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https://github.com/slackhq/nebula.git
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JackDoan
7fe4fab167
When tun.pin_threads is on and tun.cpu_affinity is unset, pick pin CPUs from the allowed set that do not service any up physical NIC's MSI vectors (read-only walk of /sys/class/net/*/device/msi_irqs and /proc/irq/*/effective_affinity_list). The old allowed[i] default pinned encrypt threads onto exactly the cores drivers affine their first RX queue IRQs to; a flow whose RSS queue fired there had NAPI fighting encrypt for the core (measured 8.4 vs 10.2 Gbps REV bimodality). Falls back to the old spread, with a log, when there aren't enough IRQ-free CPUs - e.g. drivers that allocate one queue per core until the admin narrows them (ethtool -L). Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
72 lines
2.4 KiB
Go
72 lines
2.4 KiB
Go
package nebula
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import (
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"testing"
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"github.com/slackhq/nebula/config"
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"github.com/slackhq/nebula/test"
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"github.com/slackhq/nebula/util"
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"github.com/stretchr/testify/assert"
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)
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func TestChooseIRQFreeCPUs(t *testing.T) {
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irq := map[int]bool{0: true, 1: true, 2: true, 3: true}
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// Plenty of IRQ-free CPUs: take the first `routines` of them in order.
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assert.Equal(t, []int{4, 5}, chooseIRQFreeCPUs([]int{0, 1, 2, 3, 4, 5, 6}, irq, 2))
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// Exactly enough.
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assert.Equal(t, []int{4, 5, 6}, chooseIRQFreeCPUs([]int{0, 1, 2, 3, 4, 5, 6}, irq, 3))
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// Not enough IRQ-free CPUs: nil, caller keeps the old default rather
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// than doubling readers up on shared cores.
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assert.Nil(t, chooseIRQFreeCPUs([]int{0, 1, 2, 3, 4}, irq, 2))
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// No IRQ info at all behaves like a plain prefix of allowed.
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assert.Equal(t, []int{0, 1}, chooseIRQFreeCPUs([]int{0, 1, 2}, map[int]bool{}, 2))
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// Non-contiguous allowed set (cgroup cpuset) with holes.
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assert.Equal(t, []int{9, 12}, chooseIRQFreeCPUs([]int{1, 3, 9, 12}, map[int]bool{1: true, 3: true}, 2))
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}
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func TestParseCpuAffinity(t *testing.T) {
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l := test.NewLogger()
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// newConfig returns a config.C with tun.cpu_affinity set to v. A nil v
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// leaves the key unset.
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newConfig := func(v any) *config.C {
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c := config.NewC(l)
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if v != nil {
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c.Settings["tun"] = map[string]any{"cpu_affinity": v}
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}
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return c
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}
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// unset -> nil (listenIn falls back to spreading across the allowed set)
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assert.Nil(t, parseCpuAffinity(newConfig(nil), l, 1))
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// Pick a CPU we're actually allowed to run on so a valid list survives
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// validation regardless of the host's affinity mask.
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allowed, _ := util.AllowedCPUs()
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validCPU := 0
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if len(allowed) > 0 {
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validCPU = allowed[0]
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}
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// valid list -> parsed through unchanged
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assert.Equal(t, []int{validCPU, validCPU}, parseCpuAffinity(newConfig([]any{validCPU, validCPU}), l, 2))
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// a negative entry is out of range on every platform -> disables the override
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assert.Nil(t, parseCpuAffinity(newConfig([]any{validCPU, -1}), l, 2))
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// a non-integer entry -> disables the override
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assert.Nil(t, parseCpuAffinity(newConfig([]any{validCPU, "not-a-cpu"}), l, 2))
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// a CPU id outside the allowed set -> disables the override. Only assertable
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// where we can enumerate the allowed set (e.g. linux); 1<<20 is far beyond
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// any representable CPU id so it can never be in the mask.
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if len(allowed) > 0 {
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assert.Nil(t, parseCpuAffinity(newConfig([]any{1 << 20}), l, 1))
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}
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}
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