summaryrefslogtreecommitdiffstats
path: root/kernel/sched/topology.c (follow)
Commit message (Collapse)AuthorAgeFilesLines
* sched/topology: Rename sched_group_cpus()Peter Zijlstra2017-05-151-19/+19
| | | | | | | | | | | | | | | | | | | | | | | | | There's a discrepancy in naming between the sched_domain and sched_group cpumask accessor. Since we're doing changes, fix it. $ git grep sched_group_cpus | wc -l 28 $ git grep sched_domain_span | wc -l 38 Suggests changing sched_group_cpus() into sched_group_span(): for i in `git grep -l sched_group_cpus` do sed -ie 's/sched_group_cpus/sched_group_span/g' $i done Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
* sched/topology: Rename sched_group_mask()Peter Zijlstra2017-05-151-18/+15
| | | | | | | | | | | | | | Since sched_group_mask() is now an independent cpumask (it no longer masks sched_group_cpus()), rename the thing. Suggested-by: Lauro Ramos Venancio <lvenanci@redhat.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
* sched/topology: Simplify sched_group_mask() usagePeter Zijlstra2017-05-151-2/+3
| | | | | | | | | | | | | | | | | While writing the comments, it occurred to me that: sg_cpus & sg_mask == sg_mask at least conceptually; the !overlap case sets the all 1s mask. If we correct that we can simplify things and directly use sg_mask. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
* sched/topology: Rewrite get_group()Peter Zijlstra2017-05-151-24/+22
| | | | | | | | | | | | | | | | | | | | We want to attain: sg_cpus() & sg_mask() == sg_mask() for this to be so we must initialize sg_mask() to sg_cpus() for the !overlap case (its currently cpumask_setall()). Since the code makes my head hurt bad, rewrite it into a simpler form, inspired by the now fixed overlap code. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
* sched/topology: Add a few commentsPeter Zijlstra2017-05-151-7/+193
| | | | | | | | | | | | Try and describe what this code is about.. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
* sched/topology: Fix overlapping sched_group_capacityPeter Zijlstra2017-05-151-6/+16
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When building the overlapping groups we need to attach a consistent sched_group_capacity structure. That is, all 'identical' sched_group's should have the _same_ sched_group_capacity. This can (once again) be demonstrated with a topology like: node 0 1 2 3 0: 10 20 30 20 1: 20 10 20 30 2: 30 20 10 20 3: 20 30 20 10 But we need at least 2 CPUs per node for this to show up, after all, if there is only one CPU per node, our CPU @i is per definition a unique CPU that reaches this domain (aka balance-cpu). Given the above NUMA topo and 2 CPUs per node: [] CPU0 attaching sched-domain(s): [] domain-0: span=0,4 level=DIE [] groups: 0:{ span=0 }, 4:{ span=4 } [] domain-1: span=0-1,3-5,7 level=NUMA [] groups: 0:{ span=0,4 mask=0,4 cap=2048 }, 1:{ span=1,5 mask=1,5 cap=2048 }, 3:{ span=3,7 mask=3,7 cap=2048 } [] domain-2: span=0-7 level=NUMA [] groups: 0:{ span=0-1,3-5,7 mask=0,4 cap=6144 }, 2:{ span=1-3,5-7 mask=2,6 cap=6144 } [] CPU1 attaching sched-domain(s): [] domain-0: span=1,5 level=DIE [] groups: 1:{ span=1 }, 5:{ span=5 } [] domain-1: span=0-2,4-6 level=NUMA [] groups: 1:{ span=1,5 mask=1,5 cap=2048 }, 2:{ span=2,6 mask=2,6 cap=2048 }, 4:{ span=0,4 mask=0,4 cap=2048 } [] domain-2: span=0-7 level=NUMA [] groups: 1:{ span=0-2,4-6 mask=1,5 cap=6144 }, 3:{ span=0,2-4,6-7 mask=3,7 cap=6144 } Observe how CPU0-domain1-group0 and CPU1-domain1-group4 are the 'same' but have a different id (0 vs 4). To fix this, use the group balance CPU to select the SGC. This means we have to compute the full mask for each CPU and require a second temporary mask to store the group mask in (it otherwise lives in the SGC). The fixed topology looks like: [] CPU0 attaching sched-domain(s): [] domain-0: span=0,4 level=DIE [] groups: 0:{ span=0 }, 4:{ span=4 } [] domain-1: span=0-1,3-5,7 level=NUMA [] groups: 0:{ span=0,4 mask=0,4 