch
2014-09-12 6:50 ` Nathan Lynch
2014-08-22 21:52 ` [PATCH v9 5/6] ARM: vdso initialization, mapping, and synchronization Nathan Lynch
2014-08-22 21:52 ` [PATCH v9 6/6] ARM: add CONFIG_VDSO Kconfig and Makefile bits Nathan Lynch
2014-08-27 20:49 ` [PATCH v9 0/6] ARM: VDSO Christopher Covington
2014-08-27 21:42 ` Andy Lutomirski
2014-09-03 5:41 ` Nathan Lynch
2014-09-03 13:13 ` Christopher Covington
2014-09-03 16:59 ` Andy Lutomirski
2014-09-03 20:03 ` Nathan Lynch
2014-09-03 20:12 ` Andy Lutomirski
2014-09-06 2:32 ` Nathan Lynch [this message]
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