On Thu, 5 Nov 2015, 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.
>
> Signed-off-by: Stefano Stabellini <[email protected]>
> Acked-by: Christopher Covington <[email protected]>
> Acked-by: Ian Campbell <[email protected]>
> CC: [email protected]
> CC: [email protected]
> CC: [email protected]
> CC: [email protected]
> CC: [email protected]
> CC: [email protected]
> CC: [email protected]
Russell,
are you OK with this patch?
>
> Changes in v10:
> - replace "---help---" with "help"
>
> Changes in v7:
> - ifdef CONFIG_PARAVIRT the content of paravirt.h.
>
> Changes in v3:
> - improve commit description and Kconfig help text;
> - no need to initialize pv_time_ops;
> - add PARAVIRT_TIME_ACCOUNTING.
> ---
> arch/arm/Kconfig | 20 ++++++++++++++++++++
> arch/arm/include/asm/paravirt.h | 20 ++++++++++++++++++++
> arch/arm/kernel/Makefile | 1 +
> arch/arm/kernel/paravirt.c | 25 +++++++++++++++++++++++++
> 4 files changed, 66 insertions(+)
> 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 f1ed110..60be104 100644
> --- a/arch/arm/Kconfig
> +++ b/arch/arm/Kconfig
> @@ -1823,6 +1823,25 @@ config SWIOTLB
> config IOMMU_HELPER
> def_bool SWIOTLB
>
> +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_DOM0
> def_bool y
> depends on XEN
> @@ -1836,6 +1855,7 @@ config XEN
> select ARCH_DMA_ADDR_T_64BIT
> select ARM_PSCI
> select SWIOTLB_XEN
> + 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..8435ff59
> --- /dev/null
> +++ b/arch/arm/include/asm/paravirt.h
> @@ -0,0 +1,20 @@
> +#ifndef _ASM_ARM_PARAVIRT_H
> +#define _ASM_ARM_PARAVIRT_H
> +
> +#ifdef CONFIG_PARAVIRT
> +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
> +
> +#endif
> diff --git a/arch/arm/kernel/Makefile b/arch/arm/kernel/Makefile
> index af9e59b..3e6e937 100644
> --- a/arch/arm/kernel/Makefile
> +++ b/arch/arm/kernel/Makefile
> @@ -81,6 +81,7 @@ obj-$(CONFIG_VDSO) += vdso.o
> ifneq ($(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 <[email protected]>
> + */
> +
> +#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);
> --
> 1.7.10.4
>
On Tue, 10 Nov 2015, Stefano Stabellini wrote:
> On Thu, 5 Nov 2015, 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.
> >
> > Signed-off-by: Stefano Stabellini <[email protected]>
> > Acked-by: Christopher Covington <[email protected]>
> > Acked-by: Ian Campbell <[email protected]>
> > CC: [email protected]
> > CC: [email protected]
> > CC: [email protected]
> > CC: [email protected]
> > CC: [email protected]
> > CC: [email protected]
> > CC: [email protected]
>
>
> Russell,
> are you OK with this patch?
Russell,
I am going to drop this patch and add a small #ifdef to
arch/arm/xen/enlighten.c to be able to use this functionality on arm64.
If you change your mind let me know.
>
>
> >
> > Changes in v10:
> > - replace "---help---" with "help"
> >
> > Changes in v7:
> > - ifdef CONFIG_PARAVIRT the content of paravirt.h.
> >
> > Changes in v3:
> > - improve commit description and Kconfig help text;
> > - no need to initialize pv_time_ops;
> > - add PARAVIRT_TIME_ACCOUNTING.
