Re: [PATCH 06/14] powerpc/64s: interrupt replay balance the return branch predictor
From: Gautham R Shenoy <hidden>
Date: 2017-06-12 14:41:50
On Mon, Jun 12, 2017 at 09:58:27AM +1000, Nicholas Piggin wrote:
The __replay_interrupt code is branched to with bl, but the caller is returned to directly with rfid from the interrupt. Instead return to a return stub that returns to the caller with blr, which should do better with the return predictor. Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Reviewed-by: Gautham R. Shenoy <redacted>
quoted hunk ↗ jump to hunk
--- arch/powerpc/kernel/exceptions-64s.S | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)diff --git a/arch/powerpc/kernel/exceptions-64s.S b/arch/powerpc/kernel/exceptions-64s.S index a04ee0d7f88e..d55201625ea3 100644 --- a/arch/powerpc/kernel/exceptions-64s.S +++ b/arch/powerpc/kernel/exceptions-64s.S@@ -1586,7 +1586,7 @@ _GLOBAL(__replay_interrupt) * we don't give a damn about, so we don't bother storing them. */ mfmsr r12 - mflr r11 + LOAD_REG_ADDR(r11, __replay_interrupt_return) mfcr r9 ori r12,r12,MSR_EE cmpwi r3,0x900@@ -1604,4 +1604,5 @@ FTR_SECTION_ELSE cmpwi r3,0xa00 beq doorbell_super_common_msgclr ALT_FTR_SECTION_END_IFSET(CPU_FTR_HVMODE) +__replay_interrupt_return: blr-- 2.11.0