From patchwork Fri May 19 14:41:12 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Anton Blanchard X-Patchwork-Id: 764704 Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Received: from lists.ozlabs.org (lists.ozlabs.org [103.22.144.68]) (using TLSv1.2 with cipher ADH-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 3wTrP26jpjz9s5L for ; Sat, 20 May 2017 00:42:14 +1000 (AEST) Received: from lists.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) by lists.ozlabs.org (Postfix) with ESMTP id 3wTrP25vLnzDqhN for ; Sat, 20 May 2017 00:42:14 +1000 (AEST) X-Original-To: linuxppc-dev@lists.ozlabs.org Delivered-To: linuxppc-dev@lists.ozlabs.org Received: from ozlabs.org (ozlabs.org [IPv6:2401:3900:2:1::2]) (using TLSv1.2 with cipher ADH-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 3wTrMx2JbjzDqf0 for ; Sat, 20 May 2017 00:41:17 +1000 (AEST) Received: by ozlabs.org (Postfix, from userid 1010) id 3wTrMx1RGMz9s7k; Sat, 20 May 2017 00:41:17 +1000 (AEST) From: Anton Blanchard To: benh@kernel.crashing.org, paulus@samba.org, mpe@ellerman.id.au, npiggin@gmail.com, mikey@neuling.org, cyrilbur@gmail.com Subject: [PATCH] powerpc/64: Use tick accounting by default Date: Sat, 20 May 2017 00:41:12 +1000 Message-Id: <20170519144112.15649-1-anton@ozlabs.org> X-Mailer: git-send-email 2.11.0 X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: linuxppc-dev@lists.ozlabs.org Errors-To: linuxppc-dev-bounces+patchwork-incoming=ozlabs.org@lists.ozlabs.org Sender: "Linuxppc-dev" From: Anton Blanchard ppc64 is the only architecture that turns on VIRT_CPU_ACCOUNTING_NATIVE by default. The overhead of this option is extremely high - a context switch microbenchmark using sched_yield() is almost 20% slower. To get finer grained user/hardirq/softirq statitics, the IRQ_TIME_ACCOUNTING option can be used instead, which has much lower overhead. As such, disable this option by default. If a user really wants it, they can still enable it manually. Signed-off-by: Anton Blanchard --- init/Kconfig | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) diff --git a/init/Kconfig b/init/Kconfig index 1d3475fc9496..a5c30acc1ede 100644 --- a/init/Kconfig +++ b/init/Kconfig @@ -342,8 +342,7 @@ config VIRT_CPU_ACCOUNTING choice prompt "Cputime accounting" - default TICK_CPU_ACCOUNTING if !PPC64 - default VIRT_CPU_ACCOUNTING_NATIVE if PPC64 + default TICK_CPU_ACCOUNTING # Kind of a stub config for the pure tick based cputime accounting config TICK_CPU_ACCOUNTING