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From: Nicholas Piggin <npiggin@gmail.com>
To: linuxppc-dev@lists.ozlabs.org
Cc: Nicholas Piggin <npiggin@gmail.com>,
	"Gautham R . Shenoy" <ego@linux.vnet.ibm.com>,
	"Shreyas B . Prabhu" <shreyas@linux.vnet.ibm.com>
Subject: [PATCH 06/14] powerpc/64s: interrupt replay balance the return branch predictor
Date: Mon, 12 Jun 2017 09:58:27 +1000	[thread overview]
Message-ID: <20170611235835.7400-7-npiggin@gmail.com> (raw)
In-Reply-To: <20170611235835.7400-1-npiggin@gmail.com>

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>
---
 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

  parent reply	other threads:[~2017-06-12  0:00 UTC|newest]

Thread overview: 42+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-06-11 23:58 [PATCH 00/14 v2] idle performance improvements Nicholas Piggin
2017-06-11 23:58 ` [PATCH 01/14] powerpc/64s: idle move soft interrupt mask logic into C code Nicholas Piggin
2017-06-12  8:37   ` Gautham R Shenoy
2017-06-12 14:46     ` Nicholas Piggin
2017-06-13  4:28       ` Gautham R Shenoy
2017-06-11 23:58 ` [PATCH 02/14] powerpc/64s: idle hotplug lazy-irq simplification Nicholas Piggin
2017-06-11 23:58 ` [PATCH 03/14] powerpc/64s: idle provide a default idle for POWER9 Nicholas Piggin
2017-06-12  8:53   ` Gautham R Shenoy
2017-06-12 14:46     ` Nicholas Piggin
2017-06-11 23:58 ` [PATCH 04/14] powerpc/64s: idle process interrupts from system reset wakeup Nicholas Piggin
2017-06-12  9:41   ` Gautham R Shenoy
2017-06-12 14:51     ` Nicholas Piggin
2017-06-11 23:58 ` [PATCH 05/14] powerpc/64s: msgclr when handling doorbell exceptions Nicholas Piggin
2017-06-12 14:38   ` Gautham R Shenoy
2017-06-11 23:58 ` Nicholas Piggin [this message]
2017-06-12 14:41   ` [PATCH 06/14] powerpc/64s: interrupt replay balance the return branch predictor Gautham R Shenoy
2017-06-13  9:51   ` Michael Ellerman
2017-06-13 11:09     ` Nicholas Piggin
2017-06-11 23:58 ` [PATCH 07/14] powerpc/64s: idle branch to handler with virtual mode offset Nicholas Piggin
2017-06-11 23:58 ` [PATCH 08/14] powerpc/64s: idle avoid SRR usage in idle sleep/wake paths Nicholas Piggin
2017-06-13 10:25   ` Gautham R Shenoy
2017-06-13 10:45     ` Nicholas Piggin
2017-06-11 23:58 ` [PATCH 09/14] powerpc/64s: idle hmi wakeup is unlikely Nicholas Piggin
2017-06-12 15:03   ` Gautham R Shenoy
2017-06-11 23:58 ` [PATCH 10/14] powerpc/64s: cpuidle set polling before enabling irqs Nicholas Piggin
2017-06-12 15:10   ` Gautham R Shenoy
2017-06-12 15:20     ` Nicholas Piggin
2017-06-11 23:58 ` [PATCH 11/14] powerpc/64s: cpuidle read mostly for common globals Nicholas Piggin
2017-06-12 15:30   ` Gautham R Shenoy
2017-06-12 17:50     ` Vaidyanathan Srinivasan
2017-06-11 23:58 ` [PATCH 12/14] powerpc/64s: cpuidle no memory barrier after break from idle Nicholas Piggin
2017-06-12 17:48   ` Vaidyanathan Srinivasan
2017-06-13 12:47     ` Nicholas Piggin
2017-06-11 23:58 ` [PATCH 13/14] powerpc/64: runlatch CTRL[RUN] set optimisation Nicholas Piggin
2017-06-12 17:11   ` Vaidyanathan Srinivasan
2017-06-13 10:04     ` Michael Ellerman
2017-06-13 11:56       ` Nicholas Piggin
2017-06-13 13:45       ` Benjamin Herrenschmidt
2017-06-14  3:34         ` Michael Ellerman
2017-06-11 23:58 ` [PATCH 14/14] powerpc/64s: idle runlatch switch is done with MSR[EE]=0 Nicholas Piggin
2017-06-12 17:00   ` Vaidyanathan Srinivasan
  -- strict thread matches above, loose matches on Subject: below --
2017-06-08 15:50 [PATCH 00/14] idle performance improvements Nicholas Piggin
2017-06-08 15:51 ` [PATCH 06/14] powerpc/64s: interrupt replay balance the return branch predictor Nicholas Piggin

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