cap=2048 }, 1:{ span=1,5 mask=1,5 cap=2048 }, 3:{ span=3,7 mask=3,7 cap=2048 } [] domain-2: span=0-7 level=NUMA [] groups: 0:{ span=0-1,3-5,7 mask=0,4 cap=6144 }, 2:{ span=1-3,5-7 mask=2,6 cap=6144 } [] CPU1 attaching sched-domain(s): [] domain-0: span=1,5 level=DIE [] groups: 1:{ span=1 }, 5:{ span=5 } [] domain-1: span=0-2,4-6 level=NUMA [] groups: 1:{ span=1,5 mask=1,5 cap=2048 }, 2:{ span=2,6 mask=2,6 cap=2048 }, 0:{ span=0,4 mask=0,4 cap=2048 } [] domain-2: span=0-7 level=NUMA [] groups: 1:{ span=0-2,4-6 mask=1,5 cap=6144 }, 3:{ span=0,2-4,6-7 mask=3,7 cap=6144 } Debugged-by: Lauro Ramos Venancio <lvenanci@redhat.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kernel@vger.kernel.org Fixes: e3589f6c81e4 ("sched: Allow for overlapping sched_domain spans") Signed-off-by: Ingo Molnar <mingo@kernel.org>
* sched/topology: Add sched_group_capacity debuggingPeter Zijlstra2017-05-151-10/+15
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Add sgc::id to easier spot domain construction issues. Take the opportunity to slightly rework the group printing, because adding more "(id: %d)" strings makes the entire thing very hard to read. Also the individual groups are very hard to separate, so add explicit visual grouping, which allows replacing all the "(%s: %d)" format things with shorter "%s=%d" variants. Then fix up some inconsistencies in surrounding prints for domains. The end result looks like: [] CPU0 attaching sched-domain(s): [] domain-0: span=0,4 level=DIE [] groups: 0:{ span=0 }, 4:{ span=4 } [] domain-1: span=0-1,3-5,7 level=NUMA [] groups: 0:{ span=0,4 mask=0,4 cap=2048 }, 1:{ span=1,5 mask=1,5 cap=2048 }, 3:{ span=3,7 mask=3,7 cap=2048 } [] domain-2: span=0-7 level=NUMA [] groups: 0:{ span=0-1,3-5,7 mask=0,4 cap=6144 }, 2:{ span=1-3,5-7 mask=2,6 cap=6144 } Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
* sched/topology: Small cleanupPeter Zijlstra2017-05-151-2/+5
| | | | | | | | | | | | | Move the allocation of topology specific cpumasks into the topology code. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
* sched/topology: Fix overlapping sched_group_maskPeter Zijlstra2017-05-151-1/+17
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The point of sched_group_mask is to select those CPUs from sched_group_cpus that can actually arrive at this balance domain. The current code gets it wrong, as can be readily demonstrated with a topology like: node 0 1 2 3 0: 10 20 30 20 1: 20 10 20 30 2: 30 20 10 20 3: 20 30 20 10 Where (for example) domain 1 on CPU1 ends up with a mask that includes CPU0: [] CPU1 attaching sched-domain: [] domain 0: span 0-2 level NUMA [] groups: 1 (mask: 1), 2, 0 [] domain 1: span 0-3 level NUMA [] groups: 0-2 (mask: 0-2) (cpu_capacity: 3072), 0,2-3 (cpu_capacity: 3072) This causes sched_balance_cpu() to compute the wrong CPU and consequently should_we_balance() will terminate early resulting in missed load-balance opportunities. The fixed topology looks like: [] CPU1 attaching sched-domain: [] domain 0: span 0-2 level NUMA [] groups: 1 (mask: 1), 2, 0 [] domain 1: span 0-3 level NUMA [] groups: 0-2 (mask: 1) (cpu_capacity: 3072), 0,2-3 (cpu_capacity: 3072) (note: this relies on OVERLAP domains to always have children, this is true because the regular topology domains are still here -- this is before degenerate trimming) Debugged-by: Lauro Ramos Venancio <lvenanci@redhat.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kernel@vger.kernel.org Cc: stable@vger.kernel.org Fixes: e3589f6c81e4 ("sched: Allow for overlapping sched_domain spans") Signed-off-by: Ingo Molnar <mingo@kernel.org>
* sched/topology: Remove FORCE_SD_OVERLAPPeter Zijlstra2017-05-151-1/+1
| | | | | | | | | | | | | | | | | Its an obsolete debug mechanism and future code wants to rely on properties this undermines. Namely, it would be good to assume that SD_OVERLAP domains have children, but if we build the entire hierarchy with SD_OVERLAP this is obviously false. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