> > ---
> > arch/arm/Kconfig | 20 ++++++++++++++++++++
> > arch/arm/include/asm/paravirt.h | 20 ++++++++++++++++++++
> > arch/arm/kernel/Makefile | 1 +
> > arch/arm/kernel/paravirt.c | 25 +++++++++++++++++++++++++
> > 4 files changed, 66 insertions(+)
> > 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 f1ed110..60be104 100644
> > --- a/arch/arm/Kconfig
> > +++ b/arch/arm/Kconfig
> > @@ -1823,6 +1823,25 @@ config SWIOTLB
> > config IOMMU_HELPER
> > def_bool SWIOTLB
> >
> > +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_DOM0
> > def_bool y
> > depends on XEN
> > @@ -1836,6 +1855,7 @@ config XEN
> > select ARCH_DMA_ADDR_T_64BIT
> > select ARM_PSCI
> > select SWIOTLB_XEN
> > + 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..8435ff59
> > --- /dev/null
> > +++ b/arch/arm/include/asm/paravirt.h
> > @@ -0,0 +1,20 @@
> > +#ifndef _ASM_ARM_PARAVIRT_H
> > +#define _ASM_ARM_PARAVIRT_H
> > +
> > +#ifdef CONFIG_PARAVIRT
> > +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
> > +
> > +#endif
> > diff --git a/arch/arm/kernel/Makefile b/arch/arm/kernel/Makefile
> > index af9e59b..3e6e937 100644
> > --- a/arch/arm/kernel/Makefile
> > +++ b/arch/arm/kernel/Makefile
> > @@ -81,6 +81,7 @@ obj-$(CONFIG_VDSO) += vdso.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 <[email protected]>
> > + */
> > +
> > +#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);
> > --
> > 1.7.10.4
> >
> --
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> Please read the FAQ at http://www.tux.org/lkml/
>
Hi Stefano,
On 11/20/2015 09:31 AM, Stefano Stabellini wrote:
> On Tue, 10 Nov 2015, Stefano Stabellini wrote:
>> On Thu, 5 Nov 2015, 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.
>>>
>>> Signed-off-by: Stefano Stabellini <[email protected]>
>>> Acked-by: Christopher Covington <[email protected]>
>>> Acked-by: Ian Campbell <[email protected]>
>>> CC: [email protected]
>>> CC: [email protected]
>>> CC: [email protected]
>>> CC: [email protected]
>>> CC: [email protected]
>>> CC: [email protected]
>>> CC: [email protected]
>>
>>
>> Russell,
>> are you OK with this patch?
>
> Russell,
>
> I am going to drop this patch and add a small #ifdef to
> arch/arm/xen/enlighten.c to be able to use this functionality on arm64.
>
> If you change your mind let me know.
It appears to me as though he's not copied on this message.
Regards,
Christopher Covington
--
Qualcomm Innovation Center, Inc.
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project
On Fri, 20 Nov 2015, Christopher Covington wrote:
> Hi Stefano,
>
> On 11/20/2015 09:31 AM, Stefano Stabellini wrote:
> > On Tue, 10 Nov 2015, Stefano Stabellini wrote:
> >> On Thu, 5 Nov 2015, 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.
> >>>
> >>> Signed-off-by: Stefano Stabellini <[email protected]>
> >>> Acked-by: Christopher Covington <[email protected]>
> >>> Acked-by: Ian Campbell <[email protected]>
> >>> CC: [email protected]
> >>> CC: [email protected]
> >>> CC: [email protected]
> >>> CC: [email protected]
> >>> CC: [email protected]
> >>> CC: [email protected]
> >>> CC: [email protected]
> >>
> >>
> >> Russell,
> >> are you OK with this patch?
> >
> > Russell,
> >
> > I am going to drop this patch and add a small #ifdef to
> > arch/arm/xen/enlighten.c to be able to use this functionality on arm64.
> >
> > If you change your mind let me know.
>
> It appears to me as though he's not copied on this message.
He was. He is now in To:.
On Fri, Nov 20, 2015 at 02:40:31PM +0000, Stefano Stabellini wrote:
> On Fri, 20 Nov 2015, Christopher Covington wrote:
> > Hi Stefano,
> >
> > On 11/20/2015 09:31 AM, Stefano Stabellini wrote:
> > > On Tue, 10 Nov 2015, Stefano Stabellini wrote:
> > >> On Thu, 5 Nov 2015, 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.
