Re: [RFC PATCH 06/10] ARM: sched: Use device-tree to provide fast/slow CPU list for HMP
On Wed, 2012-10-10 at 12:04 +0100, Morten Rasmussen wrote:
> Hi Tixy,
>
> Could you have a look at my code stealing patch below? Since it is
> basically a trimmed version of one of your patches I would prefer to
> put you as author and have your SOB on it. What is your opinion?
Yes, I can agree with that opinion, (and my employer likes to count
their patch totals ;-) so please feel free to add:
From: Jon Medhurst
Signed-off-by: Jon Medhurst
Thanks
--
Tixy
> Thanks,
> Morten
>
> On Fri, Sep 21, 2012 at 07:32:21PM +0100, Morten Rasmussen wrote:
> > From: Morten Rasmussen
> >
> > We can't rely on Kconfig options to set the fast and slow CPU lists for
> > HMP scheduling if we want a single kernel binary to support multiple
> > devices with different CPU topology. E.g. TC2 (ARM's Test-Chip-2
> > big.LITTLE system), Fast Models, or even non big.LITTLE devices.
> >
> > This patch adds the function arch_get_fast_and_slow_cpus() to generate
> > the lists at run-time by parsing the CPU nodes in device-tree; it
> > assumes slow cores are A7s and everything else is fast. The function
> > still supports the old Kconfig options as this is useful for testing the
> > HMP scheduler on devices without big.LITTLE.
> >
> > This patch is reuse of a patch by Jon Medhurst with a
> > few bits left out.
> >
> > Signed-off-by: Morten Rasmussen
> > ---
> > arch/arm/Kconfig |4 ++-
> > arch/arm/kernel/topology.c | 69
> >
> > 2 files changed, 72 insertions(+), 1 deletion(-)
> >
> > diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
> > index cb80846..f1271bc 100644
> > --- a/arch/arm/Kconfig
> > +++ b/arch/arm/Kconfig
> > @@ -1588,13 +1588,15 @@ config HMP_FAST_CPU_MASK
> > string "HMP scheduler fast CPU mask"
> > depends on SCHED_HMP
> > help
> > - Specify the cpuids of the fast CPUs in the system as a list
> > string,
> > + Leave empty to use device tree information.
> > + Specify the cpuids of the fast CPUs in the system as a list string,
> > e.g. cpuid 0+1 should be specified as 0-1.
> >
> > config HMP_SLOW_CPU_MASK
> > string "HMP scheduler slow CPU mask"
> > depends on SCHED_HMP
> > help
> > + Leave empty to use device tree information.
> > Specify the cpuids of the slow CPUs in the system as a list string,
> > e.g. cpuid 0+1 should be specified as 0-1.
> >
> > diff --git a/arch/arm/kernel/topology.c b/arch/arm/kernel/topology.c
> > index 26c12c6..7682e12 100644
> > --- a/arch/arm/kernel/topology.c
> > +++ b/arch/arm/kernel/topology.c
> > @@ -317,6 +317,75 @@ void store_cpu_topology(unsigned int cpuid)
> > cpu_topology[cpuid].socket_id, mpidr);
> > }
> >
> > +
> > +#ifdef CONFIG_SCHED_HMP
> > +
> > +static const char * const little_cores[] = {
> > + "arm,cortex-a7",
> > + NULL,
> > +};
> > +
> > +static bool is_little_cpu(struct device_node *cn)
> > +{
> > + const char * const *lc;
> > + for (lc = little_cores; *lc; lc++)
> > + if (of_device_is_compatible(cn, *lc))
> > + return true;
> > + return false;
> > +}
> > +
> > +void __init arch_get_fast_and_slow_cpus(struct cpumask *fast,
> > + struct cpumask *slow)
> > +{
> > + struct device_node *cn = NULL;
> > + int cpu = 0;
> > +
> > + cpumask_clear(fast);
> > + cpumask_clear(slow);
> > +
> > + /*
> > +* Use the config options if they are given. This helps testing
> > +* HMP scheduling on systems without a big.LITTLE architecture.
> > +*/
> > + if (strlen(CONFIG_HMP_FAST_CPU_MASK) &&
> > strlen(CONFIG_HMP_SLOW_CPU_MASK)) {
> > + if (cpulist_parse(CONFIG_HMP_FAST_CPU_MASK, fast))
> > + WARN(1, "Failed to parse HMP fast cpu mask!\n");
> > + if (cpulist_parse(CONFIG_HMP_SLOW_CPU_MASK, slow))
> > + WARN(1, "Failed to parse HMP slow cpu mask!\n");
> > + return;
> > + }
> > +
> > + /*
> > +* Else, parse device tree for little cores.
