win32: auto-enable the GPU in bare coli chat

On Windows a bare 'coli chat' (no --gpu/--vram/--auto-tier) ALWAYS ran
CPU-only, even on a CUDA build with a GPU present. Two defects:

1. cuda_binary() returned False on Windows. It detects CUDA by running
   'ldd glm | grep libcudart', which is Linux-only (no ldd on win32) and
   meaningless anyway because the Windows engine links cudart only inside a
   runtime-loaded coli_cuda.dll, not as a libcudart symbol in glm.exe. So
   the --gpu/--vram/--auto-tier gates (which call cuda_binary()) never opened.

2. Even with detection fixed, bare 'coli chat' set no CUDA env: env_for's
   else-branch only enables CUDA when --gpu/--vram is passed. Nothing
   auto-enabled the GPU.

Now: cuda_binary() on non-Linux returns True iff coli_cuda.dll exists next
to glm.exe — the exact file backend_loader.c loads from the engine's own
directory, so its presence is a faithful, cheap, DLL-hijack-safe proxy for a
CUDA-capable build. And env_for, scoped to win32 (Linux keeps its working
explicit-flag UX), auto-enables CUDA when a bare chat detects a CUDA build
plus a GPU via nvidia-smi, sizing the expert-tier VRAM budget from real free
VRAM via the existing build_plan/environment_for_plan machinery (same as
--auto-tier, no guessed budget). If nvidia-smi is missing it falls back to
CPU with a clear warning; --gpu none still forces CPU; explicit --vram/--gpu
still win. CUDA_DENSE stays an explicit opt-in (matches --auto-tier).

Verified on a Windows + RTX 5070 Ti box: bare 'coli chat --model <g64>' now
prints '[GPU] auto-enabled CUDA ... 13.0 GB expert tier' and emits
COLI_CUDA=1 / COLI_GPUS=0 / CUDA_EXPERT_GB=13.044 (was: all unset, CPU-only).

Tests: 4 new cases (auto-enable, nvidia-smi-missing fallback, CPU-build
silent, Linux-unchanged) plus the 4 existing default-I/O tests guarded to
mock cuda_binary() so they stay host-independent. Full python suite green
(env_defaults 8, resource_plan 10, doctor 8, makefile_platform 3, cli_output 3).

