Messages in this thread Patch in this message | | | From | Vineet Gupta <> | Subject | [PATCH 3/4] ARC: perf: avoid vmalloc backed mmap | Date | Tue, 7 Nov 2017 14:13:03 -0800 |
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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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