> > +*/
> > + while ((cn = of_find_node_by_type(cn, "cpu"))) {
> > +
> > + if (cpu >= num_possible_cpus())
> > + break;
> > +
> > + if (is_little_cpu(cn))
> > + cpumask_set_cpu(cpu, slow);
> > + else
> > + cpumask_set_cpu(cpu, fast);
> > +
> > + cpu++;
> > + }
> > +
> > + if (!cpumask_empty(fast) && !cpumask_empty(slow))
> > + return;
> > +
> > + /*
> > +* We didn't find both big and little cores so let's call all cores
> > +* fast as this will keep the system running, with all cores being
> > +* treated equal.
> > +*/
> > + cpumask_setall(fast);
> > + cpumask_clear(slow);
> > +}
> > +
> > +#endif /* CONFIG_SCHED_HMP */
> > +
> > +
> > /*
> > * init_cpu_topology is called at boot when only one cpu is running
> > * which prevent simultaneous write access to cpu_topology array
> > --
>
Re: [RFC PATCH 06/10] ARM: sched: Use device-tree to provide fast/slow CPU list for HMP
Hi Tixy,
Could you have a look at my code stealing patch below? Since it is
basically a trimmed version of one of your patches I would prefer to
put you as author and have your SOB on it. What is your opinion?
Thanks,
Morten
On Fri, Sep 21, 2012 at 07:32:21PM +0100, Morten Rasmussen wrote:
> From: Morten Rasmussen
>
> We can't rely on Kconfig options to set the fast and slow CPU lists for
> HMP scheduling if we want a single kernel binary to support multiple
> devices with different CPU topology. E.g. TC2 (ARM's Test-Chip-2
> big.LITTLE system), Fast Models, or even non big.LITTLE devices.
>
> This patch adds the function arch_get_fast_and_slow_cpus() to generate
> the lists at run-time by parsing the CPU nodes in device-tree; it
> assumes slow cores are A7s and everything else is fast. The function
> still supports the old Kconfig options as this is useful for testing the
> HMP scheduler on devices without big.LITTLE.
>
> This patch is reuse of a patch by Jon Medhurst with a
> few bits left out.
>
> Signed-off-by: Morten Rasmussen
> ---
> arch/arm/Kconfig |4 ++-
> arch/arm/kernel/topology.c | 69
>
> 2 files changed, 72 insertions(+), 1 deletion(-)
>
> diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
> index cb80846..f1271bc 100644
> --- a/arch/arm/Kconfig
> +++ b/arch/arm/Kconfig
> @@ -1588,13 +1588,15 @@ config HMP_FAST_CPU_MASK
> string "HMP scheduler fast CPU mask"
> depends on SCHED_HMP
> help
> - Specify the cpuids of the fast CPUs in the system as a list string,
> + Leave empty to use device tree information.
> + Specify the cpuids of the fast CPUs in the system as a list string,
> e.g. cpuid 0+1 should be specified as 0-1.
>
> config HMP_SLOW_CPU_MASK
> string "HMP scheduler slow CPU mask"
> depends on SCHED_HMP
> help
> + Leave empty to use device tree information.
> Specify the cpuids of the slow CPUs in the system as a list string,
> e.g. cpuid 0+1 should be specified as 0-1.
>
> diff --git a/arch/arm/kernel/topology.c b/arch/arm/kernel/topology.c
> index 26c12c6..7682e12 100644
> --- a/arch/arm/kernel/topology.c
> +++ b/arch/arm/kernel/topology.c
> @@ -317,6 +317,75 @@ void store_cpu_topology(unsigned int cpuid)
> cpu_topology[cpuid].socket_id, mpidr);
> }
>
> +
> +#ifdef CONFIG_SCHED_HMP
> +
> +static const char * const little_cores[] = {
> + "arm,cortex-a7",
> + NULL,
> +};
> +
> +static bool is_little_cpu(struct device_node *cn)
> +{
> + const char * const *lc;
> + for (lc = little_cores; *lc; lc++)
> + if (of_device_is_compatible(cn, *lc))
> + return true;
> + return false;
> +}
> +
> +void __init arch_get_fast_and_slow_cpus(struct cpumask *fast,
> + struct cpumask *slow)
> +{
> + struct device_node *cn = NULL;
> + int cpu = 0;
> +
> + cpumask_clear(fast);
> + cpumask_clear(slow);
> +
> + /*
> + * Use the config options if they are given. This helps testing
> + * HMP scheduling on systems without a big.LITTLE architecture.
