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import math
import os
import select
import signal
import statistics
import struct
import subprocess
import sys
import time
import numpy as np
sys.path.insert(0, os.path.dirname(os.path.abspath(__file__)))
import graph_spec
_HDR = struct.Struct("<4sQ")
N_WORKERS = 8
N_CPUS = 8
WARMUPS = 3
REPS = 15
BUILD_TIMEOUT_SEC = 20.0
CALL_TIMEOUT_SEC = 120.0
ABS_TOL = 1e-3
REL_TOL = 1e-3
AGENT_UID = 1001
class WorkerError(RuntimeError):
"""Any failure of a child: crash, protocol violation, timeout, bad output."""
def _uid_of(pid):
try:
with open("/proc/%d/status" % pid, "rb") as fh:
for line in fh:
if line.startswith(b"Uid:"):
return int(line.split()[1])
except (OSError, IndexError, ValueError):
pass
return None
def _tasks_stopped(pids):
for pid in pids:
try:
tids = os.listdir("/proc/%d/task" % pid)
except OSError:
continue
for tid in tids:
try:
with open("/proc/%d/task/%s/stat" % (pid, tid), "rb") as fh:
state = fh.read().rsplit(b")", 1)[1].split()[0]
except (OSError, IndexError):
continue
if state not in (b"T", b"Z", b"X"):
return False
return True
class Child:
"""A worker subprocess, SIGSTOPped whenever it is not the one being timed."""
def __init__(self, kind, rundir, python, launch_prefix=(), env=None,
popen_kwargs=None):
self.kind = kind
argv = list(launch_prefix) + [python, "-I", "-B",
os.path.join(rundir, "worker.py"), kind]
self.proc = subprocess.Popen(
argv, stdin=subprocess.PIPE, stdout=subprocess.PIPE,
stderr=subprocess.PIPE, cwd=rundir, env=env, close_fds=True,
start_new_session=True, **(popen_kwargs or {}))
self.rfd = self.proc.stdout.fileno()
self.wfd = self.proc.stdin.fileno()
self.stopped = False
self._pids = None
self._expect(b"HI", BUILD_TIMEOUT_SEC)
def _send(self, cmd, payload=b""):
buf = _HDR.pack(cmd.ljust(4, b"\0"), len(payload)) + payload
off = 0
deadline = time.monotonic() + CALL_TIMEOUT_SEC
while off < len(buf):
if time.monotonic() > deadline:
raise WorkerError("%s: timed out sending a request" % self.kind)
_, w, _ = select.select([], [self.wfd], [], 1.0)
if not w:
continue
try:
off += os.write(self.wfd, buf[off:off + (1 << 20)])
except OSError as exc:
raise WorkerError("%s: pipe closed while sending (%s)" % (self.kind, exc))
def _read_exactly(self, n, deadline):
out = bytearray()
while len(out) < n:
remaining = deadline - time.monotonic()
if remaining <= 0:
raise WorkerError("%s: timed out waiting for a response" % self.kind)
r, _, _ = select.select([self.rfd], [], [], min(1.0, remaining))
if not r:
continue
chunk = os.read(self.rfd, n - len(out))
if not chunk:
raise WorkerError("%s: exited before responding (rc=%s)"
% (self.kind, self.proc.poll()))
out += chunk
return bytes(out)
def _expect(self, cmd, timeout):
deadline = time.monotonic() + timeout
got, ln = _HDR.unpack(self._read_exactly(_HDR.size, deadline))
payload = self._read_exactly(ln, deadline) if ln else b""
got = got.rstrip(b"\0")
if got != cmd:
raise WorkerError("%s: expected %r, got %r" % (self.kind, cmd, got))
return payload
def _signal(self, sig):
try:
os.killpg(self.proc.pid, sig)
except OSError:
pass
def tree_pids(self, refresh=False):
"""The child's own process tree, including anything it started itself."""
if self._pids is not None and not refresh:
return self._pids
seen, stack = [], [self.proc.pid]
while stack:
pid = stack.pop()
seen.append(pid)
try:
for tid in os.listdir("/proc/%d/task" % pid):
with open("/proc/%d/task/%s/children" % (pid, tid)) as fh:
stack.extend(int(v) for v in fh.read().split())
except (OSError, ValueError):
pass
self._pids = seen
return seen
def freeze(self):
"""SIGSTOP, then wait until every thread has really stopped.
