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 <[email protected]>
>
> 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 <[email protected]> with a
> few bits left out.
>
> Signed-off-by: Morten Rasmussen <[email protected]>
> ---
> 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
>
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 <[email protected]>
Signed-off-by: Jon Medhurst <[email protected]>
Thanks
--
Tixy
> Thanks,
> Morten
>
> On Fri, Sep 21, 2012 at 07:32:21PM +0100, Morten Rasmussen wrote:
> > From: Morten Rasmussen <[email protected]>
> >
> > 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 <[email protected]> with a
> > few bits left out.
> >
> > Signed-off-by: Morten Rasmussen <[email protected]>
> > ---
> > 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
> >
>