From: Christophe Leroy <christophe.leroy@c-s.fr>
To: Benjamin Herrenschmidt <benh@kernel.crashing.org>,
Paul Mackerras <paulus@samba.org>,
Michael Ellerman <mpe@ellerman.id.au>,
arnd@arndb.de, tglx@linutronix.de, vincenzo.frascino@arm.com,
luto@kernel.org
Cc: linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org,
linux-arm-kernel@lists.infradead.org, linux-mips@vger.kernel.org,
x86@kernel.org
Subject: [RFC PATCH v3 00/12] powerpc: switch VDSO to C implementation.
Date: Mon, 13 Jan 2020 17:08:38 +0000 (UTC) [thread overview]
Message-ID: <cover.1578934751.git.christophe.leroy@c-s.fr> (raw)
This is a third tentative to switch powerpc VDSO to generic C implementation.
This version should work on PPC64 (untested). VDSO32 for PPC64 is
impossible to build and has been de-activated, because the powerpc
ASM header files for C are not prepared to build 32 bits code with CONFIG_PPC64.
powerpc is a bit special for VDSO as well as system calls in the
way that it requires setting CR SO bit which cannot be done in C.
Therefore, entry/exit and fallback need to be performed in ASM.
On a powerpc8xx, with current powerpc/32 ASM VDSO:
gettimeofday: vdso: 737 nsec/call
clock-getres-realtime: vdso: 475 nsec/call
clock-gettime-realtime: vdso: 892 nsec/call
The first patch adds VDSO generic C support without any changes to common code.
Performance is as follows:
gettimeofday: vdso: 1379 nsec/call
clock-getres-realtime-coarse: vdso: 984 nsec/call
clock-gettime-realtime-coarse: vdso: 868 nsec/call
clock-getres-realtime: vdso: 922 nsec/call
clock-gettime-realtime: vdso: 1511 nsec/call
clock-getres-monotonic-raw: vdso: 968 nsec/call
clock-gettime-monotonic-raw: vdso: 1576 nsec/call
Then a few changes in the common code have allowed performance improvement. At
the end of the series we have:
gettimeofday: vdso: 899 nsec/call
clock-getres-realtime-coarse: vdso: 546 nsec/call
clock-gettime-realtime-coarse: vdso: 615 nsec/call
clock-getres-realtime: vdso: 545 nsec/call
clock-gettime-realtime: vdso: 1064 nsec/call
clock-getres-monotonic-raw: vdso: 546 nsec/call
clock-gettime-monotonic-raw: vdso: 1125 nsec/call
Christophe Leroy (12):
powerpc/64: Don't provide time functions in compat VDSO32
powerpc/vdso: Switch VDSO to generic C implementation.
lib: vdso: mark __cvdso_clock_getres() as static
lib: vdso: inline do_hres() and do_coarse()
lib: vdso: Avoid duplication in __cvdso_clock_getres()
lib: vdso: __iter_div_u64_rem() is suboptimal for 32 bit time
powerpc/vdso: simplify __get_datapage()
lib: vdso: allow arches to provide vdso data pointer
powerpc/vdso: provide inline alternative to __get_datapage()
powerpc/vdso: provide vdso data pointer from the ASM caller.
lib: vdso: split clock verification out of __arch_get_hw_counter()
powerpc/vdso: provide __arch_is_hw_counter_valid()
arch/powerpc/Kconfig | 2 +
arch/powerpc/include/asm/vdso/gettimeofday.h | 104 +++++++++++
arch/powerpc/include/asm/vdso/vsyscall.h | 25 +++
arch/powerpc/include/asm/vdso_datapage.h | 52 +++---
arch/powerpc/kernel/asm-offsets.c | 46 +----
arch/powerpc/kernel/time.c | 90 ----------
arch/powerpc/kernel/vdso.c | 58 ++----
arch/powerpc/kernel/vdso32/Makefile | 30 +++-
arch/powerpc/kernel/vdso32/datapage.S | 10 +-
arch/powerpc/kernel/vdso32/gettimeofday.S | 258 ++++-----------------------
arch/powerpc/kernel/vdso32/vdso32.lds.S | 9 +-
arch/powerpc/kernel/vdso32/vgettimeofday.c | 29 +++
arch/powerpc/kernel/vdso64/Makefile | 23 ++-
arch/powerpc/kernel/vdso64/datapage.S | 13 +-
arch/powerpc/kernel/vdso64/gettimeofday.S | 257 ++++----------------------
arch/powerpc/kernel/vdso64/vdso64.lds.S | 7 +-
arch/powerpc/kernel/vdso64/vgettimeofday.c | 29 +++
lib/vdso/gettimeofday.c | 130 +++++++++++---
18 files changed, 457 insertions(+), 715 deletions(-)
create mode 100644 arch/powerpc/include/asm/vdso/gettimeofday.h
create mode 100644 arch/powerpc/include/asm/vdso/vsyscall.h
create mode 100644 arch/powerpc/kernel/vdso32/vgettimeofday.c
create mode 100644 arch/powerpc/kernel/vdso64/vgettimeofday.c
--
2.13.3
next reply other threads:[~2020-01-13 17:08 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-13 17:08 Christophe Leroy [this message]
2020-01-13 17:08 ` [RFC PATCH v3 01/12] powerpc/64: Don't provide time functions in compat VDSO32 Christophe Leroy
2020-01-13 17:08 ` [RFC PATCH v3 02/12] powerpc/vdso: Switch VDSO to generic C implementation Christophe Leroy
2020-01-13 17:08 ` [RFC PATCH v3 03/12] lib: vdso: mark __cvdso_clock_getres() as static Christophe Leroy
2020-01-13 17:08 ` [RFC PATCH v3 04/12] lib: vdso: inline do_hres() and do_coarse() Christophe Leroy
2020-01-13 17:08 ` [RFC PATCH v3 05/12] lib: vdso: Avoid duplication in __cvdso_clock_getres() Christophe Leroy
2020-01-13 17:08 ` [RFC PATCH v3 06/12] lib: vdso: __iter_div_u64_rem() is suboptimal for 32 bit time Christophe Leroy
2020-01-14 11:31 ` Thomas Gleixner
2020-01-13 17:08 ` [RFC PATCH v3 07/12] powerpc/vdso: simplify __get_datapage() Christophe Leroy
2020-01-13 17:08 ` [RFC PATCH v3 08/12] lib: vdso: allow arches to provide vdso data pointer Christophe Leroy
2020-01-14 23:06 ` Thomas Gleixner
2020-01-15 6:15 ` Christophe Leroy
2020-01-16 9:16 ` Christophe Leroy
2020-01-16 10:35 ` Thomas Gleixner
2020-01-16 20:22 ` Andy Lutomirski
2020-01-13 17:08 ` [RFC PATCH v3 09/12] powerpc/vdso: provide inline alternative to __get_datapage() Christophe Leroy
2020-01-13 17:08 ` [RFC PATCH v3 10/12] powerpc/vdso: provide vdso data pointer from the ASM caller Christophe Leroy
2020-01-13 17:08 ` [RFC PATCH v3 11/12] lib: vdso: split clock verification out of __arch_get_hw_counter() Christophe Leroy
2020-01-13 17:08 ` [RFC PATCH v3 12/12] powerpc/vdso: provide __arch_is_hw_counter_valid() Christophe Leroy
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