Linux-MIPS Archive on lore.kernel.org
 help / color / Atom feed
From: Christophe Leroy <christophe.leroy@c-s.fr>
To: Segher Boessenkool <segher@kernel.crashing.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>,
	Paul Mackerras <paulus@samba.org>,
	Michael Ellerman <mpe@ellerman.id.au>,
	nathanl@linux.ibm.com, arnd@arndb.de, tglx@linutronix.de,
	vincenzo.frascino@arm.com, luto@kernel.org, x86@kernel.org,
	linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org, linux-mips@vger.kernel.org
Subject: Re: [RFC PATCH v4 00/11] powerpc: switch VDSO to C implementation.
Date: Mon, 20 Jan 2020 14:56:00 +0000
Message-ID: <3027b6d2-47a9-a871-7c52-050a5f9c6ab7@c-s.fr> (raw)
In-Reply-To: <20200117085851.GS3191@gate.crashing.org>

Hi

On 01/17/2020 08:58 AM, Segher Boessenkool wrote:
> Hi!
> 
> On Thu, Jan 16, 2020 at 05:58:24PM +0000, Christophe Leroy wrote:
>> On a powerpc8xx, with current powerpc/32 ASM VDSO:
>>
>> gettimeofday:    vdso: 907 nsec/call
>> clock-getres-realtime:    vdso: 484 nsec/call
>> clock-gettime-realtime:    vdso: 899 nsec/call
>>
>> The first patch adds VDSO generic C support without any changes to common code.
>> Performance is as follows:
>>
>> gettimeofday:    vdso: 1211 nsec/call
>> clock-getres-realtime:    vdso: 722 nsec/call
>> clock-gettime-realtime:    vdso: 1216 nsec/call
>>
>> Then a few changes in the common code have allowed performance improvement. At
>> the end of the series we have:
>>
>> gettimeofday:    vdso: 974 nsec/call
>> clock-getres-realtime:    vdso: 545 nsec/call
>> clock-gettime-realtime:    vdso: 941 nsec/call
>>
>> The final result is rather close to pure ASM VDSO:
>> * 7% more on gettimeofday (9 cycles)
>> * 5% more on clock-gettime-realtime (6 cycles)
>> * 12% more on clock-getres-realtime (8 cycles)
> 
> Nice!  Much better.
> 
> It should be tested on more representative hardware, too, but this looks
> promising alright :-)
> 

mpc832x (e300c2 core) at 333 MHz:

Before:

gettimeofday:    vdso: 235 nsec/call
clock-getres-realtime-coarse:    vdso: 1668 nsec/call
clock-gettime-realtime-coarse:    vdso: 1338 nsec/call
clock-getres-realtime:    vdso: 135 nsec/call
clock-gettime-realtime:    vdso: 244 nsec/call
clock-getres-boottime:    vdso: 1232 nsec/call
clock-gettime-boottime:    vdso: 1935 nsec/call
clock-getres-tai:    vdso: 1257 nsec/call
clock-gettime-tai:    vdso: 1898 nsec/call
clock-getres-monotonic-raw:    vdso: 1229 nsec/call
clock-gettime-monotonic-raw:    vdso: 1541 nsec/call
clock-getres-monotonic-coarse:    vdso: 1699 nsec/call
clock-gettime-monotonic-coarse:    vdso: 1477 nsec/call
clock-getres-monotonic:    vdso: 135 nsec/call
clock-gettime-monotonic:    vdso: 283 nsec/call

With the series:

gettimeofday:    vdso: 271 nsec/call
clock-getres-realtime-coarse:    vdso: 159 nsec/call
clock-gettime-realtime-coarse:    vdso: 184 nsec/call
clock-getres-realtime:    vdso: 163 nsec/call
clock-gettime-realtime:    vdso: 281 nsec/call
clock-getres-boottime:    vdso: 169 nsec/call
clock-gettime-boottime:    vdso: 274 nsec/call
clock-getres-tai:    vdso: 163 nsec/call
clock-gettime-tai:    vdso: 277 nsec/call
clock-getres-monotonic-raw:    vdso: 166 nsec/call
clock-gettime-monotonic-raw:    vdso: 302 nsec/call
clock-getres-monotonic-coarse:    vdso: 159 nsec/call
clock-gettime-monotonic-coarse:    vdso: 184 nsec/call
clock-getres-monotonic:    vdso: 166 nsec/call
clock-gettime-monotonic:    vdso: 274 nsec/call

