From: Nathan_Lynch@mentor•com (Nathan Lynch)
To: linux-arm-kernel@lists•infradead.org
Subject: [PATCH v7 7/9] ARM: add vdso user-space code
Date: Sat, 28 Jun 2014 16:35:12 -0500 [thread overview]
Message-ID: <53AF3510.7030707@mentor.com> (raw)
In-Reply-To: <20140628201120.GK32514@n2100.arm.linux.org.uk>
On 06/28/2014 03:11 PM, Russell King - ARM Linux wrote:
> On Sat, Jun 28, 2014 at 02:45:41PM -0500, Nathan Lynch wrote:
>> On 06/28/2014 01:12 PM, Russell King - ARM Linux wrote:
>>> I know that I'm probably many years away from it, even if Ubuntu
>>> adopt it for something recent - I'm rather stuck with 12.04 due to
>>> the move towards requiring 3D GPU acceleration in later versions.
>>> It seems that the choices on ARM now are to either have a crippled
>>> distro through lack of open GPU support, or stick with an old distro
>>> that doesn't require GPUs.
>>
>> Based on other messages from you on the ML I'm assuming you have an
>> i.MX6 system in mind? (Forgive me if I'm wrong.) On any Cortex-A9 or
>> -A8 the VDSO isn't going to be any great benefit anyway. Those CPUs
>> don't implement the generic timers extension, so only clock_gettime()
>> with low-resolution clock ids will see a speedup. And few programs use
>> those, to my knowledge.
>>
>> A15, A7, and I'm pretty sure A12 and A17 all implement the timer
>> extension and will see full benefit. Some Qualcomm CPUs too, I think.
>
> Here's the results from vdsotest... yes on iMX6 as that's the most
> advanced bootable system I have:
>
> clock-gettime-monotonic system calls per second: 1601780
> clock-gettime-monotonic vdso calls per second: 1600862 (1.00x speedup)
> clock-getres-monotonic system calls per second: 3001396
> clock-getres-monotonic vdso calls per second: 52163259 (17.38x speedup)
> clock-gettime-monotonic-coarse system calls per second: 2824631
> clock-gettime-monotonic-coarse vdso calls per second: 13760820 (4.87x speedup)
> clock-getres-monotonic-coarse system calls per second: 3166932
> clock-getres-monotonic-coarse vdso calls per second: 52111805 (16.45x speedup)
> clock-gettime-realtime system calls per second: 1596863
> clock-gettime-realtime vdso calls per second: 1590424 (1.00x speedup)
> clock-getres-realtime system calls per second: 2993748
> clock-getres-realtime vdso calls per second: 52123753 (17.41x speedup)
> clock-gettime-realtime-coarse system calls per second: 3007894
> clock-gettime-realtime-coarse vdso calls per second: 17081617 (5.68x speedup)
> clock-getres-realtime-coarse system calls per second: 3072073
> clock-getres-realtime-coarse vdso calls per second: 49401452 (16.08x speedup)
> Note: vDSO version of getcpu not found
> getcpu system calls per second: 4902323
> getcpu vdso calls per second: 4972290 (1.01x speedup)
> Note: vDSO version of getcpu not found
> Note: vDSO version of getcpu not found
> gettimeofday system calls per second: 1637099
> gettimeofday vdso calls per second: 1637573 (1.00x speedup)
That's consistent with my results on iMX6. The reported 1.00x "speedup"
for clock-gettime-monotonic etc indicates the VDSO is falling back to
syscall.
Thanks for testing.
