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| author | Robin Getz <robin.getz@analog.com> | 2010-05-04 14:59:21 +0000 |
|---|---|---|
| committer | Mike Frysinger <vapier@gentoo.org> | 2010-05-22 14:19:11 -0400 |
| commit | 648eee52ccdc623e21b920d6048e93490a4860a7 (patch) | |
| tree | 1d106f156abb6c7a0169a392f4856cd63893e079 /arch/blackfin/lib/memset.S | |
| parent | c70dcabc8eba18113a4735e7b1bd09f7493e38f0 (diff) | |
| download | kernel_samsung_smdk4412-648eee52ccdc623e21b920d6048e93490a4860a7.zip kernel_samsung_smdk4412-648eee52ccdc623e21b920d6048e93490a4860a7.tar.gz kernel_samsung_smdk4412-648eee52ccdc623e21b920d6048e93490a4860a7.tar.bz2 | |
Blackfin: optimize strncpy a bit
Add a little strncpy optimization which can easily cut boot time by 20%.
When the kernel is booting with initramfs, it builds up the filesystem
from a cpio archive by calling strncpy_from_user() via fs/namei.c's
do_getname() on every file in the archive (which can be lots) with a
length of PATH_MAX (1024). This causes the dest of the strncpy to be
padded with many NUL bytes.
This optimization mostly causes these NUL bytes to be padded with a call
to memset() which is already optimized for filling memory quickly, but
the hardware loop helps a little bit as well.
Boot time measured with 'loglevel=0' so UART speed doesn't get in the way.
Signed-off-by: Robin Getz <robin.getz@analog.com>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
Diffstat (limited to 'arch/blackfin/lib/memset.S')
| -rw-r--r-- | arch/blackfin/lib/memset.S | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/arch/blackfin/lib/memset.S b/arch/blackfin/lib/memset.S index c30d99b..eab1bef 100644 --- a/arch/blackfin/lib/memset.S +++ b/arch/blackfin/lib/memset.S @@ -20,6 +20,7 @@ * R1 = filler byte * R2 = count * Favours word aligned data. + * The strncpy assumes that I0 and I1 are not used in this function */ ENTRY(_memset) |