Out of scope: doctor.cuda_linkage is also POSIX-only and mis-reports on
Windows — separate follow-up.
This commit is contained in:
woolcoxm
2026-07-17 12:03:43 -04:00
parent e9b36141a4
commit 0b05f6a76b
3 changed files with 130 additions and 2 deletions
+37
View File
@@ -237,6 +237,43 @@ def env_for(a):
gpu=f" · VRAM {format_bytes(vt['budget_bytes'])}" if has_cuda and vt["devices"] else " · CPU"
print(f" {C.dim}[PLAN] RAM {format_bytes(rt['budget_bytes'])} · cap {rt['cache_slots_per_layer']}/layer{gpu}{C.r}",file=sys.stderr)
else:
# Windows: a bare `coli chat` (no --gpu/--vram/--auto-tier) used to ALWAYS
# run CPU-only, even on a CUDA build with a GPU present — cuda_binary()
# returned False on Windows (see above), and nothing set COLI_CUDA without
# an explicit flag. Now that detection works, auto-enable the GPU when one
# is detected so `coli chat` Just Works. Scoped to Windows: Linux already
# has working detection + the explicit-flag UX, and changing bare-chat
# semantics there is out of scope. Falls back to CPU with a warning if
# nvidia-smi is missing (discover_gpus can't size VRAM without it).
if (sys.platform == "win32" and a.gpu is None and not a.vram):
if cuda_binary():
from resource_plan import discover_gpus, build_plan, environment_for_plan, format_bytes
gpus = discover_gpus()
if gpus:
e["COLI_CUDA"]="1"
e.setdefault("COLI_GPUS", ",".join(str(g["index"]) for g in gpus))
# Reuse the planner so the expert-tier VRAM budget is the real
# free VRAM minus the 2 GB reserve — not a guess. Same machinery
# as --auto-tier, just without requiring the user to pass it.
ram,ctx,devices,vram_req = resource_request(a, e)
try:
plan=build_plan(a.model,ram,ctx,devices,vram_req,policy=a.policy)
e.update(environment_for_plan(plan,e,cuda_enabled=True))
vt=plan["tiers"]["vram"]
names=",".join(g["name"].strip() for g in gpus)
print(f" {C.dim}[GPU] auto-enabled CUDA · {names} · "
f"{format_bytes(vt['budget_bytes'])} expert tier{C.r}", file=sys.stderr)
except (OSError,ValueError,json.JSONDecodeError) as error:
# Plan failed (e.g. model dir unreadable): don't block the
# run, just leave the unsized COLI_CUDA=1 and let the engine
# pick its own budget. Engine handles a missing budget.
print(f" {C.yel}[GPU] auto-enable: could not size VRAM ({error}); "
f"using engine default{C.r}", file=sys.stderr)
else:
print(f" {C.yel}[GPU] coli_cuda.dll present but nvidia-smi not found on PATH "
f"(cannot size VRAM); running CPU-only. Add nvidia-smi to PATH or pass "
f"--vram N to enable CUDA.{C.r}", file=sys.stderr)
# else: CPU build (no coli_cuda.dll) — stay silent, CPU is correct.
# --gpu/--vram SENZA --auto-tier: prima venivano ignorati in silenzio e il run
# partiva CPU-only senza alcun avviso — benchmark "GPU" pubblicati per errore (#121).
if a.gpu is not None:
+84 -2
View File
@@ -32,9 +32,16 @@ def args(**over):
class EnvDefaultsTest(unittest.TestCase):
def env_for_with(self, environ, platform):
def env_for_with(self, environ, platform, cuda=False):
"""Run env_for on a bare-chat args() under a faked env + platform.
cuda=False by default so the existing default-I/O tests stay
deterministic: the Windows auto-enable branch calls cuda_binary() and
(if True) discover_gpus(), both of which reach the real machine — faking
False keeps these tests independent of the host's GPU."""
with mock.patch.dict(os.environ, environ, clear=True), \
mock.patch.object(sys, "platform", platform):
mock.patch.object(sys, "platform", platform), \
mock.patch.object(coli, "cuda_binary", return_value=cuda):
return coli.env_for(args())
def test_win32_sets_measured_defaults(self):
@@ -64,5 +71,80 @@ class EnvDefaultsTest(unittest.TestCase):
self.assertNotIn(k, e)
class CudaAutoEnableTest(unittest.TestCase):
"""Windows bare `coli chat` (no --gpu/--vram/--auto-tier) used to ALWAYS run
CPU-only even on a CUDA build with a GPU present. env_for now auto-enables
CUDA on win32 when cuda_binary() is True and a GPU is discoverable; falls
back to CPU with a warning if nvidia-smi (discover_gpus) is missing; stays
silent on a CPU build; and never touches the Linux path."""
