Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752727AbcLFCdk (ORCPT ); Mon, 5 Dec 2016 21:33:40 -0500 Received: from mail-wm0-f68.google.com ([74.125.82.68]:35578 "EHLO mail-wm0-f68.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752254AbcLFCcu (ORCPT ); Mon, 5 Dec 2016 21:32:50 -0500 From: Frederic Weisbecker To: LKML Cc: Frederic Weisbecker , Tony Luck , Wanpeng Li , Peter Zijlstra , Michael Ellerman , Heiko Carstens , Benjamin Herrenschmidt , Thomas Gleixner , Paul Mackerras , Ingo Molnar , Fenghua Yu , Rik van Riel , Martin Schwidefsky , Stanislaw Gruszka Subject: [PATCH 08/10] ia64: Accumulate cputime and account only on tick/task switch Date: Tue, 6 Dec 2016 03:32:21 +0100 Message-Id: <1480991543-6557-9-git-send-email-fweisbec@gmail.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1480991543-6557-1-git-send-email-fweisbec@gmail.com> References: <1480991543-6557-1-git-send-email-fweisbec@gmail.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4712 Lines: 151 Currently CONFIG_VIRT_CPU_ACCOUNTING_NATIVE accounts the cputime on any context boundary: irq entry/exit, guest entry/exit, context switch, etc... Calling functions such as account_system_time(), account_user_time() and such can be costly, especially if they are called on many fastpath such as twice per IRQ. Those functions do more than just accounting to kcpustat and task cputime. Depending on the config, some subsystems can perform unpleasant multiplications and divisions, among other things. So lets accumulate the cputime instead and delay the accounting on ticks and context switches only. Cc: Benjamin Herrenschmidt Cc: Paul Mackerras Cc: Michael Ellerman Cc: Heiko Carstens Cc: Martin Schwidefsky Cc: Tony Luck Cc: Fenghua Yu Cc: Peter Zijlstra Cc: Rik van Riel Cc: Thomas Gleixner Cc: Ingo Molnar Cc: Stanislaw Gruszka Cc: Wanpeng Li Signed-off-by: Frederic Weisbecker --- arch/ia64/include/asm/thread_info.h | 6 ++++ arch/ia64/kernel/time.c | 60 ++++++++++++++++++++++++++++--------- 2 files changed, 52 insertions(+), 14 deletions(-) diff --git a/arch/ia64/include/asm/thread_info.h b/arch/ia64/include/asm/thread_info.h index c702642..8742d74 100644 --- a/arch/ia64/include/asm/thread_info.h +++ b/arch/ia64/include/asm/thread_info.h @@ -27,6 +27,12 @@ struct thread_info { mm_segment_t addr_limit; /* user-level address space limit */ int preempt_count; /* 0=premptable, <0=BUG; will also serve as bh-counter */ #ifdef CONFIG_VIRT_CPU_ACCOUNTING_NATIVE + __u64 utime; + __u64 stime; + __u64 gtime; + __u64 hardirq_time; + __u64 softirq_time; + __u64 idle_time; __u64 ac_stamp; __u64 ac_leave; __u64 ac_stime; diff --git a/arch/ia64/kernel/time.c b/arch/ia64/kernel/time.c index 88f0984..8de59ae 100644 --- a/arch/ia64/kernel/time.c +++ b/arch/ia64/kernel/time.c @@ -63,14 +63,39 @@ extern cputime_t cycle_to_cputime(u64 cyc); void vtime_account_user(struct task_struct *tsk) { - cputime_t delta_utime; struct thread_info *ti = task_thread_info(tsk); + cputime_t delta; - if (ti->ac_utime) { - delta_utime = cycle_to_cputime(ti->ac_utime); - account_user_time(tsk, delta_utime); - ti->ac_utime = 0; + if (ti->utime) + account_user_time(tsk, cycle_to_cputime(ti->utime)); + + if (ti->gtime) + account_guest_time(tsk, cycle_to_cputime(ti->gtime)); + + if (ti->idle_time) + account_idle_time(cycle_to_cputime(ti->idle_time)); + + if (ti->stime) { + delta = cycle_to_cputime(ti->stime); + account_system_index_time(tsk, delta, CPUTIME_SYSTEM); + } + + if (ti->hardirq_time) { + delta = cycle_to_cputime(ti->hardirq_time); + account_system_index_time(tsk, delta, CPUTIME_IRQ); + } + + if (ti->softirq_time) { + delta = cycle_to_cputime(ti->softirq_time); + account_system_index_time(tsk, delta, CPUTIME_SOFTIRQ); } + + ti->utime = 0; + ti->gtime = 0; + ti->idle_time = 0; + ti->stime = 0; + ti->hardirq_time = 0; + ti->softirq_time = 0; } /* @@ -91,18 +116,15 @@ void arch_vtime_task_switch(struct task_struct *prev) * Account time for a transition between system, hard irq or soft irq state. * Note that this function is called with interrupts enabled. */ -static cputime_t vtime_delta(struct task_struct *tsk) +static __u64 vtime_delta(struct task_struct *tsk) { struct thread_info *ti = task_thread_info(tsk); - cputime_t delta_stime; - __u64 now; + __u64 now, delta_stime; WARN_ON_ONCE(!irqs_disabled()); now = ia64_get_itc(); - - delta_stime = cycle_to_cputime(ti->ac_stime + (now - ti->ac_stamp)); - ti->ac_stime = 0; + delta_stime = now - ti->ac_stamp; ti->ac_stamp = now; return delta_stime; @@ -110,15 +132,25 @@ static cputime_t vtime_delta(struct task_struct *tsk) void vtime_account_system(struct task_struct *tsk) { - cputime_t delta = vtime_delta(tsk); + struct thread_info *ti = task_thread_info(tsk); + __u64 stime = vtime_delta(tsk); - account_system_time(tsk, 0, delta); + if ((tsk->flags & PF_VCPU) && !irq_count()) + ti->gtime += stime; + else if (hardirq_count()) + ti->hardirq_time += stime; + else if (in_serving_softirq()) + ti->softirq_time += stime; + else + ti->stime += stime; } EXPORT_SYMBOL_GPL(vtime_account_system); void vtime_account_idle(struct task_struct *tsk) { - account_idle_time(vtime_delta(tsk)); + struct thread_info *ti = task_thread_info(tsk); + + ti->idle_time += vtime_delta(tsk); } #endif /* CONFIG_VIRT_CPU_ACCOUNTING_NATIVE */ -- 2.7.4