Merge branch 'linus/analysis' into 'main'

Linus/analysis

See merge request course-asl-fastcode26/team70!43

analysis/make_csv.py

@@ -0,0 +1,67 @@
+import os
+import re
+import csv
+
+# folder that holds one subfolder per variant, each with an x86/ dir full of *.log files
+ROOT = "measurements"
+OUT = "analysis/results.csv"
+
+# the benchmark prints one block per problem size, looks like:
+#   === N_P=500 N_ITER=200 ===
+#   W(n) per iteration: ...
+#   Q(n) per iteration: ...
+#   I(n): ...
+#   W(n): ...
+#   T(n): ...            <- cycles
+#   P(n): ...            <- flops/cycle
+# so I split each log on the "=== N_P=.. ===" lines and read the fields out of each block.
+size_line = re.compile(r"=== N_P=(\d+) N_ITER=(\d+) ===")
+
+def num(pattern, text):
+    m = re.search(pattern, text)
+    if m:
+        return float(m.group(1))
+    return None
+
+#we run every variant a few times (1.log, 2.log, ...). keep the fastest run per size,
+#min cycles is the standard way to kill the OS/turbo noise.
+best = {}
+
+for variant in sorted(os.listdir(ROOT)):
+    logdir = os.path.join(ROOT, variant, "x86")
+    if not os.path.isdir(logdir):
+        continue
+
+    for fn in os.listdir(logdir):
+        if not fn.endswith(".log"):
+            continue
+        text = open(os.path.join(logdir, fn)).read()
+
+        marks = list(size_line.finditer(text))
+        for i, m in enumerate(marks):
+            n = int(m.group(1))
+            n_iter = int(m.group(2))
+            start = m.end()
+            stop = marks[i + 1].start() if i + 1 < len(marks) else len(text)
+            block = text[start:stop]
+
+            cycles = num(r"T\(n\):\s*([\d.]+)", block)
+            if cycles is None:
+                continue
+            W = num(r"W\(n\):\s*([\d.]+)", block)
+
+            key = (variant, n)
+            if key not in best or cycles < best[key][2]:
+                best[key] = (variant, n, cycles, n_iter, W,
+                             num(r"Q\(n\) per iteration:\s*([\d.]+)", block),
+                             num(r"I\(n\):\s*([\d.]+)", block))
+
+with open(OUT, "w", newline="") as f:
+    w = csv.writer(f)
+    w.writerow(["variant", "n", "n_iter", "W", "Q_per_iter", "I", "cycles", "flops_per_cycle"])
+    for variant, n in sorted(best):
+        _, _, cycles, n_iter, W, q, I = best[(variant, n)]
+        fc = W / cycles
+        w.writerow([variant, n, n_iter, W, q, I, round(cycles, 1), round(fc, 3)])
+
+print("wrote", OUT, "with", len(best), "rows")

