From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757534Ab0GATmZ (ORCPT ); Thu, 1 Jul 2010 15:42:25 -0400 Received: from mx1.redhat.com ([209.132.183.28]:14907 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756244Ab0GATmX (ORCPT ); Thu, 1 Jul 2010 15:42:23 -0400 Message-ID: <4C2CEF5D.8060609@redhat.com> Date: Thu, 01 Jul 2010 15:41:17 -0400 From: Don Dutile Reply-To: ddutile@redhat.com User-Agent: Thunderbird 2.0.0.18 (X11/20081113) MIME-Version: 1.0 To: stefano@stabellini.net CC: linux-kernel@vger.kernel.org, xen-devel@lists.xensource.com, Stefano.Stabellini@eu.citrix.com, sheng@linux.intel.com, jeremy@goop.org Subject: Re: [PATCH 11/13] Use xen_vcpuop_clockevent, xen_clocksource and xen wallclock. References: <1277136847-13266-11-git-send-email-stefano@stabellini.net> In-Reply-To: <1277136847-13266-11-git-send-email-stefano@stabellini.net> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org stefano@stabellini.net wrote: > From: Stefano Stabellini > > Use xen_vcpuop_clockevent instead of hpet and APIC timers as main > clockevent device on all vcpus, use the xen wallclock time as wallclock > instead of rtc and use xen_clocksource as clocksource. > The pv clock algorithm needs to work correctly for the xen_clocksource > and xen wallclock to be usable, only modern Xen versions offer a > reliable pv clock in HVM guests (XENFEAT_hvm_safe_pvclock). > > Using the hpet as clocksource means a VMEXIT every time we read/write to > the hpet mmio addresses, pvclock give us a better rating without > VMEXITs. Same goes for the xen wallclock and xen_vcpuop_clockevent > > Signed-off-by: Stefano Stabellini > --- > arch/x86/xen/enlighten.c | 14 +-------- > arch/x86/xen/suspend.c | 4 ++ > arch/x86/xen/time.c | 59 ++++++++++++++++++++++++++++++++++--- > arch/x86/xen/xen-ops.h | 7 +--- > include/xen/interface/features.h | 3 ++ > 5 files changed, 65 insertions(+), 22 deletions(-) > > diff --git a/arch/x86/xen/enlighten.c b/arch/x86/xen/enlighten.c > index 90bac21..bcd98a9 100644 > --- a/arch/x86/xen/enlighten.c > +++ b/arch/x86/xen/enlighten.c > @@ -933,10 +933,6 @@ static const struct pv_init_ops xen_init_ops __initdata = { > .patch = xen_patch, > }; > > -static const struct pv_time_ops xen_time_ops __initdata = { > - .sched_clock = xen_sched_clock, > -}; > - > static const struct pv_cpu_ops xen_cpu_ops __initdata = { > .cpuid = xen_cpuid, > > @@ -1074,7 +1070,6 @@ asmlinkage void __init xen_start_kernel(void) > /* Install Xen paravirt ops */ > pv_info = xen_info; > pv_init_ops = xen_init_ops; > - pv_time_ops = xen_time_ops; > pv_cpu_ops = xen_cpu_ops; > pv_apic_ops = xen_apic_ops; > > @@ -1082,13 +1077,7 @@ asmlinkage void __init xen_start_kernel(void) > x86_init.oem.arch_setup = xen_arch_setup; > x86_init.oem.banner = xen_banner; > > - x86_init.timers.timer_init = xen_time_init; > - x86_init.timers.setup_percpu_clockev = x86_init_noop; > - x86_cpuinit.setup_percpu_clockev = x86_init_noop; > - > - x86_platform.calibrate_tsc = xen_tsc_khz; > - x86_platform.get_wallclock = xen_get_wallclock; > - x86_platform.set_wallclock = xen_set_wallclock; > + xen_init_time_ops(); > > /* > * Set up some pagetable state before starting to set any ptes. > @@ -1330,4 +1319,5 @@ void __init xen_hvm_guest_init(void) > register_cpu_notifier(&xen_hvm_cpu_notifier); > have_vcpu_info_placement = 0; > x86_init.irqs.intr_init = xen_init_IRQ; > + xen_hvm_init_time_ops(); > } > diff --git a/arch/x86/xen/suspend.c b/arch/x86/xen/suspend.c > index 6ff9665..0774c67 100644 > --- a/arch/x86/xen/suspend.c > +++ b/arch/x86/xen/suspend.c > @@ -28,8 +28,12 @@ void xen_pre_suspend(void) > > void xen_hvm_post_suspend(int suspend_cancelled) > { > + int cpu; > xen_hvm_init_shared_info(); > xen_callback_vector(); > + for_each_online_cpu(cpu) { > + xen_setup_runstate_info(cpu); > + } > } > As I found out on older xen (non 'modern Xen version' ;-) ) w/o XENFEAT_hvm_safe_pvclock, the above patch should look like: if (xen_feature(XENFEAT_hvm_safe_pvclock)) { int cpu; for_each_online_cpu(cpu) { xen_setup_runstate_info(cpu); } } - Don > void xen_post_suspend(int suspend_cancelled) > diff --git a/arch/x86/xen/time.c