Returning early would let this child's threads -- BLAS worker threads busy-spin
for a while after the last call returns -- drain into the other child's timed
region, which would bias whichever executor is measured second.
"""
if not self.stopped:
self._signal(signal.SIGSTOP)
self.stopped = True
deadline = time.monotonic() + 2.0
while not _tasks_stopped(self.tree_pids()):
if time.monotonic() > deadline:
break
time.sleep(0.0002)
def thaw(self):
if self.stopped:
self._signal(signal.SIGCONT)
self.stopped = False
self._send(b"PING")
self._expect(b"PONG", CALL_TIMEOUT_SEC)
def build(self, seed):
t0 = time.perf_counter()
self._send(b"BLD", str(int(seed)).encode())
self._expect(b"RDY", BUILD_TIMEOUT_SEC)
return time.perf_counter() - t0
def call(self, xb):
"""Round-trip one input. Returns (seconds, header, raw output bytes)."""
t0 = time.perf_counter()
self._send(b"CALL", xb)
payload = self._expect(b"OUT", CALL_TIMEOUT_SEC)
dt = time.perf_counter() - t0
head, _, body = payload.partition(b"|")
return dt, head.decode("utf-8", "replace"), body
def stderr_tail(self, limit=2000):
self._signal(signal.SIGCONT)
self._signal(signal.SIGKILL)
try:
return self.proc.stderr.read().decode("utf-8", "replace")[-limit:]
except Exception:
return ""
def close(self):
self._signal(signal.SIGCONT)
self.stopped = False
try:
self._send(b"EXIT")
self.proc.wait(timeout=10)
except Exception:
self._signal(signal.SIGKILL)
try:
self.proc.wait(timeout=10)
except subprocess.TimeoutExpired:
pass
for stream in (self.proc.stdin, self.proc.stdout, self.proc.stderr):
try:
stream.close()
except Exception:
pass
def _quiesce(active):
"""Stop every unprivileged process that is not part of `active`'s tree.
An executor that detaches a helper into its own session would otherwise keep burning
cycles while the other executor is on the clock. Only the privileged harness can do
this, so the developer-side harness (which runs unprivileged) skips it; the minimum
statistic is what protects a measurement there.
"""
if os.geteuid() != 0:
return 0
keep_pids = set(active.tree_pids(refresh=True))
strays = 0
try:
pids = [int(p) for p in os.listdir("/proc") if p.isdigit()]
except OSError:
return 0
for pid in pids:
if pid in keep_pids or _uid_of(pid) != AGENT_UID:
continue
try:
os.kill(pid, signal.SIGSTOP)
strays += 1
except OSError:
pass
return strays
def _check_output(head, body, spec):
"""Validate a returned tensor. Returns the array or raises WorkerError."""
T, d = spec["T"], spec["d_model"]
try:
ndim, dtype, dims = head.split(",")
dims = tuple(int(v) for v in dims.split("x")) if dims else ()
except ValueError:
raise WorkerError("unparseable output header %r" % head)
if int(ndim) != 2 or dims != (T, d):
raise WorkerError("output shape %r, expected (%d, %d)" % (dims, T, d))
if dtype != "float32":
raise WorkerError("output dtype %r, expected float32" % dtype)
if len(body) != T * d * 4:
raise WorkerError("output payload is %d bytes, expected %d"
% (len(body), T * d * 4))
return np.frombuffer(body, dtype=np.float32).reshape(T, d)
def _errors(y, y_ref):
a = y.astype(np.float64)
b = y_ref.astype(np.float64)
if not np.all(np.isfinite(a)):
return float("inf"), float("inf")
diff = np.abs(a - b)
max_abs = float(diff.max()) if diff.size else 0.0
denom = float(np.linalg.norm(b))
rel = float(np.linalg.norm(diff) / denom) if denom > 0 else max_abs
return max_abs, rel
def measure_instance(seed, ref, sub, warmups=WARMUPS, reps=REPS):
"""Time one instance. Returns a record; raises WorkerError on any child failure."""
