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https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
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f441882a52
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>
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| .. | ||
| boot | ||
| common | ||
| configs | ||
| crypto | ||
| firmware | ||
| include | ||
| kernel | ||
| kvm | ||
| lib | ||
| mach-actions | ||
| mach-alpine | ||
| mach-artpec | ||
| mach-asm9260 | ||
| mach-aspeed | ||
| mach-at91 | ||
| mach-axxia | ||
| mach-bcm | ||
| mach-berlin | ||
| mach-clps711x | ||
| mach-cns3xxx | ||
| mach-davinci | ||
| mach-digicolor | ||
| mach-dove | ||
| mach-ebsa110 | ||
| mach-efm32 | ||
| mach-ep93xx | ||
| mach-exynos | ||
| mach-footbridge | ||
| mach-gemini | ||
| mach-highbank | ||
| mach-hisi | ||
| mach-imx | ||
| mach-integrator | ||
| mach-iop13xx | ||
| mach-iop32x | ||
| mach-iop33x | ||
| mach-ixp4xx | ||
| mach-keystone | ||
| mach-ks8695 | ||
| mach-lpc18xx | ||
| mach-lpc32xx | ||
| mach-mediatek | ||
| mach-meson | ||
| mach-mmp | ||
| mach-moxart | ||
| mach-mv78xx0 | ||
| mach-mvebu | ||
| mach-mxs | ||
| mach-netx | ||
| mach-nomadik | ||
| mach-npcm | ||
| mach-nspire | ||
| mach-omap1 | ||
| mach-omap2 | ||
| mach-orion5x | ||
| mach-oxnas | ||
| mach-picoxcell | ||
| mach-prima2 | ||
| mach-pxa | ||
| mach-qcom | ||
| mach-realview | ||
| mach-rockchip | ||
| mach-rpc | ||
| mach-s3c24xx | ||
| mach-s3c64xx | ||
| mach-s5pv210 | ||
| mach-sa1100 | ||
| mach-shmobile | ||
| mach-socfpga | ||
| mach-spear | ||
| mach-sti | ||
| mach-stm32 | ||
| mach-sunxi | ||
| mach-tango | ||
| mach-tegra | ||
| mach-u300 | ||
| mach-uniphier | ||
| mach-ux500 | ||
| mach-versatile | ||
| mach-vexpress | ||
| mach-vt8500 | ||
| mach-w90x900 | ||
| mach-zx | ||
| mach-zynq | ||
| mm | ||
| net | ||
| nwfpe | ||
| oprofile | ||
| plat-iop | ||
| plat-omap | ||
| plat-orion | ||
| plat-pxa | ||
| plat-samsung | ||
| plat-versatile | ||
| probes | ||
| tools | ||
| vdso | ||
| vfp | ||
| xen | ||
| Kconfig | ||
| Kconfig-nommu | ||
| Kconfig.debug | ||
| Makefile | ||