Re: [PATCH v2 04/10] powerpc/smp: Enable small core scheduling sooner

[Srikar Dronamraju]

* Gautham R Shenoy  [2020-07-22 11:29:25]:

> Hello Srikar,
> 
> On Tue, Jul 21, 2020 at 05:08:08PM +0530, Srikar Dronamraju wrote:
> > Enable small core scheduling as soon as we detect that we are in a
> > system that supports thread group. Doing so would avoid a redundant
> > check.
> 
> The patch looks good to me. However, I think the commit message still
> reflect the v1 code where we were moving the functionality from
> smp_cpus_done() to init_big_cores().
> 
> In this we are moving it to a helper function to collate all fixups to
> topology.
> 

Right.
Thanks for pointing , will correct this.


-- 
Thanks and Regards
Srikar Dronamraju

Re: [PATCH v2 04/10] powerpc/smp: Enable small core scheduling sooner

[Gautham R Shenoy]

Hello Srikar,

On Tue, Jul 21, 2020 at 05:08:08PM +0530, Srikar Dronamraju wrote:
> Enable small core scheduling as soon as we detect that we are in a
> system that supports thread group. Doing so would avoid a redundant
> check.

The patch looks good to me. However, I think the commit message still
reflect the v1 code where we were moving the functionality from
smp_cpus_done() to init_big_cores().

In this we are moving it to a helper function to collate all fixups to
topology.

> 
> Cc: linuxppc-dev 
> Cc: LKML 
> Cc: Michael Ellerman 
> Cc: Ingo Molnar 
> Cc: Peter Zijlstra 
> Cc: Valentin Schneider 
> Cc: Nick Piggin 
> Cc: Oliver OHalloran 
> Cc: Nathan Lynch 
> Cc: Michael Neuling 
> Cc: Anton Blanchard 
> Cc: Gautham R Shenoy 
> Cc: Vaidyanathan Srinivasan 
> Cc: Jordan Niethe 
> Signed-off-by: Srikar Dronamraju 
> ---
> Changelog v1 -> v2:
> powerpc/smp: Enable small core scheduling sooner
>   Restored the previous info msg (Jordan)
>   Moved big core topology fixup to fixup_topology (Gautham)
> 
>  arch/powerpc/kernel/smp.c | 17 +++--
>  1 file changed, 11 insertions(+), 6 deletions(-)
> 
> diff --git a/arch/powerpc/kernel/smp.c b/arch/powerpc/kernel/smp.c
> index 1ce95da00cb6..72f16dc0cb26 100644
> --- a/arch/powerpc/kernel/smp.c
> +++ b/arch/powerpc/kernel/smp.c
> @@ -1370,6 +1370,16 @@ int setup_profiling_timer(unsigned int multiplier)
>   return 0;
>  }
> 
> +static void fixup_topology(void)
> +{
> +#ifdef CONFIG_SCHED_SMT
> + if (has_big_cores) {
> + pr_info("Big cores detected but using small core scheduling\n");
> + powerpc_topology[0].mask = smallcore_smt_mask;
> + }
> +#endif
> +}
> +
>  void __init smp_cpus_done(unsigned int max_cpus)
>  {
>   /*
> @@ -1383,12 +1393,7 @@ void __init smp_cpus_done(unsigned int max_cpus)
> 
>   dump_numa_cpu_topology();
> 
> -#ifdef CONFIG_SCHED_SMT
> - if (has_big_cores) {
> - pr_info("Big cores detected but using small core scheduling\n");
> - powerpc_topology[0].mask = smallcore_smt_mask;
> - }
> -#endif
> + fixup_topology();
>   set_sched_topology(powerpc_topology);
>  }
> 
> -- 
> 2.17.1
> 

[PATCH v2 04/10] powerpc/smp: Enable small core scheduling sooner

[Srikar Dronamraju]

Enable small core scheduling as soon as we detect that we are in a
system that supports thread group. Doing so would avoid a redundant
check.

Cc: linuxppc-dev 
Cc: LKML 
Cc: Michael Ellerman 
Cc: Ingo Molnar 
Cc: Peter Zijlstra 
Cc: Valentin Schneider 
Cc: Nick Piggin 
Cc: Oliver OHalloran 
Cc: Nathan Lynch 
Cc: Michael Neuling 
Cc: Anton Blanchard 
Cc: Gautham R Shenoy 
Cc: Vaidyanathan Srinivasan 
Cc: Jordan Niethe 
Signed-off-by: Srikar Dronamraju 
---
Changelog v1 -> v2:
powerpc/smp: Enable small core scheduling sooner
Restored the previous info msg (Jordan)
Moved big core topology fixup to fixup_topology (Gautham)

 arch/powerpc/kernel/smp.c | 17 +++--
 1 file changed, 11 insertions(+), 6 deletions(-)

diff --git a/arch/powerpc/kernel/smp.c b/arch/powerpc/kernel/smp.c
index 1ce95da00cb6..72f16dc0cb26 100644
--- a/arch/powerpc/kernel/smp.c
+++ b/arch/powerpc/kernel/smp.c
@@ -1370,6 +1370,16 @@ int setup_profiling_timer(unsigned int multiplier)
return 0;
 }
 
+static void fixup_topology(void)
+{
+#ifdef CONFIG_SCHED_SMT
+   if (has_big_cores) {
+   pr_info("Big cores detected but using small core scheduling\n");
+   powerpc_topology[0].mask = smallcore_smt_mask;
+   }
+#endif
+}
+
 void __init smp_cpus_done(unsigned int max_cpus)
 {
/*
@@ -1383,12 +1393,7 @@ void __init smp_cpus_done(unsigned int max_cpus)
 
dump_numa_cpu_topology();
 
-#ifdef CONFIG_SCHED_SMT
-   if (has_big_cores) {
-   pr_info("Big cores detected but using small core scheduling\n");
-   powerpc_topology[0].mask = smallcore_smt_mask;
-   }
-#endif
+   fixup_topology();
set_sched_topology(powerpc_topology);
 }
 
-- 
2.17.1