analytical-viz: auto_hardware.py — joint HW×parallelism explore

New module extends auto_explore into the hardware co-design space. For a
fixed model + workload, sweeps hardware knobs (pe_hbm_gb, bw_hbm_gbs,
peak_tflops_f16, bw_intra_gbs, bw_inter_gbs, bw_intersip_gbs) and, for
each hardware candidate, searches parallelism for the latency-minimum
that fits memory. Returns:

  - all_scores: every (hw, parallelism) pair that fits, sorted by latency
  - pareto_scores: 2D Pareto frontier on (latency ↓, cost_score ↓)
  - sensitivity: per-knob rel_speedup when doubled from the best-fast HW
    baseline. Ranks which HW knob gives the biggest speedup — a co-design
    signal.

Three sweep depths trade coverage for time:
  - two_stage: 1 HW candidate (defaults) × autosuggest's memory-min
    parallelism. Fast (~1s), useful for the sensitivity ranking alone.
  - balanced: 64 HW × ~2k reduced-parallelism configs = ~130k joint evals,
    ~10-20s. Default UI setting.
  - coarse:   729 HW × ~2k configs = ~1.4M joint evals, ~2-5 min.

Reduced parallelism sweep for the inner loop: CP × TP × PP × DP ×
kv_shard_mode (1,920 configs), other 4 knobs held at latency-friendly
defaults (ffn_shard_scope='TP+CP', tp_placement='cube', cp_placement='pe',
cp_ring_variant='qoml' for decode, 'kv' for prefill). Full 28,800-config
auto_explore per HW would take 6+ minutes — too slow.

Cost proxy: sum of (knob / knob_default). 6.0 at defaults. Not dollars —
a rough capability score where higher = "more spec'd hardware".

Verified:
- 9 pytest tests pass:
    * enumeration counts match expected (1, 64, 729)
    * default cost_score = 6.0
    * Pareto non-dominated + subset of all_scores
    * every knob is monotone-non-worsening when doubled
    * for Llama 70B decode, bw_hbm_gbs tops the sensitivity ranking
      (physically correct: memory-bound workload)
- Smoke: Llama 70B decode 128K balanced sweep in ~20s produces
  5 Pareto configs; best 7.57 ms with 1024 GB/s HBM BW. Doubling
  HBM BW gives 33% additional speedup; every other knob < 1.5%.