next prev parent reply other threads:[~2014-06-28 21:35 UTC|newest]
Thread overview: 76+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-06-23 3:11 [PATCH v7 0/9] ARM: VDSO Nathan Lynch
2014-06-23 3:11 ` [PATCH v7 1/9] clocksource: arm_arch_timer: change clocksource name if CP15 unavailable Nathan Lynch
2014-06-23 3:11 ` [PATCH v7 2/9] clocksource: arm_arch_timer: enable counter access for 32-bit ARM Nathan Lynch
2014-06-23 3:11 ` [PATCH v7 3/9] ARM: arch_timer: remove unused functions Nathan Lynch
2014-06-23 3:11 ` [PATCH v7 4/9] arm64: " Nathan Lynch
2014-06-23 3:11 ` [PATCH v7 5/9] ARM: place sigpage at a random offset above stack Nathan Lynch
2014-06-23 3:11 ` [PATCH v7 6/9] ARM: miscellaneous vdso infrastructure, preparation Nathan Lynch
2014-06-30 10:11 ` Arnd Bergmann
2014-06-30 12:27 ` Nathan Lynch
2014-06-30 13:06 ` Arnd Bergmann
2014-06-23 3:11 ` [PATCH v7 7/9] ARM: add vdso user-space code Nathan Lynch
2014-06-28 9:53 ` Russell King - ARM Linux
2014-06-28 10:03 ` Russell King - ARM Linux
2014-06-30 15:56 ` Andy Lutomirski
2014-06-28 15:19 ` Nathan Lynch
2014-06-28 15:26 ` Russell King - ARM Linux
2014-06-28 16:13 ` Nathan Lynch
2014-06-28 18:12 ` Russell King - ARM Linux
2014-06-28 19:45 ` Nathan Lynch
2014-06-28 20:11 ` Russell King - ARM Linux
2014-06-28 21:35 ` Nathan Lynch [this message]
2014-06-29 8:34 ` Russell King - ARM Linux
2014-06-29 15:48 ` Nathan Lynch
2014-06-29 16:07 ` Russell King - ARM Linux
2014-06-29 23:04 ` Nathan Lynch
2014-06-30 21:33 ` Andy Lutomirski
2014-06-30 15:59 ` Andy Lutomirski
2014-06-30 16:50 ` Nathan Lynch
2014-06-30 21:29 ` Andy Lutomirski
2014-07-01 9:00 ` Will Deacon
2014-07-01 13:34 ` Nathan Lynch
2014-07-01 14:11 ` Andy Lutomirski
2014-07-01 13:28 ` Nathan Lynch
2014-07-01 14:56 ` Andy Lutomirski
2014-06-23 3:11 ` [PATCH v7 8/9] ARM: vdso initialization, mapping, and synchronization Nathan Lynch
2014-06-30 21:37 ` Andy Lutomirski
2014-07-01 9:03 ` Will Deacon
2014-07-01 14:11 ` Nathan Lynch
2014-07-01 14:15 ` Will Deacon
2014-07-01 14:17 ` Andy Lutomirski
2014-07-01 17:27 ` Christopher Covington
2014-07-02 14:40 ` Will Deacon
2014-07-02 15:54 ` Andy Lutomirski
2014-07-02 16:18 ` Nathan Lynch
2014-07-02 16:27 ` Will Deacon
2014-07-02 16:47 ` Andy Lutomirski
2014-07-02 17:24 ` Will Deacon
2014-07-02 18:34 ` Andy Lutomirski
2014-07-02 18:54 ` Will Deacon
2014-07-22 0:14 ` Andy Lutomirski
2014-07-22 8:13 ` Will Deacon
2014-07-01 14:01 ` Nathan Lynch
2014-07-01 14:09 ` Andy Lutomirski
2014-07-01 14:14 ` Russell King - ARM Linux
2014-06-23 3:11 ` [PATCH v7 9/9] ARM: add CONFIG_VDSO Kconfig and Makefile bits Nathan Lynch
2014-06-27 8:51 ` [PATCH v7 0/9] ARM: VDSO Jan Glauber
2014-06-27 8:57 ` Russell King - ARM Linux
2014-06-27 9:41 ` Ard Biesheuvel
2014-06-27 9:46 ` Russell King - ARM Linux
2014-06-27 17:01 ` Nathan Lynch
2014-06-28 9:42 ` Russell King - ARM Linux
2014-06-28 9:55 ` Russell King - ARM Linux
2014-06-28 14:49 ` Russell King - ARM Linux
2014-06-30 7:27 ` Arnd Bergmann
2014-06-30 7:43 ` Arnd Bergmann
2014-06-30 18:27 ` Nathan Lynch
2014-06-27 16:00 ` Nathan Lynch
2014-06-30 16:03 ` Andy Lutomirski
2014-06-30 8:12 ` Ard Biesheuvel
2014-07-01 16:34 ` Nathan Lynch
2014-07-01 20:08 ` Ard Biesheuvel
2014-07-01 22:44 ` Russell King - ARM Linux
2014-06-30 14:40 ` Will Deacon
2014-06-30 15:42 ` Nathan Lynch
2014-06-30 21:56 ` Andy Lutomirski
2014-07-01 9:04 ` Will Deacon
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