b/arch/x86/xen/time.c > index 32764b8..2d76c28 100644 > --- a/arch/x86/xen/time.c > +++ b/arch/x86/xen/time.c > @@ -20,6 +20,7 @@ > #include > > #include > +#include > #include > #include > > @@ -160,7 +161,7 @@ static void do_stolen_accounting(void) > * nanoseconds, which is nanoseconds the VCPU spent in RUNNING+BLOCKED > * states. > */ > -unsigned long long xen_sched_clock(void) > +static unsigned long long xen_sched_clock(void) > { > struct vcpu_runstate_info state; > cycle_t now; > @@ -195,7 +196,7 @@ unsigned long long xen_sched_clock(void) > > > /* Get the TSC speed from Xen */ > -unsigned long xen_tsc_khz(void) > +static unsigned long xen_tsc_khz(void) > { > struct pvclock_vcpu_time_info *info = > &HYPERVISOR_shared_info->vcpu_info[0].time; > @@ -230,7 +231,7 @@ static void xen_read_wallclock(struct timespec *ts) > put_cpu_var(xen_vcpu); > } > > -unsigned long xen_get_wallclock(void) > +static unsigned long xen_get_wallclock(void) > { > struct timespec ts; > > @@ -238,7 +239,7 @@ unsigned long xen_get_wallclock(void) > return ts.tv_sec; > } > > -int xen_set_wallclock(unsigned long now) > +static int xen_set_wallclock(unsigned long now) > { > /* do nothing for domU */ > return -1; > @@ -473,7 +474,11 @@ void xen_timer_resume(void) > } > } > > -__init void xen_time_init(void) > +static const struct pv_time_ops xen_time_ops __initdata = { > + .sched_clock = xen_sched_clock, > +}; > + > +static __init void xen_time_init(void) > { > int cpu = smp_processor_id(); > > @@ -497,3 +502,47 @@ __init void xen_time_init(void) > xen_setup_timer(cpu); > xen_setup_cpu_clockevents(); > } > + > +__init void xen_init_time_ops(void) > +{ > + pv_time_ops = xen_time_ops; > + > + x86_init.timers.timer_init = xen_time_init; > + x86_init.timers.setup_percpu_clockev = x86_init_noop; > + x86_cpuinit.setup_percpu_clockev = x86_init_noop; > + > + x86_platform.calibrate_tsc = xen_tsc_khz; > + x86_platform.get_wallclock = xen_get_wallclock; > + x86_platform.set_wallclock = xen_set_wallclock; > +} > + > +static void xen_hvm_setup_cpu_clockevents(void) > +{ > + int cpu = smp_processor_id(); > + xen_setup_runstate_info(cpu); > + xen_setup_timer(cpu); > + xen_setup_cpu_clockevents(); > +} > + > +__init void xen_hvm_init_time_ops(void) > +{ > + /* vector callback is needed otherwise we cannot receive interrupts > + * on cpu > 0 */ > + if (!xen_have_vector_callback && num_present_cpus() > 1) > + return; > + if (!xen_feature(XENFEAT_hvm_safe_pvclock)) { > + printk(KERN_INFO "Xen doesn't support pvclock on HVM," > + "disable pv timer\n"); > + return; > + } > + > + pv_time_ops = xen_time_ops; > + x86_init.timers.timer_init = xen_time_init; > + x86_init.timers.setup_percpu_clockev = x86_init_noop; > + x86_cpuinit.setup_percpu_clockev = xen_hvm_setup_cpu_clockevents; > + > + x86_platform.calibrate_tsc = xen_tsc_khz; > + x86_platform.get_wallclock = xen_get_wallclock; > + x86_platform.set_wallclock = xen_set_wallclock; > +} > + > diff --git a/arch/x86/xen/xen-ops.h b/arch/x86/xen/xen-ops.h > index 01c9dd3..089d189 100644 > --- a/arch/x86/xen/xen-ops.h > +++ b/arch/x86/xen/xen-ops.h > @@ -49,11 +49,8 @@ void xen_setup_runstate_info(int cpu); > void xen_teardown_timer(int cpu); > cycle_t xen_clocksource_read(void); > void xen_setup_cpu_clockevents(void); > -unsigned long xen_tsc_khz(void); > -void __init xen_time_init(void); > -unsigned long xen_get_wallclock(void); > -int xen_set_wallclock(unsigned long time); > -unsigned long long xen_sched_clock(void); > +void __init xen_init_time_ops(void); > +void __init xen_hvm_init_time_ops(void); > > irqreturn_t xen_debug_interrupt(int irq, void *dev_id); > > diff --git a/include/xen/interface/features.h b/include/xen/interface/features.h > index 8ab08b9..70d2563 100644 > --- a/include/xen/interface/features.h > +++ b/include/xen/interface/features.h > @@ -44,6 +44,9 @@ > /* x86: Does this Xen host support the HVM callback vector type? */ > #define XENFEAT_hvm_callback_vector 8 > > +/* x86: pvclock algorithm is safe to use on HVM */ > +#define XENFEAT_hvm_safe_pvclock 9 > + > #define XENFEAT_NR_SUBMAPS 1 > > #endif /* __XEN_PUBLIC_FEATURES_H__ */