Next: Streamlit UI tab consuming this in Commit 5.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
This commit is contained in:
2026-07-28 13:16:40 -07:00
parent 2834383700
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"""Joint hardware × parallelism exploration.
For a fixed model + workload, sweep both:
- hardware parameters (MachineParams: pe_hbm_gb, bw_hbm_gbs, peak_tflops_f16,
bw_intra_gbs, bw_inter_gbs, bw_intersip_gbs), and
- parallelism knobs (a reduced subset of auto_explore's 9 knobs)
Then rank on:
- latency ↓
- hardware cost proxy ↓ (normalized sum of knob-over-default)
Also computes per-knob sensitivity — how much latency drops when each
hardware knob is doubled from its baseline value. Useful for HW co-design
("which knob to invest in first?").
The default 'balanced' depth: 64 HW candidates × ~2k parallelism configs =
~130k joint evaluations, ~1-5 s at analytical speeds. Coarse and
two-stage variants trade coverage for speed.
"""
from __future__ import annotations
import math
from collections.abc import Iterator
from dataclasses import dataclass, field, replace
from .auto_explore import ConfigScore, score_config
from .autosuggest import auto_suggest
from .memory_layout import compute_memory
from .model_config import FullConfig, MachineParams, ModelConfig, TopologyConfig
# ── Hardware search space ────────────────────────────────────────────
#
# For each depth level, values per knob. Defaults are always included so the
# baseline configuration always appears in the sweep.
_HW_KNOB_DEFAULTS = {
"pe_hbm_gb": 6.0,
"bw_hbm_gbs": 256.0,
"peak_tflops_f16": 8.0,
"bw_intra_gbs": 512.0,
"bw_inter_gbs": 128.0,
"bw_intersip_gbs": 50.0,
}
_HW_VALUES_BALANCED = {
"pe_hbm_gb": [6.0, 12.0],
"bw_hbm_gbs": [256.0, 512.0],
"peak_tflops_f16": [8.0, 16.0],
"bw_intra_gbs": [512.0, 1024.0],
"bw_inter_gbs": [128.0, 256.0],
"bw_intersip_gbs": [50.0, 100.0],
}
_HW_VALUES_COARSE = {
"pe_hbm_gb": [6.0, 12.0, 24.0],
"bw_hbm_gbs": [256.0, 512.0, 1024.0],
"peak_tflops_f16": [8.0, 16.0, 32.0],
"bw_intra_gbs": [512.0, 1024.0, 2048.0],
"bw_inter_gbs": [128.0, 256.0, 512.0],
"bw_intersip_gbs": [50.0, 100.0, 200.0],
}
# For sensitivity: "double each knob independently from baseline."
_SENSITIVITY_KNOBS = list(_HW_KNOB_DEFAULTS.keys())
# ── Reduced parallelism search space (for per-HW inner loop) ─────────
#
# The full auto_explore has 28,800 configs; using it inside a HW loop is
# too slow. Reduce to CP × TP × PP × DP × kv_shard_mode with common
# defaults for the remaining 4 knobs (~2k configs).
_CP_OPTIONS = (1, 2, 4, 8, 16, 32, 64, 96)
_TP_OPTIONS = (1, 2, 4, 8, 16, 32)
_PP_OPTIONS = (1, 2, 4, 8, 16)
_DP_OPTIONS = (1, 2, 4)
_KV_SHARD_MODES = ("split", "replicate")
# ── Result types ─────────────────────────────────────────────────────
@dataclass
class HardwareCandidate:
pe_hbm_gb: float
bw_hbm_gbs: float
peak_tflops_f16: float
bw_intra_gbs: float
bw_inter_gbs: float
bw_intersip_gbs: float
def as_machine(self) -> MachineParams:
"""Build a MachineParams from this HW candidate, holding alphas +
compute_util at their MachineParams defaults."""
return MachineParams(
pe_hbm_gb=self.pe_hbm_gb,
bw_hbm_gbs=self.bw_hbm_gbs,
peak_tflops_f16=self.peak_tflops_f16,
bw_intra_gbs=self.bw_intra_gbs,
bw_inter_gbs=self.bw_inter_gbs,
bw_intersip_gbs=self.bw_intersip_gbs,
)
@property
def cost_score(self) -> float:
"""Normalized cost proxy: sum of (knob / default). 6.0 at defaults.
This is NOT dollars — it's a rough silicon-area / capability proxy. A
higher cost_score means "more capable hardware" (more HBM, faster BW,
etc.). Under identical latency, lower cost_score wins.
"""
return sum(
getattr(self, k) / _HW_KNOB_DEFAULTS[k]
for k in _HW_KNOB_DEFAULTS
)
@dataclass
class JointScore:
"""One (hardware, parallelism) pair with its computed latency + cost."""
hardware: HardwareCandidate
parallelism: ConfigScore
total_latency_ns: float
cost_score: float
@property
def latency_ms(self) -> float:
return self.total_latency_ns / 1e6
@dataclass
class SensitivityRow:
knob: str
baseline_value: float
doubled_value: float
baseline_latency_ns: float
doubled_latency_ns: float
@property
def rel_speedup(self) -> float:
"""1 - (doubled/baseline). Positive = doubling this knob speeds things up."""
if self.baseline_latency_ns <= 0:
return 0.0
return 1.0 - (self.doubled_latency_ns / self.baseline_latency_ns)
@dataclass
class JointExploreResult:
model_name: str
s_kv: int
mode: str
depth: str
total_hw: int
total_joint: int
all_scores: list[JointScore] = field(default_factory=list)
pareto_scores: list[JointScore] = field(default_factory=list)
sensitivity: list[SensitivityRow] = field(default_factory=list)
# ── Hardware enumeration ─────────────────────────────────────────────
def enumerate_hardware(depth: str = "balanced") -> Iterator[HardwareCandidate]:
"""Yield HardwareCandidates for the given sweep depth.
depth ∈ {"two_stage", "balanced", "coarse"}:
- two_stage: only the default HW (1 candidate; parallelism sweep dominates)
- balanced: 2 values per knob → 2^6 = 64 candidates
- coarse: 3 values per knob → 3^6 = 729 candidates
"""
if depth == "two_stage":
vals = {k: [v] for k, v in _HW_KNOB_DEFAULTS.items()}
elif depth == "coarse":
vals = _HW_VALUES_COARSE
else: # balanced (default)
vals = _HW_VALUES_BALANCED
for pe_hbm in vals["pe_hbm_gb"]:
for bw_hbm in vals["bw_hbm_gbs"]:
for tflops in vals["peak_tflops_f16"]:
for bw_intra in vals["bw_intra_gbs"]:
for bw_inter in vals["bw_inter_gbs"]:
for bw_intersip in vals["bw_intersip_gbs"]:
yield HardwareCandidate(
pe_hbm_gb=pe_hbm,
bw_hbm_gbs=bw_hbm,
peak_tflops_f16=tflops,
bw_intra_gbs=bw_intra,
bw_inter_gbs=bw_inter,
bw_intersip_gbs=bw_intersip,
)
# ── Reduced parallelism search per HW ────────────────────────────────
def _iter_reduced_parallelism(
model: ModelConfig, s_kv: int, mode: str,
) -> Iterator[TopologyConfig]:
"""Reduced sweep: CP × TP × PP × DP × kv_shard_mode.
Other 4 knobs held at defaults chosen to be latency-friendly for the
decode/prefill common case:
- ffn_shard_scope = "TP+CP" (common good choice; trades a small AR
for lower per-PE weight bytes)
- tp_placement = "cube" (packs TP across cubes; UCIe D2D)
- cp_placement = "pe" (packs CP inside cubes; intra NoC)
- cp_ring_variant = "qoml" for decode, "kv" for prefill
Total: 8 × 6 × 5 × 4 × 2 = 1,920 configs per HW candidate.
"""
cp_ring = "qoml" if mode == "decode" else "kv"
for cp in _CP_OPTIONS:
for tp in _TP_OPTIONS:
if tp > 4 * model.h_q:
continue
for pp in _PP_OPTIONS:
if pp > model.layers:
continue
for dp in _DP_OPTIONS:
for kv_mode in _KV_SHARD_MODES:
# cp_ring=qoml with cp=1 is a no-op; fall back to kv.
ring = "kv" if cp == 1 else cp_ring
yield TopologyConfig(
cp=cp, tp=tp, pp=pp, dp=dp,
s_kv=s_kv, mode=mode,
kv_shard_mode=kv_mode,
ffn_shard_scope="TP+CP",
tp_placement="cube",
cp_placement="pe",
cp_ring_variant=ring,
)
def _best_parallelism_for_hw(
model: ModelConfig, machine: MachineParams,
s_kv: int, mode: str,
) -> ConfigScore | None:
"""Return the latency-minimum feasible parallelism for this HW.
Feasibility: fits memory + placement_valid. Returns None if nothing fits.
"""
best: ConfigScore | None = None
for topo in _iter_reduced_parallelism(model, s_kv, mode):
cfg = FullConfig(model=model, topo=topo, machine=machine)
s = score_config(cfg)
if not (s.fits_memory and s.placement_valid):
continue
if best is None or s.total_latency_ns < best.total_latency_ns:
best = s
return best
def _best_parallelism_two_stage(
model: ModelConfig, machine: MachineParams,
s_kv: int, mode: str,
) -> ConfigScore | None:
"""Fast fallback: use autosuggest's memory-min (CP,TP,PP) then score it."""
sug = auto_suggest(model, machine, s_kv, mode)
if not sug.fits:
return None
topo = TopologyConfig(
cp=sug.cp, tp=sug.tp, pp=sug.pp, dp=1,
s_kv=s_kv, mode=mode,
kv_shard_mode="split",
ffn_shard_scope="TP+CP",
tp_placement="cube",
cp_placement="pe",
cp_ring_variant="qoml" if mode == "decode" and sug.cp > 1 else "kv",
)
cfg = FullConfig(model=model, topo=topo, machine=machine)
s = score_config(cfg)
return s if s.fits_memory and s.placement_valid else None
# ── Pareto over joint (latency, cost) ────────────────────────────────
def _pareto_2d(scores: list[JointScore]) -> list[JointScore]:
"""Non-dominated set on (total_latency_ns ↓, cost_score ↓). O(N²)."""
frontier: list[JointScore] = []
for i, a in enumerate(scores):
dominated = False
for j, b in enumerate(scores):
if i == j:
continue
no_worse = (
b.total_latency_ns <= a.total_latency_ns
and b.cost_score <= a.cost_score
)
strictly_better = (
b.total_latency_ns < a.total_latency_ns
or b.cost_score < a.cost_score
)
if no_worse and strictly_better:
dominated = True
break
if not dominated:
frontier.append(a)
return frontier
# ── Per-knob sensitivity ─────────────────────────────────────────────
def compute_sensitivity(
baseline_hw: HardwareCandidate,
parallelism: ConfigScore,
model: ModelConfig, s_kv: int, mode: str,
) -> list[SensitivityRow]:
"""For each HW knob, double it (holding others at baseline) and measure
the latency change. Same parallelism used throughout so we isolate the
HW knob's effect."""
rows: list[SensitivityRow] = []
baseline_machine = baseline_hw.as_machine()
baseline_topo = parallelism.as_topology(s_kv, mode)
baseline_cfg = FullConfig(
model=model, topo=baseline_topo, machine=baseline_machine,
)
baseline_score = score_config(baseline_cfg)
baseline_latency = baseline_score.total_latency_ns
for knob in _SENSITIVITY_KNOBS:
doubled_val = 2.0 * getattr(baseline_hw, knob)
doubled_hw = replace(baseline_hw, **{knob: doubled_val})
doubled_cfg = FullConfig(
model=model, topo=baseline_topo, machine=doubled_hw.as_machine(),
)
doubled_score = score_config(doubled_cfg)
rows.append(SensitivityRow(
knob=knob,
baseline_value=getattr(baseline_hw, knob),
doubled_value=doubled_val,
baseline_latency_ns=baseline_latency,
doubled_latency_ns=doubled_score.total_latency_ns,
))
# Sort by biggest speedup first (most sensitive knob at the top).
rows.sort(key=lambda r: -r.rel_speedup)
return rows
# ── Top-level driver ─────────────────────────────────────────────────
def joint_explore(
model: ModelConfig,
s_kv: int,
mode: str,
depth: str = "balanced",
) -> JointExploreResult:
"""Sweep HW candidates × parallelism, return joint Pareto + sensitivity.
Sensitivity is computed around the LATENCY-MINIMUM joint point (the
"best fast" config), doubling each HW knob one at a time.
"""
all_scores: list[JointScore] = []
for hw in enumerate_hardware(depth):
machine = hw.as_machine()
if depth == "two_stage":
par = _best_parallelism_two_stage(model, machine, s_kv, mode)
else:
par = _best_parallelism_for_hw(model, machine, s_kv, mode)
if par is None:
continue
all_scores.append(JointScore(
hardware=hw,
parallelism=par,
total_latency_ns=par.total_latency_ns,
cost_score=hw.cost_score,
))
all_scores.sort(key=lambda s: s.total_latency_ns)
pareto = _pareto_2d(all_scores)
pareto.sort(key=lambda s: s.total_latency_ns)
sensitivity: list[SensitivityRow] = []
if all_scores:
best = all_scores[0]
sensitivity = compute_sensitivity(
best.hardware, best.parallelism, model, s_kv, mode,
)
return JointExploreResult(
model_name=model.name,
s_kv=s_kv,
mode=mode,
depth=depth,
total_hw=sum(1 for _ in enumerate_hardware(depth)),
total_joint=len(all_scores),
all_scores=all_scores,
pareto_scores=pareto,
sensitivity=sensitivity,
)