Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S941071AbcJXOH1 (ORCPT ); Mon, 24 Oct 2016 10:07:27 -0400 Received: from mail-wm0-f67.google.com ([74.125.82.67]:33983 "EHLO mail-wm0-f67.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S939457AbcJXOHW (ORCPT ); Mon, 24 Oct 2016 10:07:22 -0400 From: Luca Abeni To: linux-kernel@vger.kernel.org Cc: Peter Zijlstra , Ingo Molnar , Juri Lelli , Claudio Scordino , Steven Rostedt , Luca Abeni Subject: [RFC v3 4/6] GRUB accounting Date: Mon, 24 Oct 2016 16:06:36 +0200 Message-Id: <1477317998-7487-5-git-send-email-luca.abeni@unitn.it> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1477317998-7487-1-git-send-email-luca.abeni@unitn.it> References: <1477317998-7487-1-git-send-email-luca.abeni@unitn.it> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1517 Lines: 45 According to the GRUB (Greedy Reclaimation of Unused Bandwidth) reclaiming algorithm, the runtime is not decreased as "dq = -dt", but as "dq = -Uact dt" (where Uact is the per-runqueue active utilization). Hence, this commit modifies the runtime accounting rule in update_curr_dl() to implement the GRUB rule. Signed-off-by: Luca Abeni --- kernel/sched/deadline.c | 14 ++++++++++++++ 1 file changed, 14 insertions(+) diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c index 4d3545b..fa10fcd 100644 --- a/kernel/sched/deadline.c +++ b/kernel/sched/deadline.c @@ -771,6 +771,19 @@ int dl_runtime_exceeded(struct sched_dl_entity *dl_se) extern bool sched_rt_bandwidth_account(struct rt_rq *rt_rq); /* + * This function implements the GRUB accounting rule: + * according to the GRUB reclaiming algorithm, the runtime is + * not decreased as "dq = -dt", but as "dq = -Uact dt", where + * Uact is the (per-runqueue) active utilization. + * Since rq->dl.running_bw contains Uact * 2^20, the result + * has to be shifted right by 20. + */ +u64 grub_reclaim(u64 delta, struct rq *rq) +{ + return (delta * rq->dl.running_bw) >> 20; +} + +/* * Update the current task's runtime statistics (provided it is still * a -deadline task and has not been removed from the dl_rq). */ @@ -812,6 +825,7 @@ static void update_curr_dl(struct rq *rq) sched_rt_avg_update(rq, delta_exec); + delta_exec = grub_reclaim(delta_exec, rq); dl_se->runtime -= delta_exec; throttle: -- 2.7.4