From: Vincenzo Frascino <vincenzo.frascino@arm.com>
To: Andre Przywara <andre.przywara@arm.com>
Cc: linux-arch@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org, linux-mips@vger.kernel.org,
linux-kselftest@vger.kernel.org, Shuah Khan <shuah@kernel.org>,
Arnd Bergmann <arnd@arndb.de>, Huw Davies <huw@codeweavers.com>,
Catalin Marinas <catalin.marinas@arm.com>,
Daniel Lezcano <daniel.lezcano@linaro.org>,
Will Deacon <will.deacon@arm.com>,
Russell King <linux@armlinux.org.uk>,
Ralf Baechle <ralf@linux-mips.org>,
Mark Salyzyn <salyzyn@android.com>,
Paul Burton <paul.burton@mips.com>,
Dmitry Safonov <0x7f454c46@gmail.com>,
Rasmus Villemoes <linux@rasmusvillemoes.dk>,
Thomas Gleixner <tglx@linutronix.de>,
Peter Collingbourne <pcc@google.com>
Subject: Re: [PATCH v6 00/19] Unify vDSOs across more architectures
Date: Fri, 21 Jun 2019 10:11:58 +0100
Message-ID: <40c3e4e9-96d3-f940-f5cb-ed97762ef9b0@arm.com> (raw)
In-Reply-To: <20190620172746.7f92cb14@donnerap.cambridge.arm.com>
On 20/06/2019 17:27, Andre Przywara wrote:
> On Thu, 30 May 2019 15:15:12 +0100
> Vincenzo Frascino <vincenzo.frascino@arm.com> wrote:
>
> Hi,
>
>> vDSO (virtual dynamic shared object) is a mechanism that the Linux
>> kernel provides as an alternative to system calls to reduce where
>> possible the costs in terms of cycles.
>> [ ... ]
>> The porting has been benchmarked and the performance results are
>> provided as part of this cover letter.
>
> I can't reveal the absolute numbers here, but vdsotest-bench gives me
> quite some performance gain on my board here ("time needed on v6" divided
> by "time needed on 5.2-rc1", so smaller percentages are better):
> clock-gettime-monotonic: 23 %
> clock-gettime-monotonic-raw: 30 %
> clock-gettime-tai: 5 %
> clock-getres-tai: 5 %
> clock-gettime-boottime: 5 %
> clock-getres-boottime: 5 %
> clock-gettime-realtime: 25 %
> gettimeofday: 26 %
> The other numbers stayed the same or differed by just 1 ns, which seems to
> be within the margin of error, as repeated runs on the same kernel suggest.
> The 5% numbers are of course those were we went from a syscall-only to the
> newly added arm64 VDSO implementation, but even the other calls improved
> by a factor of 3 or more.
>
> Sounds like a strong indicator that this is a good thing to have.
>
> Not sure if "running some benchmark a couple of times on a single machine"
> qualifies for this, but I guess it means:
>
> Tested-by: Andre Przywara <andre.przywara@arm.com>
>
Thanks Andre, it sounds great! I will add your tag as well to my patches.
> Cheers,
> Andre.
