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 [thread overview]
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
next prev parent reply other threads:[~2020-01-20 14:56 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-16 17:58 [RFC PATCH v4 00/11] powerpc: switch VDSO to C implementation 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
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