Commit 82385732 authored by Vineet Gupta's avatar Vineet Gupta
Browse files

ARC: perf: avoid vmalloc backed mmap 



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% )

Acked-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: default avatarVineet Gupta <vgupta@synopsys.com>
parent 5b9027d6

arch/arc/Kconfig

+1 −1
Original line number Diff line number Diff line
@@ -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

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