>
--
Regards,
Vincenzo
prev parent reply index
Thread overview: 69+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-05-30 14:15 Vincenzo Frascino
2019-05-30 14:15 ` [PATCH v6 01/19] kernel: Standardize vdso_datapage Vincenzo Frascino
2019-05-31 8:16 ` Arnd Bergmann
2019-06-04 12:05 ` Vincenzo Frascino
2019-06-10 17:47 ` Huw Davies
2019-06-10 9:27 ` Huw Davies
2019-06-10 10:17 ` Vincenzo Frascino
2019-06-10 10:31 ` Huw Davies
2019-06-10 11:07 ` Vincenzo Frascino
2019-06-10 11:37 ` Huw Davies
2019-05-30 14:15 ` [PATCH v6 02/19] kernel: Define gettimeofday vdso common code Vincenzo Frascino
2019-05-31 8:19 ` Arnd Bergmann
2019-06-04 12:08 ` Vincenzo Frascino
2019-06-10 9:31 ` Huw Davies
2019-06-10 10:18 ` Vincenzo Frascino
2019-05-30 14:15 ` [PATCH v6 03/19] kernel: Unify update_vsyscall implementation Vincenzo Frascino
2019-06-10 9:34 ` Huw Davies
2019-06-10 10:19 ` Vincenzo Frascino
2019-06-14 11:10 ` Thomas Gleixner
2019-06-14 12:15 ` Vincenzo Frascino
2019-06-14 12:19 ` Thomas Gleixner
2019-06-14 12:25 ` Vincenzo Frascino
2019-06-14 13:07 ` Thomas Gleixner
2019-05-30 14:15 ` [PATCH v6 04/19] arm64: Substitute gettimeofday with C implementation Vincenzo Frascino
2019-05-30 14:15 ` [PATCH v6 05/19] arm64: Build vDSO with -ffixed-x18 Vincenzo Frascino
2019-05-30 14:15 ` [PATCH v6 06/19] arm64: compat: Add missing syscall numbers Vincenzo Frascino
2019-05-30 14:15 ` [PATCH v6 07/19] arm64: compat: Expose signal related structures Vincenzo Frascino
2019-05-30 14:15 ` [PATCH v6 08/19] arm64: compat: Generate asm offsets for signals Vincenzo Frascino
2019-05-30 14:15 ` [PATCH v6 09/19] lib: vdso: Add compat support Vincenzo Frascino
2019-05-30 14:15 ` [PATCH v6 10/19] arm64: compat: Add vDSO Vincenzo Frascino
2019-05-30 14:15 ` [PATCH v6 11/19] arm64: Refactor vDSO code Vincenzo Frascino
2019-05-30 14:15 ` [PATCH v6 12/19] arm64: compat: vDSO setup for compat layer Vincenzo Frascino
2019-05-30 14:15 ` [PATCH v6 13/19] arm64: elf: vDSO code page discovery Vincenzo Frascino
2019-05-30 14:15 ` [PATCH v6 14/19] arm64: compat: Get sigreturn trampolines from vDSO Vincenzo Frascino
2019-05-30 14:15 ` [PATCH v6 15/19] arm64: Add vDSO compat support Vincenzo Frascino
2019-06-01 9:38 ` Catalin Marinas
2019-06-04 12:10 ` Vincenzo Frascino
2019-05-30 14:15 ` [PATCH v6 16/19] arm: Add support for generic vDSO Vincenzo Frascino
2019-05-31 8:32 ` Arnd Bergmann
2019-05-30 14:15 ` [PATCH v6 17/19] mips: " Vincenzo Frascino
2019-05-31 8:34 ` Arnd Bergmann
2019-06-03 14:54 ` Mark Salyzyn
2019-06-03 17:07 ` Arnd Bergmann
2019-05-30 14:15 ` [PATCH v6 18/19] x86: " Vincenzo Frascino
2019-05-30 15:41 ` Michael Kelley
2019-06-04 12:13 ` Vincenzo Frascino
2019-06-14 11:15 ` Thomas Gleixner
2019-06-14 21:17 ` Sasha Levin
2019-06-22 14:46 ` Thomas Gleixner
2019-06-23 19:09 ` Sasha Levin
2019-06-23 21:58 ` Stephen Rothwell
2019-06-24 0:24 ` Sasha Levin
2019-06-24 1:20 ` Stephen Rothwell
2019-06-23 22:12 ` Thomas Gleixner
2019-06-24 0:04 ` Michael Kelley
2019-06-24 0:25 ` Thomas Gleixner
2019-06-28 18:40 ` Michael Kelley
2019-05-30 14:15 ` [PATCH v6 19/19] kselftest: Extend vDSO selftest Vincenzo Frascino
2019-05-31 8:53 ` Arnd Bergmann
2019-05-31 8:46 ` [PATCH v6 00/19] Unify vDSOs across more architectures Arnd Bergmann
2019-06-04 12:04 ` Vincenzo Frascino
2019-06-04 12:12 ` Arnd Bergmann
2019-06-05 14:32 ` Vincenzo Frascino
2019-06-14 12:16 ` Thomas Gleixner
2019-06-14 12:19 ` Vincenzo Frascino
2019-06-20 6:17 ` Shijith Thotton
2019-06-20 8:55 ` Vincenzo Frascino
2019-06-20 16:27 ` Andre Przywara
2019-06-21 9:11 ` Vincenzo Frascino [this message]
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