> + */
> + if (strlen(CONFIG_HMP_FAST_CPU_MASK) &&
> strlen(CONFIG_HMP_SLOW_CPU_MASK)) {
> + if (cpulist_parse(CONFIG_HMP_FAST_CPU_MASK, fast))
> + WARN(1, "Failed to parse HMP fast cpu mask!\n");
> + if (cpulist_parse(CONFIG_HMP_SLOW_CPU_MASK, slow))
> + WARN(1, "Failed to parse HMP slow cpu mask!\n");
> + return;
> + }
> +
> + /*
> + * Else, parse device tree for little cores.
> + */
> + while ((cn = of_find_node_by_type(cn, "cpu"))) {
> +
> + if (cpu >= num_possible_cpus())
> + break;
> +
> + if (is_little_cpu(cn))
> + cpumask_set_cpu(cpu, slow);
> + else
> + cpumask_set_cpu(cpu, fast);
> +
> + cpu++;
> + }
> +
> + if (!cpumask_empty(fast) && !cpumask_empty(slow))
> + return;
> +
> + /*
> + * We didn't find both big and little cores so let's call all cores
> + * fast as this will keep the system running, with all cores being
> + * treated equal.
> + */
> + cpumask_setall(fast);
> + cpumask_clear(slow);
> +}
> +
> +#endif /* CONFIG_SCHED_HMP */
> +
> +
> /*
> * init_cpu_topology is called at boot when only one cpu is running
> * which prevent simultaneous write access to cpu_topology array
> --
> 1.7.9.5
>
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Re: [RFC PATCH 06/10] ARM: sched: Use device-tree to provide fast/slow CPU list for HMP
On 10 October 2012 15:47, Morten Rasmussen wrote: > On Thu, Oct 04, 2012 at 07:49:32AM +0100, Viresh Kumar wrote: >> > This patch is reuse of a patch by Jon Medhurst with a >> > few bits left out. >> >> Then probably he must be the author of this commit? Also a SOB is required >> from him here. >> > > I don't know what the correct procedure is for this sort of partial > patch reuse. Since I didn't know better, I adopted Tixy's own reference > style that he used in one of his patches which is an extension of a > previous patch by me. I will of course fix it to follow normal procedure > if there is one. AFAIK, if you have used only some part of the earlier patch, then you just need to add an SOB of original author. But if you have picked most of the stuff from original patch, which i feel is the case here, you must have original author in author & SOB + your SOB. > It would be very easy to blame someone else here... :) I will fix it. :) -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [RFC PATCH 06/10] ARM: sched: Use device-tree to provide fast/slow CPU list for HMP
On Thu, Oct 04, 2012 at 07:49:32AM +0100, Viresh Kumar wrote:
> On 22 September 2012 00:02, wrote:
> > From: Morten Rasmussen
> >
> > We can't rely on Kconfig options to set the fast and slow CPU lists for
> > HMP scheduling if we want a single kernel binary to support multiple
> > devices with different CPU topology. E.g. TC2 (ARM's Test-Chip-2
> > big.LITTLE system), Fast Models, or even non big.LITTLE devices.
> >
> > This patch adds the function arch_get_fast_and_slow_cpus() to generate
> > the lists at run-time by parsing the CPU nodes in device-tree; it
> > assumes slow cores are A7s and everything else is fast. The function
> > still supports the old Kconfig options as this is useful for testing the
> > HMP scheduler on devices without big.LITTLE.
>
> But this code is handling this case too at the end, with following logic:
>
> > + cpumask_setall(fast);
> > + cpumask_clear(slow);
>
> Am i missing something?
>
The HMP setup can be defined using Kconfig or DT. If both fails, it will
set all cpus to be fast cpus and effectively disable SCHED_HMP. The
Kconfig option is kept to allow testing of alternative HMP setups
without having to change the DT or use DT at all which might be handy
for non-ARM platforms. I hope that answers you question.
