From: Vincenzo Frascino <vincenzo.frascino@arm.com>
To: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-arch@vger.kernel.org, Shuah Khan <shuah@kernel.org>,
Arnd Bergmann <arnd@arndb.de>,
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>,
Peter Collingbourne <pcc@google.com>,
linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH v5 02/23] kernel: Define gettimeofday vdso common code
Date: Wed, 27 Feb 2019 16:06:49 +0000 [thread overview]
Message-ID: <65173128-04b3-fd03-247b-d090703244ac@arm.com> (raw)
In-Reply-To: <alpine.DEB.2.21.1902271640260.26197@nanos.tec.linutronix.de>
On 27/02/2019 15:49, Thomas Gleixner wrote:
> Vincenzo,
>
> On Wed, 27 Feb 2019, Vincenzo Frascino wrote:
>>
>> The clocksource array has two elements (CLOCKSOURCE_RAW, CLOCKSOURCE_MONO) and
>> the situation with my scheme should be the following:
>
> Oops. I misread the patch, but still...
>
>> u32 seq: + 0
>> s32 clock_mode; + 4
>> u64 cycle_last; + 8
>> struct vdso_cs cs[2]; + 16
>> struct vdso_ts basetime[VDSO_BASES]; + 48
>>
>> which I agree makes still things a bit worse.
>
>>> It's easy enough to benchmark these implementations and without trying I'm
>>> pretty sure that you can see the performance drop nicely. Please do so next
>>> time and provide the numbers in the changelogs.
>>>
>>
>> I did run some benchmarks this morning to quantify the performance impact and
>> seems that using vdsotest[1] the difference in between a stock linux kernel
>> 5.0.0-rc7 and one that has unified vDSO, running on my x86 machine (Xeon Gold
>> 5120T), is below 1%. Please find the results below, I will add them as well to
>> the next changelog.
>
> I have some doubts about 1%.
> NEW STOCK
> clock-gettime-monotonic: vdso: 31 28 ~ 10% slower
> clock-gettime-realtime: vdso: 32 29 ~ 10% slower
>
Sorry, there was an error in my script that I used to extract percentages. I
agree! Luckily I shared the numbers. Thanks Thomas.
> Thanks,
>
> tglx
>
--
Regards,
Vincenzo
WARNING: multiple messages have this Message-ID (diff)
From: Vincenzo Frascino <vincenzo.frascino@arm.com>
To: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-arch@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will.deacon@arm.com>, Arnd Bergmann <arnd@arndb.de>,
Russell King <linux@armlinux.org.uk>,
Ralf Baechle <ralf@linux-mips.org>,
Paul Burton <paul.burton@mips.com>,
Daniel Lezcano <daniel.lezcano@linaro.org>,
Mark Salyzyn <salyzyn@android.com>,
Peter Collingbourne <pcc@google.com>,
Shuah Khan <shuah@kernel.org>,
Dmitry Safonov <0x7f454c46@gmail.com>,
Rasmus Villemoes <linux@rasmusvillemoes.dk>
Subject: Re: [PATCH v5 02/23] kernel: Define gettimeofday vdso common code
Date: Wed, 27 Feb 2019 16:06:49 +0000 [thread overview]
Message-ID: <65173128-04b3-fd03-247b-d090703244ac@arm.com> (raw)
Message-ID: <20190227160649.RZkbv2YCnshXgK3BsAWCohwafJONA0fbySIoVdw5hoc@z> (raw)
In-Reply-To: <alpine.DEB.2.21.1902271640260.26197@nanos.tec.linutronix.de>
On 27/02/2019 15:49, Thomas Gleixner wrote:
> Vincenzo,
>
> On Wed, 27 Feb 2019, Vincenzo Frascino wrote:
>>
>> The clocksource array has two elements (CLOCKSOURCE_RAW, CLOCKSOURCE_MONO) and
>> the situation with my scheme should be the following:
>
> Oops. I misread the patch, but still...
>
>> u32 seq: + 0
>> s32 clock_mode; + 4
>> u64 cycle_last; + 8
>> struct vdso_cs cs[2]; + 16
>> struct vdso_ts basetime[VDSO_BASES]; + 48
>>
>> which I agree makes still things a bit worse.
>
>>> It's easy enough to benchmark these implementations and without trying I'm
>>> pretty sure that you can see the performance drop nicely. Please do so next
>>> time and provide the numbers in the changelogs.
>>>
>>
>> I did run some benchmarks this morning to quantify the performance impact and
>> seems that using vdsotest[1] the difference in between a stock linux kernel
>> 5.0.0-rc7 and one that has unified vDSO, running on my x86 machine (Xeon Gold
>> 5120T), is below 1%. Please find the results below, I will add them as well to
>> the next changelog.
>
> I have some doubts about 1%.
> NEW STOCK
> clock-gettime-monotonic: vdso: 31 28 ~ 10% slower
> clock-gettime-realtime: vdso: 32 29 ~ 10% slower
>
Sorry, there was an error in my script that I used to extract percentages. I
agree! Luckily I shared the numbers. Thanks Thomas.
