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Nicolas Pitre c626e3f5ca [ARM] alternative copy_to_user: more precise fallback threshold 
Previous size thresholds were guessed from various user space benchmarks
using a kernel with and without the alternative uaccess option.  This
is however not as precise as a kernel based test to measure the real
speed of each method.

This adds a simple test bench to show the time needed for each method.
With this, the optimal size treshold for the alternative implementation
can be determined with more confidence.  It appears that the optimal
threshold for both copy_to_user and clear_user is around 64 bytes. This
is not a surprise knowing that the memcpy and memset implementations
need at least 64 bytes to achieve maximum throughput.

One might suggest that such test be used to determine the optimal
threshold at run time instead, but results are near enough to 64 on
tested targets concerned by this alternative copy_to_user implementation,
so adding some overhead associated with a variable threshold is probably
not worth it for now.

Signed-off-by: Nicolas Pitre <nico@marvell.com>
2009-05-30 01:10:15 -04:00
..
ashldi3.S [ARM] 5227/1: Add the ENDPROC declarations to the .S files 2008-09-01 12:06:34 +01:00
ashrdi3.S [ARM] 5227/1: Add the ENDPROC declarations to the .S files 2008-09-01 12:06:34 +01:00
backtrace.S [ARM] 5227/1: Add the ENDPROC declarations to the .S files 2008-09-01 12:06:34 +01:00
bitops.h [ARM] spelling fixes 2007-05-20 20:10:32 +01:00
changebit.S [ARM] 5227/1: Add the ENDPROC declarations to the .S files 2008-09-01 12:06:34 +01:00
clear_user.S [ARM] allow for alternative __copy_to_user/__clear_user implementations 2009-05-29 22:34:45 -04:00
clearbit.S [ARM] 5227/1: Add the ENDPROC declarations to the .S files 2008-09-01 12:06:34 +01:00
copy_from_user.S [ARM] 5227/1: Add the ENDPROC declarations to the .S files 2008-09-01 12:06:34 +01:00
copy_page.S [ARM] 5227/1: Add the ENDPROC declarations to the .S files 2008-09-01 12:06:34 +01:00
copy_template.S [ARM] cache align destination pointer when copying memory for some processors 2008-06-22 22:44:38 +02:00
copy_to_user.S [ARM] allow for alternative __copy_to_user/__clear_user implementations 2009-05-29 22:34:45 -04:00
csumipv6.S [ARM] 5227/1: Add the ENDPROC declarations to the .S files 2008-09-01 12:06:34 +01:00
csumpartial.S [ARM] 5227/1: Add the ENDPROC declarations to the .S files 2008-09-01 12:06:34 +01:00
csumpartialcopy.S [ARM] 5231/1: Do not save the frame pointer in the csum_partial_copy_* functions 2008-09-01 12:06:35 +01:00
csumpartialcopygeneric.S [ARM] 5227/1: Add the ENDPROC declarations to the .S files 2008-09-01 12:06:34 +01:00
csumpartialcopyuser.S [ARM] 5231/1: Do not save the frame pointer in the csum_partial_copy_* functions 2008-09-01 12:06:35 +01:00
delay.S [ARM] 5227/1: Add the ENDPROC declarations to the .S files 2008-09-01 12:06:34 +01:00
div64.S [ARM] 5227/1: Add the ENDPROC declarations to the .S files 2008-09-01 12:06:34 +01:00
ecard.S [ARM] Move include/asm-arm/arch-* to arch/arm/*/include/mach 2008-08-07 09:55:48 +01:00
