For many sun4v processor types, reading or writing a privileged register
has a latency of 40 to 70 cycles. Use a combination of the low-latency
allclean, otherw, normalw, and nop instructions in etrap and rtrap to
replace 2 rdpr and 5 wrpr instructions and improve etrap/rtrap
performance. allclean, otherw, and normalw are available on NG2 and
later processors.
The average ticks to execute the flush windows trap ("ta 0x3") with and
without this patch on select platforms:
CPU Not patched Patched % Latency Reduction
NG2 1762 1558 -11.58
NG4 3619 3204 -11.47
M7 3015 2624 -12.97
SPARC64-X 829 770 -7.12
Signed-off-by: Anthony Yznaga <anthony.yznaga@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Move that sucker to just before TI_FPDEPTH and replace stb with sth in
etrap_save(). Take current_ds to its old place, so that we don't push
wsaved into TI_... flags. That allows to lose clearing syscall_noerror
on return from syscall.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
o Move all files from sparc64/kernel/ to sparc/kernel
- rename as appropriate
o Update sparc/Makefile to the changes
o Update sparc/kernel/Makefile to include the sparc64 files
NOTE: This commit changes link order on sparc64!
Link order had to change for either of sparc32 and sparc64.
And assuming sparc64 see more testing than sparc32 change link
order on sparc64 where issues will be caught faster.
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
