Messages in this thread Patch in this message | | | Date | Fri, 18 Jul 2014 16:50:40 +0200 | From | Peter Zijlstra <> | Subject | Re: Scheduler regression from caffcdd8d27ba78730d5540396ce72ad022aff2c |
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On Fri, Jul 18, 2014 at 04:16:48PM +0200, Peter Zijlstra wrote: > On Fri, Jul 18, 2014 at 08:01:26AM -0500, Bruno Wolff III wrote: > > build_sched_domain: cpu: 0 level: SMT cpu_map: 0-3 tl->mask: 0,2 > > [ 0.254433] build_sched_domain: cpu: 0 level: MC cpu_map: 0-3 tl->mask: 0 > > [ 0.254516] build_sched_domain: cpu: 0 level: DIE cpu_map: 0-3 tl->mask: 0-3 > > [ 0.254600] build_sched_domain: cpu: 1 level: SMT cpu_map: 0-3 tl->mask: 1,3 > > [ 0.254683] build_sched_domain: cpu: 1 level: MC cpu_map: 0-3 tl->mask: 1 > > [ 0.254766] build_sched_domain: cpu: 1 level: DIE cpu_map: 0-3 tl->mask: 0-3 > > [ 0.254850] build_sched_domain: cpu: 2 level: SMT cpu_map: 0-3 tl->mask: 0,2 > > [ 0.254932] build_sched_domain: cpu: 2 level: MC cpu_map: 0-3 tl->mask: 2 > > [ 0.255005] build_sched_domain: cpu: 2 level: DIE cpu_map: 0-3 tl->mask: 0-3 > > [ 0.255091] build_sched_domain: cpu: 3 level: SMT cpu_map: 0-3 tl->mask: 1,3 > > [ 0.255176] build_sched_domain: cpu: 3 level: MC cpu_map: 0-3 tl->mask: 3 > > [ 0.255260] build_sched_domain: cpu: 3 level: DIE cpu_map: 0-3 tl->mask: 0-3 > > *blink*... > > That's, shall we say, unexpected. Let me ponder that a bit. HPA any clue > why a machine might report such a weird topology? AFAIK threads _always_ > share cache. So how can cpu_coregroup_mask be a subset (instead of a > superset) of topology_thread_cpumask? > > Let me go stare at the x86 topology mask setup code.
Possibly something like so, but I'm not too sure. Anybody?
--- arch/x86/kernel/smpboot.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-)
diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c index 5492798930ef..5eefa9abc2a9 100644 --- a/arch/x86/kernel/smpboot.c +++ b/arch/x86/kernel/smpboot.c @@ -338,9 +338,15 @@ static bool match_llc(struct cpuinfo_x86 *c, struct cpuinfo_x86 *o) { int cpu1 = c->cpu_index, cpu2 = o->cpu_index; - if (per_cpu(cpu_llc_id, cpu1) != BAD_APICID && - per_cpu(cpu_llc_id, cpu1) == per_cpu(cpu_llc_id, cpu2)) + if (cpu_has_topoext) { + if (per_cpu(cpu_llc_id, cpu1) != BAD_APICID && + per_cpu(cpu_llc_id, cpu1) == per_cpu(cpu_llc_id, cpu2)) + return topology_sane(c, o, "llc"); + + } else if (c->phys_proc_id == o->phys_proc_id && + c->cpu_core_id == o->cpu_core_id) { return topology_sane(c, o, "llc"); + } return false; }
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