def _env_for(self, platform, cuda, gpus, plan=None):
# Patch discover_gpus / build_plan / environment_for_plan at the
# resource_plan module (env_for imports them lazily on each call, so the
# patches are live when those imports run). Stubbing the planner keeps
# the test independent of a real model dir (args().model == "X").
import resource_plan
a = args()
GPB = 1024 ** 3
if plan is None:
plan = {"tiers": {"ram": {"budget_bytes": 16 * GPB, "cache_slots_per_layer": 4},
"vram": {"budget_bytes": int(8.0 * GPB), "devices": gpus}}}
def fake_environment_for_plan(p, env, cuda_enabled=True):
# Mirror the real contract: size CUDA_EXPERT_GB from the plan's VRAM
# budget (this is the value env_for propagates into the engine env).
r = dict(env)
if cuda_enabled and p["tiers"]["vram"]["devices"] and p["tiers"]["vram"]["budget_bytes"] > 0:
r["CUDA_EXPERT_GB"] = f"{p['tiers']['vram']['budget_bytes'] / GPB:.3f}"
return r
with mock.patch.dict(os.environ, {}, clear=True), \
mock.patch.object(sys, "platform", platform), \
mock.patch.object(coli, "cuda_binary", return_value=cuda), \
mock.patch.object(resource_plan, "discover_gpus", return_value=gpus), \
mock.patch.object(resource_plan, "build_plan", return_value=plan), \
mock.patch.object(resource_plan, "environment_for_plan",
side_effect=fake_environment_for_plan):
return coli.env_for(a)
def _fake_gpu(self, index=0, name="NVIDIA GeForce RTX 5070 Ti",
total_mib=16384, free_mib=15000):
return {"index": index, "name": name,
"total_bytes": total_mib * 1024 * 1024,
"free_bytes": free_mib * 1024 * 1024}
def test_win32_auto_enables_cuda_when_gpu_present(self):
e = self._env_for("win32", cuda=True, gpus=[self._fake_gpu()])
self.assertEqual(e["COLI_CUDA"], "1")
self.assertEqual(e["COLI_GPUS"], "0")
# VRAM budget is sized from free VRAM by build_plan (real minus reserve),
# so it must be present and positive — never a guess or zero.
self.assertIn("CUDA_EXPERT_GB", e)
self.assertGreater(float(e["CUDA_EXPERT_GB"]), 0.0)
# Dense offload is an explicit opt-in (matches --auto-tier): not set here.
self.assertNotIn("CUDA_DENSE", e)
def test_win32_falls_back_to_cpu_when_nvidia_smi_missing(self):
# coli_cuda.dll present (cuda=True) but nvidia-smi absent (no GPUs found)
# -> warn + CPU-only, never crash, never set COLI_CUDA.
e = self._env_for("win32", cuda=True, gpus=[])
self.assertNotIn("COLI_CUDA", e)
self.assertNotIn("COLI_GPUS", e)
self.assertNotIn("CUDA_EXPERT_GB", e)
def test_win32_cpu_build_stays_silent(self):
# No coli_cuda.dll (cuda=False) -> CPU build, nothing GPU-related emitted.
e = self._env_for("win32", cuda=False, gpus=[self._fake_gpu()])
self.assertNotIn("COLI_CUDA", e)
self.assertNotIn("COLI_GPUS", e)
def test_linux_bare_chat_not_auto_enabled(self):
# The auto-enable is scoped to win32: a Linux bare chat with a GPU
# present must NOT turn CUDA on (Linux keeps the explicit-flag UX).
e = self._env_for("linux", cuda=True, gpus=[self._fake_gpu()])
self.assertNotIn("COLI_CUDA", e)
self.assertNotIn("CUDA_EXPERT_GB", e)
if __name__ == "__main__":
unittest.main()
+9
View File
@@ -105,6 +105,15 @@ Format: `VAR` — default — effect.
| `COLI_CUDA_SHARED_W4A16_MIN_ROWS` | `32` | Min row count to engage the shared-MLP W4A16 kernel. |
| `COLI_METAL_UNTRACKED` | off (Metal only) | `=1` sets `MTLResourceHazardTrackingModeUntracked` on Metal buffers (reduces hazard-tracking overhead). |
> **Windows note.** On Windows, a bare `coli chat` / `coli run` / `coli serve`
> (no `--gpu`/`--vram`/`--auto-tier`) **auto-enables the GPU** when it detects a
> CUDA build (`coli_cuda.dll` next to the engine) and at least one GPU via
> `nvidia-smi`. The expert-tier VRAM budget is then sized automatically from the
> card's free VRAM (same computation as `--auto-tier`). If `nvidia-smi` is not on
> `PATH` the run falls back to CPU with a warning — pass `--vram N` (or add
> `nvidia-smi` to `PATH`) to enable CUDA in that case. `--gpu none` forces
> CPU-only. (Linux/macOS behaviour is unchanged: pass a flag to enable CUDA.)
---
## Advanced / experimental / debug