[PATCH v2 11/11] powerpc/smp: Optimize update_coregroup_mask
From: Srikar Dronamraju <hidden>
Date: 2020-09-21 09:58:19
Also in:
lkml
Subsystem:
linux for powerpc (32-bit and 64-bit), the rest · Maintainers:
Madhavan Srinivasan, Michael Ellerman, Linus Torvalds
All threads of a SMT4/SMT8 core can either be part of CPU's coregroup mask or outside the coregroup. Use this relation to reduce the number of iterations needed to find all the CPUs that share the same coregroup Use a temporary mask to iterate through the CPUs that may share coregroup mask. Also instead of setting one CPU at a time into cpu_coregroup_mask, copy the SMT4/SMT8/submask at one shot. Cc: linuxppc-dev <redacted> Cc: LKML <redacted> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Anton Blanchard <redacted> Cc: Oliver O'Halloran <oohall@gmail.com> Cc: Nathan Lynch <redacted> Cc: Michael Neuling <redacted> Cc: Gautham R Shenoy <redacted> Cc: Satheesh Rajendran <redacted> Cc: Ingo Molnar <mingo@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Valentin Schneider <redacted> Signed-off-by: Srikar Dronamraju <redacted> --- arch/powerpc/kernel/smp.c | 30 ++++++++++++++++++++++-------- 1 file changed, 22 insertions(+), 8 deletions(-)
diff --git a/arch/powerpc/kernel/smp.c b/arch/powerpc/kernel/smp.c
index b48ae4e306d3..bbaea93dc558 100644
--- a/arch/powerpc/kernel/smp.c
+++ b/arch/powerpc/kernel/smp.c@@ -1339,19 +1339,33 @@ static inline void add_cpu_to_smallcore_masks(int cpu) static void update_coregroup_mask(int cpu) { - int first_thread = cpu_first_thread_sibling(cpu); + struct cpumask *(*submask_fn)(int) = cpu_sibling_mask; + cpumask_var_t mask; int coregroup_id = cpu_to_coregroup_id(cpu); int i; - cpumask_set_cpu(cpu, cpu_coregroup_mask(cpu)); - for_each_cpu_and(i, cpu_online_mask, cpu_cpu_mask(cpu)) { - int fcpu = cpu_first_thread_sibling(i); + alloc_cpumask_var_node(&mask, GFP_KERNEL, cpu_to_node(cpu)); + cpumask_and(mask, cpu_online_mask, cpu_cpu_mask(cpu)); + + if (shared_caches) + submask_fn = cpu_l2_cache_mask; + + /* Update coregroup mask with all the CPUs that are part of submask */ + or_cpumasks_related(cpu, cpu, submask_fn, cpu_coregroup_mask); + + /* Skip all CPUs already part of coregroup mask */ + cpumask_andnot(mask, mask, cpu_coregroup_mask(cpu)); - if (fcpu == first_thread) - set_cpus_related(cpu, i, cpu_coregroup_mask); - else if (coregroup_id == cpu_to_coregroup_id(i)) - set_cpus_related(cpu, i, cpu_coregroup_mask); + for_each_cpu(i, mask) { + /* Skip all CPUs not part of this coregroup */ + if (coregroup_id == cpu_to_coregroup_id(i)) { + or_cpumasks_related(cpu, i, submask_fn, cpu_coregroup_mask); + cpumask_andnot(mask, mask, submask_fn(i)); + } else { + cpumask_andnot(mask, mask, cpu_coregroup_mask(i)); + } } + free_cpumask_var(mask); } static void add_cpu_to_masks(int cpu)
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2.17.1