> > This patch is reuse of a patch by Jon Medhurst with a
> > few bits left out.
>
> Then probably he must be the author of this commit? Also a SOB is required
> from him here.
>
I don't know what the correct procedure is for this sort of partial
patch reuse. Since I didn't know better, I adopted Tixy's own reference
style that he used in one of his patches which is an extension of a
previous patch by me. I will of course fix it to follow normal procedure
if there is one.
> > Signed-off-by: Morten Rasmussen
> > ---
> > arch/arm/Kconfig |4 ++-
> > arch/arm/kernel/topology.c | 69
> >
> > 2 files changed, 72 insertions(+), 1 deletion(-)
> >
> > diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
> > index cb80846..f1271bc 100644
> > --- a/arch/arm/Kconfig
> > +++ b/arch/arm/Kconfig
> > @@ -1588,13 +1588,15 @@ config HMP_FAST_CPU_MASK
> > string "HMP scheduler fast CPU mask"
> > depends on SCHED_HMP
> > help
> > - Specify the cpuids of the fast CPUs in the system as a list
> > string,
> > + Leave empty to use device tree information.
> > + Specify the cpuids of the fast CPUs in the system as a list
> > string,
> > e.g. cpuid 0+1 should be specified as 0-1.
> >
> > config HMP_SLOW_CPU_MASK
> > string "HMP scheduler slow CPU mask"
> > depends on SCHED_HMP
> > help
> > + Leave empty to use device tree information.
> > Specify the cpuids of the slow CPUs in the system as a list
> > string,
> > e.g. cpuid 0+1 should be specified as 0-1.
> >
> > diff --git a/arch/arm/kernel/topology.c b/arch/arm/kernel/topology.c
> > index 26c12c6..7682e12 100644
> > --- a/arch/arm/kernel/topology.c
> > +++ b/arch/arm/kernel/topology.c
> > @@ -317,6 +317,75 @@ void store_cpu_topology(unsigned int cpuid)
> > cpu_topology[cpuid].socket_id, mpidr);
> > }
> >
> > +
> > +#ifdef CONFIG_SCHED_HMP
> > +
> > +static const char * const little_cores[] = {
> > + "arm,cortex-a7",
> > + NULL,
> > +};
> > +
> > +static bool is_little_cpu(struct device_node *cn)
> > +{
> > + const char * const *lc;
> > + for (lc = little_cores; *lc; lc++)
> > + if (of_device_is_compatible(cn, *lc))
> > + return true;
> > + return false;
> > +}
> > +
> > +void __init arch_get_fast_and_slow_cpus(struct cpumask *fast,
> > + struct cpumask *slow)
> > +{
> > + struct device_node *cn = NULL;
> > + int cpu = 0;
> > +
> > + cpumask_clear(fast);
> > + cpumask_clear(slow);
> > +
> > + /*
> > +* Use the config options if they are given. This helps testing
> > +* HMP scheduling on systems without a big.LITTLE architecture.
> > +*/
> > + if (strlen(CONFIG_HMP_FAST_CPU_MASK) &&
> > strlen(CONFIG_HMP_SLOW_CPU_MASK)) {
> > + if (cpulist_parse(CONFIG_HMP_FAST_CPU_MASK, fast))
> > + WARN(1, "Failed to parse HMP fast cpu mask!\n");
> > + if (cpulist_parse(CONFIG_HMP_SLOW_CPU_MASK, slow))
> > + WARN(1, "Failed to parse HMP slow cpu mask!\n");
> > + return;
> > + }
> > +
> > + /*
> > +* Else, parse device tree for little cores.
> > +*/
> > + while ((cn = of_find_node_by_type(cn, "cpu"))) {
> > +
> > + if (cpu >= num_possible_cpus())
> > + break;
> > +
> > + if (is_little_cpu(cn))
> > + cpumask_set_cpu(cpu, slow);
> > + else
> > + cpumask_set_c
Re: [RFC PATCH 06/10] ARM: sched: Use device-tree to provide fast/slow CPU list for HMP
On 22 September 2012 00:02, wrote:
> From: Morten Rasmussen
>
> We can't rely on Kconfig options to set the fast and slow CPU lists for
> HMP scheduling if we want a single kernel binary to support multiple
> devices with different CPU topology. E.g. TC2 (ARM's Test-Chip-2
> big.LITTLE system), Fast Models, or even non big.LITTLE devices.
