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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