spec = graph_spec.sample_spec(seed)
xbs = [np.ascontiguousarray(x).tobytes()
for x in graph_spec.build_inputs(spec, warmups + reps)]
ref.freeze()
sub.thaw()
build_sub = sub.build(seed)
sub.freeze()
ref.thaw()
build_ref = ref.build(seed)
ref.freeze()
times = {id(ref): [], id(sub): []}
max_abs = 0.0
max_rel = 0.0
strays = 0
for i, xb in enumerate(xbs):
first, second = (ref, sub) if i % 2 == 0 else (sub, ref)
got = {}
for child in (first, second):
other = sub if child is ref else ref
other.freeze()
strays += _quiesce(child)
child.thaw()
dt, head, body = child.call(xb)
child.freeze()
got[id(child)] = (dt, head, body)
y_ref = _check_output(got[id(ref)][1], got[id(ref)][2], spec)
y_sub = _check_output(got[id(sub)][1], got[id(sub)][2], spec)
a, r = _errors(y_sub, y_ref)
max_abs = max(max_abs, a)
max_rel = max(max_rel, r)
if i >= warmups:
times[id(ref)].append(got[id(ref)][0])
times[id(sub)].append(got[id(sub)][0])
ref_t, sub_t = times[id(ref)], times[id(sub)]
ref_best, sub_best = min(ref_t), min(sub_t)
equivalent = bool(max_abs <= ABS_TOL and max_rel <= REL_TOL)
return {
"seed": int(seed),
"shape": {k: spec[k] for k in
("d_model", "d_ff", "n_layers", "n_heads", "n_kv_heads", "T")},
"ref_best_s": ref_best,
"sub_best_s": sub_best,
"ref_median_s": statistics.median(ref_t),
"sub_median_s": statistics.median(sub_t),
"ref_jitter": statistics.median(ref_t) / ref_best - 1.0,
"sub_jitter": statistics.median(sub_t) / sub_best - 1.0,
"build_ref_s": build_ref,
"build_sub_s": build_sub,
"strays_stopped": strays,
"max_abs_err": max_abs,
"rel_fro_err": max_rel,
"equivalent": equivalent,
"ratio": (ref_best / sub_best) if (equivalent and sub_best > 0) else 0.0,
}
def child_env():
"""The environment both children get. BLAS gets the full worker budget."""
return {
"PATH": "/usr/local/bin:/usr/local/sbin:/usr/sbin:/usr/bin:/sbin:/bin",
"HOME": "/tmp",
"LANG": "C.UTF-8",
"PYTHONDONTWRITEBYTECODE": "1",
"PYTHONHASHSEED": "0",
"OPENBLAS_NUM_THREADS": str(N_WORKERS),
"OMP_NUM_THREADS": str(N_WORKERS),
"MKL_NUM_THREADS": str(N_WORKERS),
"NUMEXPR_NUM_THREADS": str(N_WORKERS),
"EXEC_N_WORKERS": str(N_WORKERS),
"EXEC_N_CPUS": str(N_CPUS),
}
def measure(seeds, rundir, python=sys.executable, launch_prefix=(),
popen_kwargs=None):
"""Measure every instance and aggregate. Returns the metric record."""
env = child_env()
ref = sub = None
per_instance = []
failure = None
stderr_tail = ""
try:
ref = Child("ref", rundir, python, (), env, None)
sub = Child("sub", rundir, python, launch_prefix, env, popen_kwargs)
for seed in seeds:
per_instance.append(measure_instance(int(seed), ref, sub))
except WorkerError as exc:
failure = str(exc)
except Exception as exc:
failure = "%s: %s" % (type(exc).__name__, exc)
finally:
if failure is not None and sub is not None:
stderr_tail = sub.stderr_tail()
for child in (ref, sub):
if child is not None:
try:
child.close()
except Exception:
pass
n_ok = sum(1 for r in per_instance if r["equivalent"])
valid = bool(failure is None and len(per_instance) == len(seeds) == n_ok)
if valid:
metric = math.exp(
sum(math.log(r["ratio"]) for r in per_instance) / len(per_instance))
else:
metric = 0.0
return {
"metric_name": "geometric_mean_speedup",
"metric": metric,
"valid": valid,
"failure": failure,
"stderr_tail": stderr_tail,
"n_instances": len(seeds),
"n_equivalent": n_ok,
"per_instance": per_instance,
}
def dump(record, path):
with open(path, "w") as fh:
json.dump(record, fh, indent=2, sort_keys=True)
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