findbit.S [ARM] 5227/1: Add the ENDPROC declarations to the .S files 2008-09-01 12:06:34 +01:00
floppydma.S
getuser.S [ARM] 5227/1: Add the ENDPROC declarations to the .S files 2008-09-01 12:06:34 +01:00
io-acorn.S
io-readsb.S [ARM] 5227/1: Add the ENDPROC declarations to the .S files 2008-09-01 12:06:34 +01:00
io-readsl.S [ARM] 5227/1: Add the ENDPROC declarations to the .S files 2008-09-01 12:06:34 +01:00
io-readsw-armv3.S [ARM] Move include/asm-arm/arch-* to arch/arm/*/include/mach 2008-08-07 09:55:48 +01:00
io-readsw-armv4.S [ARM] 5227/1: Add the ENDPROC declarations to the .S files 2008-09-01 12:06:34 +01:00
io-shark.c
io-writesb.S [ARM] 5227/1: Add the ENDPROC declarations to the .S files 2008-09-01 12:06:34 +01:00
io-writesl.S [ARM] 5227/1: Add the ENDPROC declarations to the .S files 2008-09-01 12:06:34 +01:00
io-writesw-armv3.S [ARM] Move include/asm-arm/arch-* to arch/arm/*/include/mach 2008-08-07 09:55:48 +01:00
io-writesw-armv4.S [ARM] 5227/1: Add the ENDPROC declarations to the .S files 2008-09-01 12:06:34 +01:00
lib1funcs.S [ARM] 5227/1: Add the ENDPROC declarations to the .S files 2008-09-01 12:06:34 +01:00
lshrdi3.S [ARM] 5227/1: Add the ENDPROC declarations to the .S files 2008-09-01 12:06:34 +01:00
Makefile [ARM] alternative copy_to_user/clear_user implementation 2009-05-29 22:36:45 -04:00
memchr.S [ARM] 5227/1: Add the ENDPROC declarations to the .S files 2008-09-01 12:06:34 +01:00
memcpy.S [ARM] 5227/1: Add the ENDPROC declarations to the .S files 2008-09-01 12:06:34 +01:00
memmove.S [ARM] 5227/1: Add the ENDPROC declarations to the .S files 2008-09-01 12:06:34 +01:00
memset.S [ARM] remove memzero() 2008-11-27 12:37:59 +00:00
memzero.S [ARM] 5227/1: Add the ENDPROC declarations to the .S files 2008-09-01 12:06:34 +01:00
muldi3.S [ARM] 5227/1: Add the ENDPROC declarations to the .S files 2008-09-01 12:06:34 +01:00
putuser.S [ARM] 5227/1: Add the ENDPROC declarations to the .S files 2008-09-01 12:06:34 +01:00
setbit.S [ARM] 5227/1: Add the ENDPROC declarations to the .S files 2008-09-01 12:06:34 +01:00
sha1.S Merge branch 'ptebits' into devel 2008-10-09 21:31:56 +01:00
strchr.S [ARM] 5227/1: Add the ENDPROC declarations to the .S files 2008-09-01 12:06:34 +01:00
strncpy_from_user.S [ARM] 5227/1: Add the ENDPROC declarations to the .S files 2008-09-01 12:06:34 +01:00
strnlen_user.S [ARM] 5227/1: Add the ENDPROC declarations to the .S files 2008-09-01 12:06:34 +01:00
strrchr.S [ARM] 5227/1: Add the ENDPROC declarations to the .S files 2008-09-01 12:06:34 +01:00
testchangebit.S [ARM] 5227/1: Add the ENDPROC declarations to the .S files 2008-09-01 12:06:34 +01:00
testclearbit.S [ARM] 5227/1: Add the ENDPROC declarations to the .S files 2008-09-01 12:06:34 +01:00
testsetbit.S [ARM] 5227/1: Add the ENDPROC declarations to the .S files 2008-09-01 12:06:34 +01:00
uaccess_with_memcpy.c [ARM] alternative copy_to_user: more precise fallback threshold 2009-05-30 01:10:15 -04:00
uaccess.S [ARM] 5227/1: Add the ENDPROC declarations to the .S files 2008-09-01 12:06:34 +01:00
ucmpdi2.S [ARM] 5227/1: Add the ENDPROC declarations to the .S files 2008-09-01 12:06:34 +01:00