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Subject[PATCH 3/4] ARC: perf: avoid vmalloc backed mmap
Date
For non-alising Dcache, vmalloc is not needed.

vmalloc triggers additonal D-TLB Misses in the perf interrupt code path
making it slightly inefficient as evident from hackbench runs below.

| [ARCLinux]# perf stat -e dTLB-load-misses --repeat 5 hackbench
| Running with 10*40 (== 400) tasks.
| Time: 35.060
| ...
| Performance counter stats for 'hackbench' (5 runs):

Before: 399235 dTLB-load-misses ( +- 2.08% )
After : 397676 dTLB-load-misses ( +- 2.27% )

Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
---
arch/arc/Kconfig | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/arc/Kconfig b/arch/arc/Kconfig
index c84e67fdea09..f3cad98eeb8f 100644
--- a/arch/arc/Kconfig
+++ b/arch/arc/Kconfig
@@ -39,7 +39,7 @@ config ARC
select OF
select OF_EARLY_FLATTREE
select OF_RESERVED_MEM
- select PERF_USE_VMALLOC
+ select PERF_USE_VMALLOC if ARC_CACHE_VIPT_ALIASING
select HAVE_DEBUG_STACKOVERFLOW
select HAVE_GENERIC_DMA_COHERENT
select HAVE_KERNEL_GZIP
--
2.7.4
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