>
> This patch adds the function arch_get_fast_and_slow_cpus() to generate
> the lists at run-time by parsing the CPU nodes in device-tree; it
> assumes slow cores are A7s and everything else is fast. The function
> still supports the old Kconfig options as this is useful for testing the
> HMP scheduler on devices without big.LITTLE.
But this code is handling this case too at the end, with following logic:
> + cpumask_setall(fast);
> + cpumask_clear(slow);
Am i missing something?
> This patch is reuse of a patch by Jon Medhurst with a
> few bits left out.
Then probably he must be the author of this commit? Also a SOB is required
from him here.
> Signed-off-by: Morten Rasmussen
> ---
> arch/arm/Kconfig |4 ++-
> arch/arm/kernel/topology.c | 69
>
> 2 files changed, 72 insertions(+), 1 deletion(-)
>
> diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
> index cb80846..f1271bc 100644
> --- a/arch/arm/Kconfig
> +++ b/arch/arm/Kconfig
> @@ -1588,13 +1588,15 @@ config HMP_FAST_CPU_MASK
> string "HMP scheduler fast CPU mask"
> depends on SCHED_HMP
> help
> - Specify the cpuids of the fast CPUs in the system as a list string,
> + Leave empty to use device tree information.
> + Specify the cpuids of the fast CPUs in the system as a list string,
> e.g. cpuid 0+1 should be specified as 0-1.
>
> config HMP_SLOW_CPU_MASK
> string "HMP scheduler slow CPU mask"
> depends on SCHED_HMP
> help
> + Leave empty to use device tree information.
> Specify the cpuids of the slow CPUs in the system as a list string,
> e.g. cpuid 0+1 should be specified as 0-1.
>
> diff --git a/arch/arm/kernel/topology.c b/arch/arm/kernel/topology.c
> index 26c12c6..7682e12 100644
> --- a/arch/arm/kernel/topology.c
> +++ b/arch/arm/kernel/topology.c
> @@ -317,6 +317,75 @@ void store_cpu_topology(unsigned int cpuid)
> cpu_topology[cpuid].socket_id, mpidr);
> }
>
> +
> +#ifdef CONFIG_SCHED_HMP
> +
> +static const char * const little_cores[] = {
> + "arm,cortex-a7",
> + NULL,
> +};
> +
> +static bool is_little_cpu(struct device_node *cn)
> +{
> + const char * const *lc;
> + for (lc = little_cores; *lc; lc++)
> + if (of_device_is_compatible(cn, *lc))
> + return true;
> + return false;
> +}
> +
> +void __init arch_get_fast_and_slow_cpus(struct cpumask *fast,
> + struct cpumask *slow)
> +{
> + struct device_node *cn = NULL;
> + int cpu = 0;
> +
> + cpumask_clear(fast);
> + cpumask_clear(slow);
> +
> + /*
> +* Use the config options if they are given. This helps testing
> +* HMP scheduling on systems without a big.LITTLE architecture.
> +*/
> + if (strlen(CONFIG_HMP_FAST_CPU_MASK) &&
> strlen(CONFIG_HMP_SLOW_CPU_MASK)) {
> + if (cpulist_parse(CONFIG_HMP_FAST_CPU_MASK, fast))
> + WARN(1, "Failed to parse HMP fast cpu mask!\n");
> + if (cpulist_parse(CONFIG_HMP_SLOW_CPU_MASK, slow))
> + WARN(1, "Failed to parse HMP slow cpu mask!\n");
> + return;
> + }
> +
> + /*
> +* Else, parse device tree for little cores.
> +*/
> + while ((cn = of_find_node_by_type(cn, "cpu"))) {
> +
> + if (cpu >= num_possible_cpus())
> + break;
> +
> + if (is_little_cpu(cn))
> + cpumask_set_cpu(cpu, slow);
> + else
> + cpumask_set_cpu(cpu, fast);
> +
> + cpu++;
> + }
> +
> + if (!cpumask_empty(fast) && !cpumask_empty(slow))
> + return;
> +
> + /*
> +* We didn't find both big and little cores so let's call all cores
> +* fast as this will keep the system running, with all cores being
> +* treated equal.
> +*/
> + cpumask_setall(fast);
> + cpumask_clear(slow);
> +}
> +
> +#endif /* CONFIG_SCHED_HMP */
All above calls to of_*() routines have dependency on CONFIG_OF
--
viresh
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