linux/arch/powerpc
Anton Blanchard 152d523e63 powerpc: Create context switch helpers save_sprs() and restore_sprs()
Move all our context switch SPR save and restore code into two
helpers. We do a few optimisations:

- Group all mfsprs and all mtsprs. In many cases an mtspr sets a
scoreboarding bit that an mfspr waits on, so the current practise of
mfspr A; mtspr A; mfpsr B; mtspr B is the worst scheduling we can
do.

- SPR writes are slow, so check that the value is changing before
writing it.

A context switch microbenchmark using yield():

http://ozlabs.org/~anton/junkcode/context_switch2.c

./context_switch2 --test=yield 0 0

shows an improvement of almost 10% on POWER8.

Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2015-12-01 13:52:24 +11:00
..
boot powerpc/boot: allow wrapper to work on non-english system 2015-11-26 22:11:16 +11:00
configs powerpc updates for 4.4 2015-11-05 23:38:43 -08:00
crypto crypto: powerpc/md5 - use md5 IV MD5_HX instead of their raw value 2015-05-18 12:20:20 +08:00
include powerpc: Create context switch helpers save_sprs() and restore_sprs() 2015-12-01 13:52:24 +11:00
kernel powerpc: Create context switch helpers save_sprs() and restore_sprs() 2015-12-01 13:52:24 +11:00
kvm Four changes: 2015-11-12 14:34:06 -08:00
lib powerpc32: memset: only use dcbz once cache is enabled 2015-09-17 10:36:53 +10:00
math-emu
mm powerpc updates for 4.4 2015-11-05 23:38:43 -08:00
net ebpf: migrate bpf_prog's flags to bitfield 2015-10-03 05:02:39 -07:00
oprofile powerpc: Remove mtmsrd(), use existing mtmsr() 2015-07-13 15:47:28 +10:00
perf powerpc updates for 4.4 2015-11-05 23:38:43 -08:00
platforms powerpc: Standardise on NR_syscalls rather than __NR_syscalls. 2015-11-26 22:11:17 +11:00
sysdev powerpc/axonram: Fix module autoload for OF platform driver 2015-11-26 22:11:18 +11:00
xmon powerpc/xmon: Add some more elements to the existing PACA dump list 2015-10-15 20:32:02 +11:00
Kconfig powerpc/book3e-64: Enable kexec 2015-10-27 18:13:30 -05:00
Kconfig.debug powerpc: Make STRICT_MM_TYPECHECKS a config option 2015-05-11 19:53:59 +10:00
Makefile powerpc/cell: Drop CONFIG_TUNE_CELL in favour of CONFIG_CELL_CPU 2015-10-19 19:51:18 +11:00
relocs_check.sh powerpc: Convert relocs_check to a shell script using grep 2015-03-23 14:47:39 +11:00