[PATCH v3 08/11] powerpc/smp: Check for duplicate topologies and consolidate
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STALE2210d
From: Srikar Dronamraju <hidden>
Date: 2020-10-07 18:39:07
Also in:
lkml
Subsystem:
linux for powerpc (32-bit and 64-bit), the rest · Maintainers:
Madhavan Srinivasan, Linus Torvalds
Revision v3 (2 revisions archived).
Revisions (2)
- v2
- v3 current [diff against previous]
CACHE and COREGROUP domains are now part of default topology. However on systems that don't support CACHE or COREGROUP, these domains will eventually be degenerated. The degeneration happens per CPU. Do note the current fixup_topology() logic ensures that mask of a domain that is not supported on the current platform is set to the previous domain. Instead of waiting for the scheduler to degenerated try to consolidate based on their masks and sd_flags. This is done just before setting the scheduler topology. Signed-off-by: Srikar Dronamraju <redacted> 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> Cc: Qian Cai <redacted> --- arch/powerpc/kernel/smp.c | 26 ++++++++++++++++++++++++++ 1 file changed, 26 insertions(+)
diff --git a/arch/powerpc/kernel/smp.c b/arch/powerpc/kernel/smp.c
index aeb219a4bf7a..6f866e6b12f8 100644
--- a/arch/powerpc/kernel/smp.c
+++ b/arch/powerpc/kernel/smp.c@@ -1401,6 +1401,8 @@ int setup_profiling_timer(unsigned int multiplier) static void fixup_topology(void) { + int i; + #ifdef CONFIG_SCHED_SMT if (has_big_cores) { pr_info("Big cores detected but using small core scheduling\n");
@@ -1410,6 +1412,30 @@ static void fixup_topology(void) if (!has_coregroup_support()) powerpc_topology[mc_idx].mask = powerpc_topology[cache_idx].mask; + + /* + * Try to consolidate topology levels here instead of + * allowing scheduler to degenerate. + * - Dont consolidate if masks are different. + * - Dont consolidate if sd_flags exists and are different. + */ + for (i = 1; i <= die_idx; i++) { + if (powerpc_topology[i].mask != powerpc_topology[i - 1].mask) + continue; + + if (powerpc_topology[i].sd_flags && powerpc_topology[i - 1].sd_flags && + powerpc_topology[i].sd_flags != powerpc_topology[i - 1].sd_flags) + continue; + + if (!powerpc_topology[i - 1].sd_flags) + powerpc_topology[i - 1].sd_flags = powerpc_topology[i].sd_flags; + + powerpc_topology[i].mask = powerpc_topology[i + 1].mask; + powerpc_topology[i].sd_flags = powerpc_topology[i + 1].sd_flags; +#ifdef CONFIG_SCHED_DEBUG + powerpc_topology[i].name = powerpc_topology[i + 1].name; +#endif + } } void __init smp_cpus_done(unsigned int max_cpus)
--
2.17.1