Files
llmgw/internal/modelplan/mig_test.go
Ilker ManapandClaude Opus 5.5 0fd55a862b MIG: a card in MIG mode is placed as its instances, each a GPU of class <card>-mig-<profile>
Discovery reports a card in MIG mode as its instances instead of the whole
card, on both paths: nvidia-smi (-L names them, -q -x gives their memory,
ids and processes) and NVML (GetMigMode, GetMaxMigDeviceCount,
GetMigDeviceHandleByIndex, behind an interface so it is tested with a fake).
Each instance has its MIG UUID, its own memory, and a class from the card's
and the profile: a100-80g-mig-3g.40gb. Placement numbers instances
1000 + 100 x card + instance and every view shows them as card/migN.

A replica on MIG runs on exactly one instance: a process opens one MIG
device and instances have no NVLink between them, so tp, pp, gpus or nodes
above one on a MIG class are refused in catalog validation and again in
placement, and the planner offers one instance or none. The agent gives
the engine CUDA_VISIBLE_DEVICES=MIG-<uuid> (no Vulkan device variable on
MIG). Memory and processes are per instance; heat, power and wear the
card's; utilisation is left out rather than reported as zero. A card in MIG
mode with nothing carved stays out of placement with the reason, and
llmgw doctor reports each card's mode and instances and warns of the states
in which nothing can run. ctl nodes, ctl status, the console and the plan
count devices by class. docs/install.md has a MIG section.

Written against fakes of nvidia-smi and NVML output; not yet run on MIG
hardware.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
2026-10-05 00:01:14 +02:00

70 lines
2.4 KiB
Go
Raw Permalink Blame History

This file contains ambiguous Unicode characters
This file contains Unicode characters that might be confused with other characters. If you think that this is intentional, you can safely ignore this warning. Use the Escape button to reveal them.
package modelplan
import (
"strings"
"testing"
)
const mig3g = "a100-80g-mig-3g.40gb"
func TestAMIGInstanceIsSizedByItsProfileNotItsCard(t *testing.T) {
for class, want := range map[string]int{
mig3g: 40, "h100-80g-mig-1g.10gb": 10, "h100-80g-mig-1g.10gb-me": 10, "a100-80g": 80, "a100-80g-mig-": 0,
} {
if got := MemFromClass(class); got != want {
t.Errorf("MemFromClass(%q) = %d, want %d", class, got, want)
}
}
}
func TestAModelThatFitsOneMIGInstanceIsPlannedOnOne(t *testing.T) {
// Four instances free on each of two nodes on a fabric: a 3B fits one,
// and a 70B, which no single instance holds, is not spread over several
// — a replica cannot use more than one.
hw := []Hardware{{Class: mig3g, GPUMemGB: 40, GPUsPerNode: 4, Nodes: 2, Fabric: "ib-a"}}
fits := Fits(coder3B, hw, 32768, []Precision{BF16})
if len(fits) == 0 {
t.Fatal("a 3B does not fit a 40 GB MIG instance")
}
for _, f := range fits {
if f.TP != 1 || f.Nodes != 1 {
t.Errorf("planned across MIG instances: %s", f.Describe())
}
}
if fits := Fits(llama70B, hw, 8192, []Precision{BF16}); len(fits) != 0 {
t.Errorf("a 70B was planned on MIG instances: %s", fits[0].Describe())
}
}
func TestANodeWithACardInMIGModeOffersEachOfItsClasses(t *testing.T) {
// Card 0 cut into two 3g.40gb instances, card 1 whole: two classes on
// one node, each with its own count.
nodes := []PoolNode{{ID: "a100", Class: mig3g, GPUs: 3, FreeGPUs: 3, HostMemGB: 512, HostFreeGB: 400,
Kinds: []PoolKind{
{Class: mig3g, GPUMemGB: 40, GPUs: 2, FreeGPUs: 2},
{Class: "a100-80g", GPUMemGB: 80, GPUs: 1, FreeGPUs: 1},
}}}
arts := []Artifact{
{Name: "q4.gguf", Format: "gguf", Bytes: 9 * gib},
{Name: "f16.gguf", Format: "gguf", Bytes: 29 * gib},
{Name: "big.gguf", Format: "gguf", Bytes: 60 * gib},
}
opts := Options(arts, shape14B, nodes, 16384)
got := strings.Join(labels(opts), "; ")
for _, want := range []string{"q4.gguf 1 × " + mig3g, "f16.gguf 1 × " + mig3g, "big.gguf 1 × a100-80g"} {
if !strings.Contains(got, want) {
t.Errorf("missing %q in %s", want, got)
}
}
// Sixty gigabytes is more than an instance holds, and two instances are
// not one bigger device.
if strings.Contains(got, "big.gguf 2 × "+mig3g) {
t.Errorf("planned across two MIG instances: %s", got)
}
for _, o := range opts {
if o.Class == mig3g && (o.Hosts != 1 || !o.FreeNow) {
t.Errorf("the MIG option counts %d hosts, free %v", o.Hosts, o.FreeNow)
}
}
}