From patchwork Thu Jul 11 14:24:02 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Luis Henriques X-Patchwork-Id: 258487 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from huckleberry.canonical.com (huckleberry.canonical.com [91.189.94.19]) by ozlabs.org (Postfix) with ESMTP id 50C692C0313 for ; Fri, 12 Jul 2013 00:26:43 +1000 (EST) Received: from localhost ([127.0.0.1] helo=huckleberry.canonical.com) by huckleberry.canonical.com with esmtp (Exim 4.76) (envelope-from ) id 1UxHpM-00084b-Kl; Thu, 11 Jul 2013 14:26:36 +0000 Received: from youngberry.canonical.com ([91.189.89.112]) by huckleberry.canonical.com with esmtp (Exim 4.76) (envelope-from ) id 1UxHoi-0007gC-Sk for kernel-team@lists.ubuntu.com; Thu, 11 Jul 2013 14:25:56 +0000 Received: from bl15-104-132.dsl.telepac.pt ([188.80.104.132] helo=localhost) by youngberry.canonical.com with esmtpsa (TLS1.0:DHE_RSA_AES_128_CBC_SHA1:16) (Exim 4.71) (envelope-from ) id 1UxHoi-0001br-Fg; Thu, 11 Jul 2013 14:25:56 +0000 From: Luis Henriques To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Subject: [PATCH 32/98] xen/time: remove blocked time accounting from xen "clockchip" Date: Thu, 11 Jul 2013 15:24:02 +0100 Message-Id: <1373552708-15235-33-git-send-email-luis.henriques@canonical.com> X-Mailer: git-send-email 1.8.1.2 In-Reply-To: <1373552708-15235-1-git-send-email-luis.henriques@canonical.com> References: <1373552708-15235-1-git-send-email-luis.henriques@canonical.com> X-Extended-Stable: 3.5 Cc: John Haxby , Laszlo Ersek , Konrad Rzeszutek Wilk X-BeenThere: kernel-team@lists.ubuntu.com X-Mailman-Version: 2.1.14 Precedence: list List-Id: Kernel team discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Errors-To: kernel-team-bounces@lists.ubuntu.com Sender: kernel-team-bounces@lists.ubuntu.com 3.5.7.17 -stable review patch. If anyone has any objections, please let me know. ------------------ From: Laszlo Ersek commit 0b0c002c340e78173789f8afaa508070d838cf3d upstream. ... because the "clock_event_device framework" already accounts for idle time through the "event_handler" function pointer in xen_timer_interrupt(). The patch is intended as the completion of [1]. It should fix the double idle times seen in PV guests' /proc/stat [2]. It should be orthogonal to stolen time accounting (the removed code seems to be isolated). The approach may be completely misguided. [1] https://lkml.org/lkml/2011/10/6/10 [2] http://lists.xensource.com/archives/html/xen-devel/2010-08/msg01068.html John took the time to retest this patch on top of v3.10 and reported: "idle time is correctly incremented for pv and hvm for the normal case, nohz=off and nohz=idle." so lets put this patch in. Signed-off-by: Laszlo Ersek Signed-off-by: John Haxby Signed-off-by: Konrad Rzeszutek Wilk Signed-off-by: Luis Henriques --- arch/x86/xen/time.c | 17 ++--------------- 1 file changed, 2 insertions(+), 15 deletions(-) diff --git a/arch/x86/xen/time.c b/arch/x86/xen/time.c index 054cc01..d50a821 100644 --- a/arch/x86/xen/time.c +++ b/arch/x86/xen/time.c @@ -36,9 +36,8 @@ static DEFINE_PER_CPU(struct vcpu_runstate_info, xen_runstate); /* snapshots of runstate info */ static DEFINE_PER_CPU(struct vcpu_runstate_info, xen_runstate_snapshot); -/* unused ns of stolen and blocked time */ +/* unused ns of stolen time */ static DEFINE_PER_CPU(u64, xen_residual_stolen); -static DEFINE_PER_CPU(u64, xen_residual_blocked); /* return an consistent snapshot of 64-bit time/counter value */ static u64 get64(const u64 *p) @@ -115,7 +114,7 @@ static void do_stolen_accounting(void) { struct vcpu_runstate_info state; struct vcpu_runstate_info *snap; - s64 blocked, runnable, offline, stolen; + s64 runnable, offline, stolen; cputime_t ticks; get_runstate_snapshot(&state); @@ -125,7 +124,6 @@ static void do_stolen_accounting(void) snap = &__get_cpu_var(xen_runstate_snapshot); /* work out how much time the VCPU has not been runn*ing* */ - blocked = state.time[RUNSTATE_blocked] - snap->time[RUNSTATE_blocked]; runnable = state.time[RUNSTATE_runnable] - snap->time[RUNSTATE_runnable]; offline = state.time[RUNSTATE_offline] - snap->time[RUNSTATE_offline]; @@ -141,17 +139,6 @@ static void do_stolen_accounting(void) ticks = iter_div_u64_rem(stolen, NS_PER_TICK, &stolen); __this_cpu_write(xen_residual_stolen, stolen); account_steal_ticks(ticks); - - /* Add the appropriate number of ticks of blocked time, - including any left-overs from last time. */ - blocked += __this_cpu_read(xen_residual_blocked); - - if (blocked < 0) - blocked = 0; - - ticks = iter_div_u64_rem(blocked, NS_PER_TICK, &blocked); - __this_cpu_write(xen_residual_blocked, blocked); - account_idle_ticks(ticks); } /* Get the TSC speed from Xen */