From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756616AbdKGWNv (ORCPT ); Tue, 7 Nov 2017 17:13:51 -0500 Received: from smtprelay.synopsys.com ([198.182.47.9]:47210 "EHLO smtprelay.synopsys.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756438AbdKGWNW (ORCPT ); Tue, 7 Nov 2017 17:13:22 -0500 From: Vineet Gupta To: CC: , Peter Zijlstra , Vineet Gupta Subject: [PATCH 3/4] ARC: perf: avoid vmalloc backed mmap Date: Tue, 7 Nov 2017 14:13:03 -0800 Message-ID: <1510092784-19942-4-git-send-email-vgupta@synopsys.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1510092784-19942-1-git-send-email-vgupta@synopsys.com> References: <1510092784-19942-1-git-send-email-vgupta@synopsys.com> MIME-Version: 1.0 Content-Type: text/plain X-Originating-IP: [10.10.161.44] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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 --- 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