> > >>>
> > >>> Signed-off-by: Stefano Stabellini <[email protected]>
> > >>> Acked-by: Christopher Covington <[email protected]>
> > >>> Acked-by: Ian Campbell <[email protected]>
> > >>> CC: [email protected]
> > >>> CC: [email protected]
> > >>> CC: [email protected]
> > >>> CC: [email protected]
> > >>> CC: [email protected]
> > >>> CC: [email protected]
> > >>> CC: [email protected]
> > >>
> > >>
> > >> Russell,
> > >> are you OK with this patch?
> > >
> > > Russell,
> > >
> > > I am going to drop this patch and add a small #ifdef to
> > > arch/arm/xen/enlighten.c to be able to use this functionality on arm64.
> > >
> > > If you change your mind let me know.
> >
> > It appears to me as though he's not copied on this message.
>
> He was. He is now in To:.
I think the patch is fine.
Sorry, but I no longer read every email that passes by due to the amount
of email I now receive, and due to the nature of modern email clients with
their stupid ideas about how to formulate the To: and Cc: headers for
replies[*], I attach no significance to being mentioned in either the To:
or Cc: headers.
Overall, what this means is it's now difficult to attact my attention to
any particular thread. Sorry about that, I have no solution to this
problem.
* - modern mailers have started to preserve the To: and Cc: headers from
the message being replied to, which means that if I'm mentioned in the
To: header initially, my address stays in the To: header despite the
discussion not being directed _at_ me. Hence, deciding what to reply to
based on where my address appears in the headers is meaningless with
modern mail clients.
--
FTTC broadband for 0.8mile line: currently at 9.6Mbps down 400kbps up
according to speedtest.net.
On Fri, 20 Nov 2015, Russell King - ARM Linux wrote:
> On Fri, Nov 20, 2015 at 02:40:31PM +0000, Stefano Stabellini wrote:
> > On Fri, 20 Nov 2015, Christopher Covington wrote:
> > > Hi Stefano,
> > >
> > > On 11/20/2015 09:31 AM, Stefano Stabellini wrote:
> > > > On Tue, 10 Nov 2015, Stefano Stabellini wrote:
> > > >> On Thu, 5 Nov 2015, 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.
> > > >>>
> > > >>> Signed-off-by: Stefano Stabellini <[email protected]>
> > > >>> Acked-by: Christopher Covington <[email protected]>
> > > >>> Acked-by: Ian Campbell <[email protected]>
> > > >>> CC: [email protected]
> > > >>> CC: [email protected]
> > > >>> CC: [email protected]
> > > >>> CC: [email protected]
> > > >>> CC: [email protected]
> > > >>> CC: [email protected]
> > > >>> CC: [email protected]
> > > >>
> > > >>
> > > >> Russell,
> > > >> are you OK with this patch?
> > > >
> > > > Russell,
> > > >
> > > > I am going to drop this patch and add a small #ifdef to
> > > > arch/arm/xen/enlighten.c to be able to use this functionality on arm64.
> > > >
> > > > If you change your mind let me know.
> > >
> > > It appears to me as though he's not copied on this message.
> >
> > He was. He is now in To:.
>
> I think the patch is fine.
Thanks
> Sorry, but I no longer read every email that passes by due to the amount
> of email I now receive, and due to the nature of modern email clients with
> their stupid ideas about how to formulate the To: and Cc: headers for
> replies[*], I attach no significance to being mentioned in either the To:
> or Cc: headers.
>
> Overall, what this means is it's now difficult to attact my attention to
> any particular thread. Sorry about that, I have no solution to this
> problem.
FWIW as somebody that receives pretty large amounts of emails myself
with my name in CC or To, I understand and I don't have a solution
either :-(
> * - modern mailers have started to preserve the To: and Cc: headers from
> the message being replied to, which means that if I'm mentioned in the
> To: header initially, my address stays in the To: header despite the
> discussion not being directed _at_ me. Hence, deciding what to reply to
> based on where my address appears in the headers is meaningless with
> modern mail clients.
>
> --
> FTTC broadband for 0.8mile line: currently at 9.6Mbps down 400kbps up
> according to speedtest.net.
>