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authorNicholas Piggin <npiggin@gmail.com>2017-11-03 07:13:20 +0300
committerMichael Ellerman <mpe@ellerman.id.au>2017-11-06 14:46:15 +0300
commit9d2f510a66ec60411536b83dab831ee091c84307 (patch)
tree0c121b6385a2309189bbe1edda5b28815f7f8952 /arch/powerpc/kernel
parentb6b3755e9bec9c686a34ec81eacced0075370cbc (diff)
downloadlinux-9d2f510a66ec60411536b83dab831ee091c84307.tar.xz
powerpc/64s/idle: avoid POWER9 DD1 and DD2.0 ERAT workaround on DD2.1
DD2.1 does not have to flush the ERAT after a state-loss idle. Performance testing was done on a DD2.1 using only the stop0 idle state (the shallowest state which supports state loss), using context_switch selftest configured to ping-poing between two threads on the same core and two different cores. Performance improvement for same core is 7.0%, different cores is 14.8%. Reviewed-by: Vaidyanathan Srinivasan <svaidy@linux.vnet.ibm.com> Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Diffstat (limited to 'arch/powerpc/kernel')
-rw-r--r--arch/powerpc/kernel/idle_book3s.S2
1 files changed, 2 insertions, 0 deletions
diff --git a/arch/powerpc/kernel/idle_book3s.S b/arch/powerpc/kernel/idle_book3s.S
index 175d49f468af..d77766814090 100644
--- a/arch/powerpc/kernel/idle_book3s.S
+++ b/arch/powerpc/kernel/idle_book3s.S
@@ -542,7 +542,9 @@ pnv_restore_hyp_resource_arch300:
* then clear bit 60 in MMCRA to ensure the PMU starts running.
*/
blt cr3,1f
+BEGIN_FTR_SECTION
PPC_INVALIDATE_ERAT
+END_FTR_SECTION_IFSET(CPU_FTR_POWER9_DD1 | CPU_FTR_POWER9_DD20)
ld r1,PACAR1(r13)
mfspr r4,SPRN_MMCRA
ori r4,r4,(1 << (63-60))