> Thanks,
>
> tglx
>
--
Regards,
Vincenzo
next prev parent reply other threads:[~2019-02-27 16:06 UTC|newest]
Thread overview: 120+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-02-22 12:24 [PATCH v5 00/23] Unify vDSOs across more architectures Vincenzo Frascino
2019-02-22 12:24 ` Vincenzo Frascino
2019-02-22 12:24 ` [PATCH v5 01/23] kernel: Standardize vdso_datapage Vincenzo Frascino
2019-02-22 12:24 ` Vincenzo Frascino
2019-02-22 12:58 ` Mark Rutland
2019-02-22 12:58 ` Mark Rutland
2019-02-23 16:51 ` Thomas Gleixner
2019-02-23 16:51 ` Thomas Gleixner
2019-02-27 14:23 ` Vincenzo Frascino
2019-02-27 14:23 ` Vincenzo Frascino
2019-02-22 12:24 ` [PATCH v5 02/23] kernel: Define gettimeofday vdso common code Vincenzo Frascino
2019-02-22 12:24 ` Vincenzo Frascino
2019-02-22 13:34 ` Mark Rutland
2019-02-22 13:34 ` Mark Rutland
2019-02-22 13:49 ` Arnd Bergmann
2019-02-22 13:49 ` Arnd Bergmann
2019-02-22 14:36 ` Arnd Bergmann
2019-02-22 14:36 ` Arnd Bergmann
2019-02-27 14:52 ` Vincenzo Frascino
2019-02-27 14:52 ` Vincenzo Frascino
2019-02-28 9:29 ` Arnd Bergmann
2019-02-28 9:29 ` Arnd Bergmann
2019-02-28 11:58 ` [PATCH 1/2] vdso: use fixed-size time types Arnd Bergmann
2019-02-28 11:58 ` Arnd Bergmann
2019-02-28 11:58 ` [PATCH 2/2] vdso: add clock_gettime64 Arnd Bergmann
2019-02-28 11:58 ` Arnd Bergmann
2019-02-28 13:42 ` [PATCH 1/2] vdso: use fixed-size time types Thomas Gleixner
2019-02-28 13:42 ` Thomas Gleixner
2019-02-28 13:45 ` Vincenzo Frascino
2019-02-28 13:45 ` Vincenzo Frascino
2019-02-23 10:34 ` [PATCH v5 02/23] kernel: Define gettimeofday vdso common code Thomas Gleixner
2019-02-23 10:34 ` Thomas Gleixner
2019-02-25 14:09 ` Vincenzo Frascino
2019-02-25 14:09 ` Vincenzo Frascino
2019-02-23 17:31 ` Thomas Gleixner
2019-02-23 17:31 ` Thomas Gleixner
2019-02-27 13:47 ` Vincenzo Frascino
2019-02-27 13:47 ` Vincenzo Frascino
2019-02-27 15:49 ` Thomas Gleixner
2019-02-27 15:49 ` Thomas Gleixner
2019-02-27 16:06 ` Vincenzo Frascino [this message]
2019-02-27 16:06 ` Vincenzo Frascino
2019-02-22 12:24 ` [PATCH v5 03/23] arm64: Build vDSO with -ffixed-x18 Vincenzo Frascino
2019-02-22 12:24 ` Vincenzo Frascino
2019-02-22 12:24 ` [PATCH v5 04/23] arm64: Substitute gettimeofday with C implementation Vincenzo Frascino
2019-02-22 12:24 ` Vincenzo Frascino
2019-02-22 13:42 ` Mark Rutland
2019-02-22 13:42 ` Mark Rutland
2019-02-22 12:24 ` [PATCH v5 05/23] arm64: compat: Alloc separate pages for vectors and sigpage Vincenzo Frascino
2019-02-22 12:24 ` Vincenzo Frascino
2019-02-22 12:24 ` [PATCH v5 06/23] arm64: compat: Split kuser32 Vincenzo Frascino
2019-02-22 12:24 ` Vincenzo Frascino
2019-02-22 12:24 ` [PATCH v5 07/23] arm64: compat: Refactor aarch32_alloc_vdso_pages() Vincenzo Frascino
2019-02-22 12:24 ` Vincenzo Frascino
2019-02-22 12:24 ` [PATCH v5 08/23] arm64: compat: Add KUSER_HELPERS config option Vincenzo Frascino
2019-02-22 12:24 ` Vincenzo Frascino
2019-02-22 14:04 ` Mark Rutland
2019-02-22 14:04 ` Mark Rutland
2019-02-22 14:09 ` Russell King - ARM Linux admin
2019-02-22 14:09 ` Russell King - ARM Linux admin
2019-02-26 12:10 ` Vincenzo Frascino
2019-02-26 12:10 ` Vincenzo Frascino
2019-02-22 12:24 ` [PATCH v5 09/23] arm64: compat: Add missing syscall numbers Vincenzo Frascino
2019-02-22 12:24 ` Vincenzo Frascino
