| Message ID | 1368027714-14506-3-git-send-email-stefano.stabellini@eu.citrix.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
Hi Stefano, On 08/05/13 16:41, Stefano Stabellini wrote: > Introduce CONFIG_PARAVIRT and PARAVIRT_TIME_ACCOUNTING on ARM. > > The only paravirt interface supported is pv_time_ops.steal_clock, so no > runtime pvops patching needed. > > This allows us to make use of steal_account_process_tick for stolen > ticks accounting. > > Changes in v3: > - improve commit description and Kconfig help text; > - no need to initialize pv_time_ops; > - add PARAVIRT_TIME_ACCOUNTING. > > Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com> > CC: linux@arm.linux.org.uk > CC: will.deacon@arm.com > CC: nico@linaro.org > CC: marc.zyngier@arm.com > CC: cov@codeaurora.org > CC: arnd@arndb.de > CC: olof@lixom.net > --- > arch/arm/Kconfig | 20 ++++++++++++++++++++ > arch/arm/include/asm/paravirt.h | 19 +++++++++++++++++++ > arch/arm/kernel/Makefile | 1 + > arch/arm/kernel/paravirt.c | 25 +++++++++++++++++++++++++ > 4 files changed, 65 insertions(+), 0 deletions(-) > create mode 100644 arch/arm/include/asm/paravirt.h > create mode 100644 arch/arm/kernel/paravirt.c > > diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig > index 344e299..89ee2f1 100644 > --- a/arch/arm/Kconfig > +++ b/arch/arm/Kconfig > @@ -1887,12 +1887,32 @@ config XEN_DOM0 > def_bool y > depends on XEN > > +config PARAVIRT > + bool "Enable paravirtualization code" > + ---help--- > + This changes the kernel so it can modify itself when it is run > + under a hypervisor, potentially improving performance significantly > + over full virtualization. > + > +config PARAVIRT_TIME_ACCOUNTING > + bool "Paravirtual steal time accounting" > + select PARAVIRT Surely you meant "depends on" instead of "select" here? Otherwise I don't really see the point of PARAVIRT... > + default n > + ---help--- > + Select this option to enable fine granularity task steal time > + accounting. Time spent executing other tasks in parallel with > + the current vCPU is discounted from the vCPU power. To account for > + that, there can be a small performance impact. > + > + If in doubt, say N here. > + > config XEN > bool "Xen guest support on ARM (EXPERIMENTAL)" > depends on ARM && AEABI && OF > depends on CPU_V7 && !CPU_V6 > depends on !GENERIC_ATOMIC64 > select ARM_PSCI > + select PARAVIRT > help > Say Y if you want to run Linux in a Virtual Machine on Xen on ARM. >
On Wed, 8 May 2013, Marc Zyngier wrote: > Hi Stefano, > > On 08/05/13 16:41, Stefano Stabellini wrote: > > Introduce CONFIG_PARAVIRT and PARAVIRT_TIME_ACCOUNTING on ARM. > > > > The only paravirt interface supported is pv_time_ops.steal_clock, so no > > runtime pvops patching needed. > > > > This allows us to make use of steal_account_process_tick for stolen > > ticks accounting. > > > > Changes in v3: > > - improve commit description and Kconfig help text; > > - no need to initialize pv_time_ops; > > - add PARAVIRT_TIME_ACCOUNTING. > > > > Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com> > > CC: linux@arm.linux.org.uk > > CC: will.deacon@arm.com > > CC: nico@linaro.org > > CC: marc.zyngier@arm.com > > CC: cov@codeaurora.org > > CC: arnd@arndb.de > > CC: olof@lixom.net > > --- > > arch/arm/Kconfig | 20 ++++++++++++++++++++ > > arch/arm/include/asm/paravirt.h | 19 +++++++++++++++++++ > > arch/arm/kernel/Makefile | 1 + > > arch/arm/kernel/paravirt.c | 25 +++++++++++++++++++++++++ > > 4 files changed, 65 insertions(+), 0 deletions(-) > > create mode 100644 arch/arm/include/asm/paravirt.h > > create mode 100644 arch/arm/kernel/paravirt.c > > > > diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig > > index 344e299..89ee2f1 100644 > > --- a/arch/arm/Kconfig > > +++ b/arch/arm/Kconfig > > @@ -1887,12 +1887,32 @@ config XEN_DOM0 > > def_bool y > > depends on XEN > > > > +config PARAVIRT > > + bool "Enable paravirtualization code" > > + ---help--- > > + This changes the kernel so it can modify itself when it is run > > + under a hypervisor, potentially improving performance significantly > > + over full virtualization. > > + > > +config PARAVIRT_TIME_ACCOUNTING > > + bool "Paravirtual steal time accounting" > > + select PARAVIRT > > Surely you meant "depends on" instead of "select" here? Otherwise I > don't really see the point of PARAVIRT... I agree with you that "depends on" seems to be the right thing here, but on x86 is actually select. The original commit is 095c0aa83e52d6c3dd7168610746703921f570af.
diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig index 344e299..89ee2f1 100644 --- a/arch/arm/Kconfig +++ b/arch/arm/Kconfig @@ -1887,12 +1887,32 @@ config XEN_DOM0 def_bool y depends on XEN +config PARAVIRT + bool "Enable paravirtualization code" + ---help--- + This changes the kernel so it can modify itself when it is run + under a hypervisor, potentially improving performance significantly + over full virtualization. + +config PARAVIRT_TIME_ACCOUNTING + bool "Paravirtual steal time accounting" + select PARAVIRT + default n + ---help--- + Select this option to enable fine granularity task steal time + accounting. Time spent executing other tasks in parallel with + the current vCPU is discounted from the vCPU power. To account for + that, there can be a small performance impact. + + If in doubt, say N here. + config XEN bool "Xen guest support on ARM (EXPERIMENTAL)" depends on ARM && AEABI && OF depends on CPU_V7 && !CPU_V6 depends on !GENERIC_ATOMIC64 select ARM_PSCI + select PARAVIRT help Say Y if you want to run Linux in a Virtual Machine on Xen on ARM. diff --git a/arch/arm/include/asm/paravirt.h b/arch/arm/include/asm/paravirt.h new file mode 100644 index 0000000..3b95bc6 --- /dev/null +++ b/arch/arm/include/asm/paravirt.h @@ -0,0 +1,19 @@ +#ifndef _ASM_ARM_PARAVIRT_H +#define _ASM_ARM_PARAVIRT_H + +struct static_key; +extern struct static_key paravirt_steal_enabled; +extern struct static_key paravirt_steal_rq_enabled; + +struct pv_time_ops { + unsigned long long (*steal_clock)(int cpu); +}; +extern struct pv_time_ops pv_time_ops; + +static inline u64 paravirt_steal_clock(int cpu) +{ + return pv_time_ops.steal_clock(cpu); +} + + +#endif diff --git a/arch/arm/kernel/Makefile b/arch/arm/kernel/Makefile index 5f3338e..d911db6 100644 --- a/arch/arm/kernel/Makefile +++ b/arch/arm/kernel/Makefile @@ -76,6 +76,7 @@ obj-$(CONFIG_ARM_CPU_TOPOLOGY) += topology.o ifneq ($(CONFIG_ARCH_EBSA110),y) obj-y += io.o endif +obj-$(CONFIG_PARAVIRT) += paravirt.o head-y := head$(MMUEXT).o obj-$(CONFIG_DEBUG_LL) += debug.o diff --git a/arch/arm/kernel/paravirt.c b/arch/arm/kernel/paravirt.c new file mode 100644 index 0000000..53f371e --- /dev/null +++ b/arch/arm/kernel/paravirt.c @@ -0,0 +1,25 @@ +/* + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * Copyright (C) 2013 Citrix Systems + * + * Author: Stefano Stabellini <stefano.stabellini@eu.citrix.com> + */ + +#include <linux/export.h> +#include <linux/jump_label.h> +#include <linux/types.h> +#include <asm/paravirt.h> + +struct static_key paravirt_steal_enabled; +struct static_key paravirt_steal_rq_enabled; + +struct pv_time_ops pv_time_ops; +EXPORT_SYMBOL_GPL(pv_time_ops);
Introduce CONFIG_PARAVIRT and PARAVIRT_TIME_ACCOUNTING on ARM. The only paravirt interface supported is pv_time_ops.steal_clock, so no runtime pvops patching needed. This allows us to make use of steal_account_process_tick for stolen ticks accounting. Changes in v3: - improve commit description and Kconfig help text; - no need to initialize pv_time_ops; - add PARAVIRT_TIME_ACCOUNTING. Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com> CC: linux@arm.linux.org.uk CC: will.deacon@arm.com CC: nico@linaro.org CC: marc.zyngier@arm.com CC: cov@codeaurora.org CC: arnd@arndb.de CC: olof@lixom.net --- arch/arm/Kconfig | 20 ++++++++++++++++++++ arch/arm/include/asm/paravirt.h | 19 +++++++++++++++++++ arch/arm/kernel/Makefile | 1 + arch/arm/kernel/paravirt.c | 25 +++++++++++++++++++++++++ 4 files changed, 65 insertions(+), 0 deletions(-) create mode 100644 arch/arm/include/asm/paravirt.h create mode 100644 arch/arm/kernel/paravirt.c