* sched/topology: Move comment about asymmetric node setupsLauro Ramos Venancio2017-05-151-9/+10
| | | | | | | | | | | | | Signed-off-by: Lauro Ramos Venancio <lvenanci@redhat.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: lwang@redhat.com Cc: riel@redhat.com Link: http://lkml.kernel.org/r/1492717903-5195-4-git-send-email-lvenanci@redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
* sched/topology: Optimize build_group_mask()Lauro Ramos Venancio2017-05-151-2/+2
| | | | | | | | | | | | | | | | | The group mask is always used in intersection with the group CPUs. So, when building the group mask, we don't have to care about CPUs that are not part of the group. Signed-off-by: Lauro Ramos Venancio <lvenanci@redhat.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: lwang@redhat.com Cc: riel@redhat.com Link: http://lkml.kernel.org/r/1492717903-5195-2-git-send-email-lvenanci@redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
* sched/topology: Verify the first group matches the child domainPeter Zijlstra2017-05-151-0/+6
| | | | | | | | | | | | | | | | | We want sched_groups to be sibling child domains (or individual CPUs when there are no child domains). Furthermore, since the first group of a domain should include the CPU of that domain, the first group of each domain should match the child domain. Verify this is indeed so. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
* sched/debug: Print the scheduler topology group maskPeter Zijlstra2017-05-151-1/+11
| | | | | | | | | | | | | In order to determine the balance_cpu (for should_we_balance()) we need the sched_group_mask() for overlapping domains. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
* sched/topology: Simplify build_overlap_sched_groups()Peter Zijlstra2017-05-151-11/+2
| | | | | | | | | | | | | | | | Now that the first group will always be the previous domain of this @cpu this can be simplified. In fact, writing the code now removed should've been a big clue I was doing it wrong :/ Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
* sched/topology: Fix building of overlapping sched-groupsPeter Zijlstra2017-05-151-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When building the overlapping groups, we very obviously should start with the previous domain of _this_ @cpu, not CPU-0. This can be readily demonstrated with a topology like: node 0 1 2 3 0: 10 20 30 20 1: 20 10 20 30 2: 30 20 10 20 3: 20 30 20 10 Where (for example) CPU1 ends up generating the following nonsensical groups: [] CPU1 attaching sched-domain: [] domain 0: span 0-2 level NUMA [] groups: 1 2 0 [] domain 1: span 0-3 level NUMA [] groups: 1-3 (cpu_capacity = 3072) 0-1,3 (cpu_capacity = 3072) Where the fact that domain 1 doesn't include a group with span 0-2 is the obvious fail. With patch this looks like: [] CPU1 attaching sched-domain: [] domain 0: span 0-2 level NUMA [] groups: 1 0 2 [] domain 1: span 0-3 level NUMA [] groups: 0-2 (cpu_capacity = 3072) 0,2-3 (cpu_capacity = 3072) Debugged-by: Lauro Ramos Venancio <lvenanci@redhat.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kernel@vger.kernel.org Cc: stable@vger.kernel.org Fixes: e3589f6c81e4 ("sched: Allow for overlapping sched_domain spans") Signed-off-by: Ingo Molnar <mingo@kernel.org>
* sched/topology: Refactor function build_overlap_sched_groups()Lauro Ramos Venancio2017-05-151-19/+43
| | | | | | | | | | | | | | | Create functions build_group_from_child_sched_domain() and init_overlap_sched_group(). No functional change. Signed-off-by: Lauro Ramos Venancio <lvenanci@redhat.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Rik van Riel <riel@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1492091769-19879-2-git-send-email-lvenanci@redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
* sched/topology: Split out scheduler topology code from core.c into topology.cIngo Molnar2017-02-071-0/+1658
Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>