diff options
| author | Vincent Whitchurch <vincent.whitchurch@axis.com> | 2018-11-09 10:09:48 +0100 |
|---|---|---|
| committer | Russell King <rmk+kernel@armlinux.org.uk> | 2018-11-12 10:51:59 +0000 |
| commit | f441882a5229ffaef61a47bccd4518f7e2749cbc (patch) | |
| tree | 551bb462ee92122edfbaf07c35b42791b651abbf /arch/arm/include/asm/assembler.h | |
| parent | bc2eca9a682881f9da3cc7e2d75b752e549a134d (diff) | |
ARM: 8812/1: Optimise copy_{from/to}_user for !CPU_USE_DOMAINS
ARMv6+ processors do not use CONFIG_CPU_USE_DOMAINS and use privileged
ldr/str instructions in copy_{from/to}_user. They are currently
unnecessarily using single ldr/str instructions and can use ldm/stm
instructions instead like memcpy does (but with appropriate fixup
tables).
This speeds up a "dd if=foo of=bar bs=32k" on a tmpfs filesystem by
about 4% on my Cortex-A9.
before:134217728 bytes (128.0MB) copied, 0.543848 seconds, 235.4MB/s
before:134217728 bytes (128.0MB) copied, 0.538610 seconds, 237.6MB/s
before:134217728 bytes (128.0MB) copied, 0.544356 seconds, 235.1MB/s
before:134217728 bytes (128.0MB) copied, 0.544364 seconds, 235.1MB/s
before:134217728 bytes (128.0MB) copied, 0.537130 seconds, 238.3MB/s
before:134217728 bytes (128.0MB) copied, 0.533443 seconds, 240.0MB/s
before:134217728 bytes (128.0MB) copied, 0.545691 seconds, 234.6MB/s
before:134217728 bytes (128.0MB) copied, 0.534695 seconds, 239.4MB/s
before:134217728 bytes (128.0MB) copied, 0.540561 seconds, 236.8MB/s
before:134217728 bytes (128.0MB) copied, 0.541025 seconds, 236.6MB/s
after:134217728 bytes (128.0MB) copied, 0.520445 seconds, 245.9MB/s
after:134217728 bytes (128.0MB) copied, 0.527846 seconds, 242.5MB/s
after:134217728 bytes (128.0MB) copied, 0.519510 seconds, 246.4MB/s
after:134217728 bytes (128.0MB) copied, 0.527231 seconds, 242.8MB/s
after:134217728 bytes (128.0MB) copied, 0.525030 seconds, 243.8MB/s
after:134217728 bytes (128.0MB) copied, 0.524236 seconds, 244.2MB/s
after:134217728 bytes (128.0MB) copied, 0.523659 seconds, 244.4MB/s
after:134217728 bytes (128.0MB) copied, 0.525018 seconds, 243.8MB/s
after:134217728 bytes (128.0MB) copied, 0.519249 seconds, 246.5MB/s
after:134217728 bytes (128.0MB) copied, 0.518527 seconds, 246.9MB/s
Reviewed-by: Nicolas Pitre <nico@linaro.org>
Signed-off-by: Vincent Whitchurch <vincent.whitchurch@axis.com>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Diffstat (limited to 'arch/arm/include/asm/assembler.h')
| -rw-r--r-- | arch/arm/include/asm/assembler.h | 6 |
1 files changed, 4 insertions, 2 deletions
diff --git a/arch/arm/include/asm/assembler.h b/arch/arm/include/asm/assembler.h index 88286dd483ff..28a48e0d4cca 100644 --- a/arch/arm/include/asm/assembler.h +++ b/arch/arm/include/asm/assembler.h @@ -243,13 +243,15 @@ .endm #endif -#define USER(x...) \ +#define USERL(l, x...) \ 9999: x; \ .pushsection __ex_table,"a"; \ .align 3; \ - .long 9999b,9001f; \ + .long 9999b,l; \ .popsection +#define USER(x...) USERL(9001f, x) + #ifdef CONFIG_SMP #define ALT_SMP(instr...) \ 9998: instr |