From patchwork Tue Mar 29 13:44:09 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Joao Martins X-Patchwork-Id: 8687281 Return-Path: X-Original-To: patchwork-xen-devel@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork2.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork2.web.kernel.org (Postfix) with ESMTP id 91936C0553 for ; Tue, 29 Mar 2016 13:46:55 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 808C2202F8 for ; Tue, 29 Mar 2016 13:46:54 +0000 (UTC) Received: from lists.xenproject.org (lists.xenproject.org [192.237.175.120]) (using TLSv1.2 with cipher AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 8894420154 for ; Tue, 29 Mar 2016 13:46:53 +0000 (UTC) Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.84_2) (envelope-from ) id 1aktwj-0007Qd-T6; Tue, 29 Mar 2016 13:44:37 +0000 Received: from mail6.bemta3.messagelabs.com ([195.245.230.39]) by lists.xenproject.org with esmtp (Exim 4.84_2) (envelope-from ) id 1aktwj-0007QN-C8 for xen-devel@lists.xen.org; Tue, 29 Mar 2016 13:44:37 +0000 Received: from [85.158.137.68] by server-13.bemta-3.messagelabs.com id 35/7C-03443-4C68AF65; Tue, 29 Mar 2016 13:44:36 +0000 X-Env-Sender: joao.m.martins@oracle.com X-Msg-Ref: server-12.tower-31.messagelabs.com!1459259074!15150621!1 X-Originating-IP: [156.151.31.81] X-SpamReason: No, hits=0.0 required=7.0 tests=sa_preprocessor: VHJ1c3RlZCBJUDogMTU2LjE1MS4zMS44MSA9PiAyODgzMzk=\n X-StarScan-Received: X-StarScan-Version: 8.11; banners=-,-,- X-VirusChecked: Checked Received: (qmail 26012 invoked from network); 29 Mar 2016 13:44:35 -0000 Received: from userp1040.oracle.com (HELO userp1040.oracle.com) (156.151.31.81) by server-12.tower-31.messagelabs.com with DHE-RSA-AES256-GCM-SHA384 encrypted SMTP; 29 Mar 2016 13:44:35 -0000 Received: from aserv0021.oracle.com (aserv0021.oracle.com [141.146.126.233]) by userp1040.oracle.com (Sentrion-MTA-4.3.2/Sentrion-MTA-4.3.2) with ESMTP id u2TDiUE4012413 (version=TLSv1 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK); Tue, 29 Mar 2016 13:44:31 GMT Received: from aserv0121.oracle.com (aserv0121.oracle.com [141.146.126.235]) by aserv0021.oracle.com (8.13.8/8.13.8) with ESMTP id u2TDiU7r013622 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK); Tue, 29 Mar 2016 13:44:30 GMT Received: from abhmp0016.oracle.com (abhmp0016.oracle.com [141.146.116.22]) by aserv0121.oracle.com (8.13.8/8.13.8) with ESMTP id u2TDiTXA007781; Tue, 29 Mar 2016 13:44:29 GMT Received: from localhost.localdomain (/193.126.154.29) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Tue, 29 Mar 2016 06:44:29 -0700 From: Joao Martins To: xen-devel@lists.xen.org Date: Tue, 29 Mar 2016 14:44:09 +0100 Message-Id: <1459259051-4943-5-git-send-email-joao.m.martins@oracle.com> X-Mailer: git-send-email 2.1.4 In-Reply-To: <1459259051-4943-1-git-send-email-joao.m.martins@oracle.com> References: <1459259051-4943-1-git-send-email-joao.m.martins@oracle.com> X-Source-IP: aserv0021.oracle.com [141.146.126.233] Cc: Andrew Cooper , Joao Martins , Keir Fraser , Jan Beulich Subject: [Xen-devel] [PATCH v2 4/6] x86/time: streamline platform time init on plt_init() X-BeenThere: xen-devel@lists.xen.org X-Mailman-Version: 2.1.18 Precedence: list List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Errors-To: xen-devel-bounces@lists.xen.org Sender: "Xen-devel" X-Spam-Status: No, score=-4.2 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_MED, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP And use to initialize platform time solely for clocksource=tsc, as opposed to initializing platform overflow timer, which would only fire in ~180 years (on 2.2 Ghz Broadwell processor). Signed-off-by: Joao Martins Reviewed-by: Andrew Cooper --- Cc: Keir Fraser Cc: Jan Beulich Cc: Andrew Cooper Changes since v1: - Remove initialisation to 0. - Remove assignment and return mix. - Fix the style on plt_overflow_period calculation. Changes since RFC: - Move clocksource_is_tsc variable to this patch. - s/1000000000/SECONDS(1) --- xen/arch/x86/time.c | 44 ++++++++++++++++++++++++++++++++++++-------- 1 file changed, 36 insertions(+), 8 deletions(-) diff --git a/xen/arch/x86/time.c b/xen/arch/x86/time.c index 2602dda..9cadfcb 100644 --- a/xen/arch/x86/time.c +++ b/xen/arch/x86/time.c @@ -434,6 +434,7 @@ uint64_t ns_to_acpi_pm_tick(uint64_t ns) /************************************************************ * PLATFORM TIMER 4: TSC */ +static bool_t clocksource_is_tsc; static u64 tsc_freq; static unsigned long tsc_max_warp; static void tsc_check_reliability(void); @@ -466,6 +467,8 @@ static int __init init_tsctimer(struct platform_timesource *pts) } pts->frequency = tsc_freq; + clocksource_is_tsc = tsc_reliable; + return tsc_reliable; } @@ -516,17 +519,31 @@ static s_time_t __read_platform_stime(u64 platform_time) return (stime_platform_stamp + scale_delta(diff, &plt_scale)); } +static void __plt_init(void) +{ + u64 count; + + ASSERT(spin_is_locked(&platform_timer_lock)); + count = plt_src.read_counter(); + plt_stamp64 += (count - plt_stamp) & plt_mask; + plt_stamp = count; +} + +static void plt_init(void) +{ + spin_lock_irq(&platform_timer_lock); + __plt_init(); + spin_unlock_irq(&platform_timer_lock); +} + static void plt_overflow(void *unused) { int i; - u64 count; s_time_t now, plt_now, plt_wrap; spin_lock_irq(&platform_timer_lock); - count = plt_src.read_counter(); - plt_stamp64 += (count - plt_stamp) & plt_mask; - plt_stamp = count; + __plt_init(); now = NOW(); plt_wrap = __read_platform_stime(plt_stamp64); @@ -621,11 +638,22 @@ static int __init try_platform_timer(struct platform_timesource *pts) set_time_scale(&plt_scale, pts->frequency); - plt_overflow_period = scale_delta( - 1ull << (pts->counter_bits - 1), &plt_scale); - init_timer(&plt_overflow_timer, plt_overflow, NULL, 0); plt_src = *pts; - plt_overflow(NULL); + + if ( clocksource_is_tsc ) + { + plt_init(); + } + else + { + plt_overflow_period = scale_delta( + 1ull << (pts->counter_bits - 1), &plt_scale); + init_timer(&plt_overflow_timer, plt_overflow, NULL, 0); + plt_overflow(NULL); + + printk("Platform timer overflow period is %lu secs\n", + plt_overflow_period/SECONDS(1)); + } platform_timer_stamp = plt_stamp64; stime_platform_stamp = NOW();