Christophe

  parent reply index

Thread overview: 26+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-01-16 17:58 Christophe Leroy
2020-01-16 17:58 ` [RFC PATCH v4 01/11] powerpc/64: Don't provide time functions in compat VDSO32 Christophe Leroy
2020-01-16 17:58 ` [RFC PATCH v4 02/11] powerpc/vdso: Switch VDSO to generic C implementation Christophe Leroy
2020-01-16 17:58 ` [RFC PATCH v4 03/11] lib: vdso: only read hrtimer_res when needed in __cvdso_clock_getres() Christophe Leroy
2020-01-16 17:58 ` [RFC PATCH v4 04/11] powerpc/vdso: simplify __get_datapage() Christophe Leroy
2020-01-16 17:58 ` [RFC PATCH v4 05/11] lib: vdso: allow arches to provide vdso data pointer Christophe Leroy
2020-01-16 17:58 ` [RFC PATCH v4 06/11] powerpc/vdso: provide inline alternative to __get_datapage() Christophe Leroy
2020-01-16 17:58 ` [RFC PATCH v4 07/11] powerpc/vdso: provide vdso data pointer from the ASM caller Christophe Leroy
2020-01-16 17:58 ` [RFC PATCH v4 08/11] lib: vdso: allow fixed clock mode Christophe Leroy
2020-01-16 20:13   ` Thomas Gleixner
2020-01-16 20:19     ` Andy Lutomirski
2020-01-16 21:07       ` Thomas Gleixner
2020-01-16 17:58 ` [RFC PATCH v4 09/11] powerpc/vdso: override __arch_vdso_capable() Christophe Leroy
2020-01-16 17:58 ` [RFC PATCH v4 10/11] lib: vdso: Allow arches to override the ns shift operation Christophe Leroy
2020-01-16 19:47   ` Andy Lutomirski
2020-01-16 19:57     ` Thomas Gleixner
2020-01-16 20:20       ` Andy Lutomirski
2020-01-29  7:14         ` Thomas Gleixner
2020-01-29  7:26           ` Christophe Leroy
2020-01-16 17:58 ` [RFC PATCH v4 11/11] powerpc/32: provide vdso_shift_ns() Christophe Leroy
2020-01-17  8:58 ` [RFC PATCH v4 00/11] powerpc: switch VDSO to C implementation Segher Boessenkool
2020-01-17  9:26   ` Christophe Leroy
2020-01-20 14:56   ` Christophe Leroy [this message]
2020-01-20 15:19     ` Segher Boessenkool
2020-01-20 17:08       ` Christophe Leroy
2020-01-20 17:27         ` Segher Boessenkool

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=3027b6d2-47a9-a871-7c52-050a5f9c6ab7@c-s.fr \
    --to=christophe.leroy@c-s.fr \
    --cc=arnd@arndb.de \
    --cc=benh@kernel.crashing.org \
    --cc=linux-arm-kernel@lists.infradead.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-mips@vger.kernel.org \
    --cc=linuxppc-dev@lists.ozlabs.org \
    --cc=luto@kernel.org \
    --cc=mpe@ellerman.id.au \
    --cc=nathanl@linux.ibm.com \
    --cc=paulus@samba.org \
    --cc=segher@kernel.crashing.org \
    --cc=tglx@linutronix.de \
    --cc=vincenzo.frascino@arm.com \
    --cc=x86@kernel.org \
    /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

Linux-MIPS Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/linux-mips/0 linux-mips/git/0.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 linux-mips linux-mips/ https://lore.kernel.org/linux-mips \
		linux-mips@vger.kernel.org
	public-inbox-index linux-mips

Example config snippet for mirrors

Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.kernel.vger.linux-mips


AGPL code for this site: git clone https://public-inbox.org/public-inbox.git