From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753325AbdJSMCi (ORCPT ); Thu, 19 Oct 2017 08:02:38 -0400 Received: from 20pmail.ess.barracuda.com ([64.235.154.233]:40070 "EHLO 20pmail.ess.barracuda.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752259AbdJSMCh (ORCPT ); Thu, 19 Oct 2017 08:02:37 -0400 From: Matt Redfearn To: Thomas Gleixner , Daniel Lezcano CC: James Hogan , , "Matt Redfearn" , Subject: [PATCH V2 3/3] clocksource: mips-gic-timer: Add fastpath for local timer updates Date: Thu, 19 Oct 2017 12:55:35 +0100 Message-ID: <1508414135-29123-3-git-send-email-matt.redfearn@mips.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1508414135-29123-1-git-send-email-matt.redfearn@mips.com> References: <1508414135-29123-1-git-send-email-matt.redfearn@mips.com> MIME-Version: 1.0 Content-Type: text/plain X-Originating-IP: [10.150.130.83] X-BESS-ID: 1508414543-321457-1461-58252-14 X-BESS-VER: 2017.12-r1710102214 X-BESS-Apparent-Source-IP: 12.201.5.28 X-BESS-Outbound-Spam-Score: 0.00 X-BESS-Outbound-Spam-Report: Code version 3.2, rules version 3.2.2.186115 Rule breakdown below pts rule name description ---- ---------------------- -------------------------------- 0.00 BSF_BESS_OUTBOUND META: BESS Outbound X-BESS-Outbound-Spam-Status: SCORE=0.00 using account:ESS59374 scores of KILL_LEVEL=7.0 tests=BSF_BESS_OUTBOUND X-BESS-BRTS-Status: 1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Always accessing the compare register via the CM redirect region is (relatively) slow. If the timer being updated is the current CPUs then this can be shortcutted by writing to the CM VP local region. Signed-off-by: Matt Redfearn --- drivers/clocksource/mips-gic-timer.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) diff --git a/drivers/clocksource/mips-gic-timer.c b/drivers/clocksource/mips-gic-timer.c index 8e8e3aa25b3f..e8dee5491227 100644 --- a/drivers/clocksource/mips-gic-timer.c +++ b/drivers/clocksource/mips-gic-timer.c @@ -39,14 +39,19 @@ static u64 notrace gic_read_count(void) static int gic_next_event(unsigned long delta, struct clock_event_device *evt) { + int cpu = cpumask_first(evt->cpumask); unsigned long flags; u64 cnt; int res; cnt = gic_read_count(); cnt += (u64)delta; - write_gic_vl_other(mips_cm_vp_id(cpumask_first(evt->cpumask))); - write_gic_vo_compare(cnt); + if (cpu == raw_smp_processor_id()) { + write_gic_vl_compare(cnt); + } else { + write_gic_vl_other(mips_cm_vp_id(cpu)); + write_gic_vo_compare(cnt); + } res = ((int)(gic_read_count() - cnt) >= 0) ? -ETIME : 0; return res; } -- 2.7.4