2019-02-22 12:24 ` [PATCH v5 10/23] arm64: compat: Expose signal related structures Vincenzo Frascino
2019-02-22 12:24 ` Vincenzo Frascino
2019-02-22 12:24 ` [PATCH v5 11/23] arm64: compat: Generate asm offsets for signals Vincenzo Frascino
2019-02-22 12:24 ` Vincenzo Frascino
2019-02-22 14:22 ` Mark Rutland
2019-02-22 14:22 ` Mark Rutland
2019-02-22 12:24 ` [PATCH v5 12/23] lib: vdso: Add compat support Vincenzo Frascino
2019-02-22 12:24 ` Vincenzo Frascino
2019-02-22 12:24 ` [PATCH v5 13/23] arm64: compat: Add vDSO Vincenzo Frascino
2019-02-22 12:24 ` Vincenzo Frascino
2019-02-22 14:32 ` Mark Rutland
2019-02-22 14:32 ` Mark Rutland
2019-02-22 12:24 ` [PATCH v5 14/23] arm64: Refactor vDSO code Vincenzo Frascino
2019-02-22 12:24 ` Vincenzo Frascino
2019-02-22 14:37 ` Mark Rutland
2019-02-22 14:37 ` Mark Rutland
2019-02-22 12:24 ` [PATCH v5 15/23] arm64: compat: vDSO setup for compat layer Vincenzo Frascino
2019-02-22 12:24 ` Vincenzo Frascino
2019-02-22 12:24 ` [PATCH v5 16/23] arm64: elf: vDSO code page discovery Vincenzo Frascino
2019-02-22 12:24 ` Vincenzo Frascino
2019-02-22 12:24 ` [PATCH v5 17/23] arm64: compat: Get sigreturn trampolines from vDSO Vincenzo Frascino
2019-02-22 12:24 ` Vincenzo Frascino
2019-02-22 12:24 ` [PATCH v5 18/23] arm64: Add vDSO compat support Vincenzo Frascino
2019-02-22 12:24 ` Vincenzo Frascino
2019-02-22 12:24 ` [PATCH v5 19/23] arm64: Enable compat vDSO support Vincenzo Frascino
2019-02-22 12:24 ` Vincenzo Frascino
2019-02-22 14:39 ` Mark Rutland
2019-02-22 14:39 ` Mark Rutland
2019-02-22 14:41 ` Mark Rutland
2019-02-22 14:41 ` Mark Rutland
2019-02-22 12:24 ` [PATCH v5 20/23] arm: Add support for generic vDSO Vincenzo Frascino
2019-02-22 12:24 ` Vincenzo Frascino
2019-02-22 12:24 ` [PATCH v5 21/23] mips: " Vincenzo Frascino
2019-02-22 12:24 ` Vincenzo Frascino
2019-02-22 12:24 ` [PATCH v5 22/23] x86: " Vincenzo Frascino
2019-02-22 12:24 ` Vincenzo Frascino
2019-02-23 10:45 ` Thomas Gleixner
2019-02-23 10:45 ` Thomas Gleixner
2019-02-27 16:18 ` Vincenzo Frascino
2019-02-27 16:18 ` Vincenzo Frascino
2019-02-22 12:24 ` [PATCH v5 23/23] kselftest: Extend vDSO selftest Vincenzo Frascino
2019-02-22 12:24 ` Vincenzo Frascino
2019-02-23 17:39 ` [PATCH v5 00/23] Unify vDSOs across more architectures Thomas Gleixner
2019-02-23 17:39 ` Thomas Gleixner
2019-02-28 11:40 ` Arnd Bergmann
2019-02-28 11:40 ` Arnd Bergmann
2019-02-28 12:09 ` Vincenzo Frascino
2019-02-28 12:09 ` Vincenzo Frascino
2019-02-28 12:38 ` Arnd Bergmann
2019-02-28 12:38 ` Arnd Bergmann
2019-02-28 12:42 ` Vincenzo Frascino
2019-02-28 12:42 ` Vincenzo Frascino
2019-02-28 13:54 ` Arnd Bergmann
2019-02-28 13:54 ` Arnd Bergmann
2019-02-28 15:51 ` Vincenzo Frascino
2019-02-28 15:51 ` Vincenzo Frascino
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=65173128-04b3-fd03-247b-d090703244ac@arm.com \
--to=vincenzo.frascino@arm.com \
--cc=0x7f454c46@gmail.com \
--cc=arnd@arndb.de \
--cc=catalin.marinas@arm.com \
--cc=daniel.lezcano@linaro.org \
--cc=linux-arch@vger.kernel.org \
--cc=linux-arm-kernel@lists.infradead.org \
--cc=linux@armlinux.org.uk \
--cc=linux@rasmusvillemoes.dk \
--cc=paul.burton@mips.com \
--cc=pcc@google.com \
--cc=ralf@linux-mips.org \
--cc=salyzyn@android.com \
--cc=shuah@kernel.org \
--cc=tglx@linutronix.de \
--cc=will.deacon@arm.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox