From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933068AbaJUOca (ORCPT ); Tue, 21 Oct 2014 10:32:30 -0400 Received: from bombadil.infradead.org ([198.137.202.9]:59037 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932702AbaJUOc2 (ORCPT ); Tue, 21 Oct 2014 10:32:28 -0400 Date: Tue, 21 Oct 2014 16:32:21 +0200 From: Peter Zijlstra To: Yuyang Du Cc: mingo@redhat.com, linux-kernel@vger.kernel.org, pjt@google.com, bsegall@google.com, arjan.van.de.ven@intel.com, len.brown@intel.com, rafael.j.wysocki@intel.com, alan.cox@intel.com, mark.gross@intel.com, fengguang.wu@intel.com Subject: Re: [RESEND PATCH 2/3 v5] sched: Rewrite per entity runnable load average tracking Message-ID: <20141021143221.GZ23531@worktop.programming.kicks-ass.net> References: <1412907717-2871-1-git-send-email-yuyang.du@intel.com> <1412907717-2871-3-git-send-email-yuyang.du@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1412907717-2871-3-git-send-email-yuyang.du@intel.com> User-Agent: Mutt/1.5.22.1 (2013-10-16) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Oct 10, 2014 at 10:21:56AM +0800, Yuyang Du wrote: > +static __always_inline u64 decay_load(u64 val, u64 n) > +{ > + if (likely(val <= UINT_MAX)) > + return decay_load32(val, n); > + > + return mul_u64_u32_shr(val, decay_load32(1 << 15, n), 15); > +} This still doesn't make any sense, why not put that mul_u64_u32_shr() into decay_load() and be done with it? --- kernel/sched/fair.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index b78280c59b46..67c08d4a3df8 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -2231,9 +2231,8 @@ static __always_inline u64 decay_load(u64 val, u64 n) local_n %= LOAD_AVG_PERIOD; } - val *= runnable_avg_yN_inv[local_n]; - /* We don't use SRR here since we always want to round down. */ - return val >> 32; + val = mul_u64_u32_shr(val, runnable_avg_yN_inv[local_n], 32); + return val; } /*