analysis/plots.py

@@ -0,0 +1,144 @@
+import pandas as pd
+import numpy as np
+import matplotlib.pyplot as plt
+#import seaborn as sns   # tried it, the default look was worse
+
+df = pd.read_csv("analysis/results.csv")
+
+# peaks for the ryzen ai 7 350 (zen5) at 2GHz. 2 fma units and the datapath is 256 bit
+# -> scalar 4, double 16, float 32 flops/cycle
+SCALAR = 4
+PEAK_D = 16
+PEAK_F = 32
+maroon = "#A71D5B"
+
+def get(v, n=5000):
+    return df[(df.variant==v) & (df.n==n)]["flops_per_cycle"].values[0]
+
+def getline(v):
+    s = df[df.variant == v].sort_values("n")
+    return s.n.values, s["flops_per_cycle"].values
+
+base = get("variant_baseline")
+
+
+# plot 1: the two precision tracks (this is the main results plot)
+# double tops out ~7, float goes to 24. also shows the avx2-float stuff already does most of the work
+tracks = [
+ ("variant_inlining_7_SoA_AVX2", "double, AVX2", "#9bbbe0", "--"),
+ ("variant_inlining_8_SoA_AVX512_polyexp_moreavx", "double, AVX-512 + polyexp", "#2f5d9e", "-"),
+ ("variant_float_inlining_SoA_AVX2_polyexp", "float, AVX2 + polyexp", "#e58aa6", "--"),
+ ("variant_float_inlining_SoA_AVX2_polyexp_rsqrt_loopopt", "float, AVX2 + polyexp + rsqrt", "#d05a82", "--"),
+ ("variant_float_inlining_SoA_AVX512_polyexp_moreavx_ilp_2_rsqrt_morersqrt", "float, AVX-512 + rsqrt + ILP (best)", maroon, "-"),
+]
+
+fig, ax = plt.subplots(figsize=(9,4.7))
+for v,lab,c,ls in tracks:
+    x,y = getline(v)
+    ax.plot(x, y, ls, color=c, marker="o", ms=4, lw= 2.4 if c==maroon else 1.8, label=lab)
+
+for yv,t in [(PEAK_D,"double peak (16)"), (PEAK_F,"float peak (32)")]:
+    ax.axhline(yv, ls=":", color="#999", lw=1.2)
+    ax.text(52, yv*1.03, t, fontsize=9.5, color="#888")
+
+ax.set_xscale("log"); ax.set_yscale("log")
+ax.set_xticks([50,100,200,500,1000,2000,5000,10000])
+ax.set_xticklabels(["50","100","200","500","1k","2k","5k","10k"])
+ax.set_yticks([1,2,4,8,16,32]); ax.set_yticklabels(["1","2","4","8","16","32"])
+ax.set_xlim(46,13000); ax.set_ylim(1,40)
+ax.set_xlabel("number of pedestrians  n")
+ax.set_ylabel("performance [flops/cycle]")
+ax.grid(color="#e9e9e9")
+ax.spines["top"].set_visible(False); ax.spines["right"].set_visible(False)
+ax.legend(fontsize=9, loc="lower left", framealpha=.95)
+plt.tight_layout()
+plt.savefig("analysis/fig_tracks.png", dpi=170, bbox_inches="tight")
+
+
+# plot 2: all te milestones + the symmetry one that got slower 
+bars = [
+ ("baseline", "variant_baseline"),
+ ("AVX2 (double)", "variant_inlining_7_SoA_AVX2"),
+ ("AVX-512 (double)", "variant_avx512_1"),
+ ("+ polyexp", "variant_inlining_8_SoA_AVX512_polyexp_moreavx"),
+ ("+ float", "variant_float_inlining_SoA_AVX512_polyexp_moreavx"),
+ ("+ rsqrt & ILP", "variant_float_inlining_SoA_AVX512_polyexp_moreavx_ilp_2_rsqrt_morersqrt"),
+ ("symmetry\n(half the pairs)", "variant_inlining_7_symmetry_2"),
+]
+names = [b[0] for b in bars]
+spd   = [get(b[1])/base for b in bars]
+cols  = ["#7a7a7a","#3b6fb0","#2f9e8f","#e08a1e","#c0436a", maroon, "#cf2b2b"]
+
+fig,ax = plt.subplots(figsize=(9,4.7))
+yp = np.arange(len(names))[::-1]
+ax.barh(yp, spd, color=cols, height=0.66)
+for yy,s in zip(yp,spd):
+    ax.text(s+0.25, yy, str(round(s,1))+"x", va="center", fontsize=11, fontweight="bold",
+            color = "#cf2b2b" if s<1 else "#222")
+ax.axvline(1, ls="--", color="#888", lw=1)
+ax.set_yticks(yp); ax.set_yticklabels(names)
+ax.set_xlim(0,26)
+ax.set_xlabel("speedup over baseline  (n=5000)")
+#ax.set_title("optimization milestones (and the one that backfired)", loc="left", fontsize=13)
+ax.grid(axis="x", color="#eee"); ax.grid(axis="y", visible=False)
+ax.spines["top"].set_visible(False); ax.spines["right"].set_visible(False)
+plt.tight_layout()
+plt.savefig("analysis/fig_ladder.png", dpi=170, bbox_inches="tight")
+
+
+# plot3 roofline
+# every variant has the same I at a given n (W and Q dont change between variants), so the
+# points just stack vertically. we're miles to the right of the ridge -> compute bound.
+fig,ax = plt.subplots(figsize=(9,4.7))
+bw = 60      # bytes/cycle, ~120 GB/s lpddr5x / 2GHz. rough
+xx = np.logspace(-1, 3.6, 200)
+ax.plot(xx, np.minimum(bw*xx, PEAK_F), color="#cccccc", lw=1.2)
+
+for pk,t in [(SCALAR,"scalar (4)"),(PEAK_D,"double (16)"),(PEAK_F,"float (32)")]:
+    ax.axhline(pk, ls="--", color="#999", lw=1.1)
+    ax.text(0.11, pk*1.04, t+" peak", fontsize=9.5, color="#888")
+
+I5000 = df[(df.variant=="variant_baseline") & (df.n==5000)]["I"].values[0]
+pts = [
+ ("variant_baseline", "#7a7a7a"),
+ ("variant_avx512_1", "#2f9e8f"),
+ ("variant_inlining_8_SoA_AVX512_polyexp_moreavx", "#e08a1e"),
+ ("variant_float_inlining_SoA_AVX512_polyexp_moreavx", "#c0436a"),
+ ("variant_float_inlining_SoA_AVX512_polyexp_moreavx_ilp_2_rsqrt_morersqrt", maroon),
+]
+for v,c in pts:
+    ax.plot(I5000, get(v), "o", ms=9, color=c, mec="white", mew=1)
+
+
+ax.text(I5000, 1.3, "n=5000", fontsize=10, color="#555")
+
+ax.set_xscale("log"); ax.set_yscale("log")
+ax.set_xlim(0.1, 6500); ax.set_ylim(0.7, 45)
+ax.set_xlabel("operational intensity  I  [flops/byte]")
+ax.set_ylabel("performance [flops/cycle]")
+#ax.set_title("roofline: deeply compute-bound (I grows with n; work O(n^2), data O(n))", loc="left", fontsize=12)
+ax.grid(color="#ededed")
+ax.spines["top"].set_visible(False); ax.spines["right"].set_visible(False)
+plt.tight_layout()
+plt.savefig("analysis/fig_roofline.png", dpi=170, bbox_inches="tight")
+
+
+# plot 4: exp vs the polynomial approx (just to show its basically exact) 
+x = np.linspace(-6, 0, 300)
+ex = np.exp(x)
+co = np.polyfit(x, ex, 5)        # degree 5 same as in the kernel
+ap = np.polyval(co, x)
+
+fig,ax = plt.subplots(figsize=(4.6,3.7))
+ax.plot(x, ex, color="#222", lw=2.4, label="exp(x)")
+ax.plot(x, ap, "--", color=maroon, lw=2, label="poly approx")
+ax.set_xlabel("x")
+ax.set_title("exp -> polynomial", loc="left", fontsize=12)
+ax.grid(color="#ededed")
+ax.spines["top"].set_visible(False); ax.spines["right"].set_visible(False)
+ax.legend(frameon=False, fontsize=10)
+plt.tight_layout()
+plt.savefig("analysis/fig_exp.png", dpi=170, bbox_inches="tight")
+
+#plt.show()
+print("done")