From: Vineet Gupta <Vineet.Gupta1@synopsys.com>
To: <linux-snps-arc@lists.infradead.org>
Cc: <linux-kernel@vger.kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
Vineet Gupta <Vineet.Gupta1@synopsys.com>
Subject: [PATCH 3/4] ARC: perf: avoid vmalloc backed mmap
Date: Tue, 7 Nov 2017 14:13:03 -0800 [thread overview]
Message-ID: <1510092784-19942-4-git-send-email-vgupta@synopsys.com> (raw)
In-Reply-To: <1510092784-19942-1-git-send-email-vgupta@synopsys.com>
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
next prev parent reply other threads:[~2017-11-07 22:13 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-11-07 22:13 [PATCH 0/4] ARC perf updates Vineet Gupta
2017-11-07 22:13 ` [PATCH 1/4] ARCv2: perf: tweak overflow interrupt Vineet Gupta
2017-11-07 22:13 ` [PATCH 2/4] ARCv2: perf: optimize given that num counters <= 32 Vineet Gupta
2017-11-07 22:13 ` Vineet Gupta [this message]
2017-11-07 22:13 ` [PATCH 4/4] ARCv2: entry: Reduce perf intr return path Vineet Gupta
2017-11-14 10:28 ` Peter Zijlstra
2017-11-14 23:01 ` Vineet Gupta
2017-11-15 10:18 ` Peter Zijlstra
2017-11-17 23:42 ` Vineet Gupta
2017-11-21 23:26 ` Vineet Gupta
2017-11-13 21:30 ` [PATCH 0/4] ARC perf updates Vineet Gupta
2017-11-21 22:09 ` Vineet Gupta
2017-11-21 23:13 ` Peter Zijlstra
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