amorfo77/json
1
0 Fork 0
mirror of https://github.com/nlohmann/json.git synced 2026-11-04 11:49:22 +00:00
Code Issues Packages Projects Releases Wiki Activity
Files
7341f127d3b3db27b40a8f209ea03332e9a2ce61
json/docs/mkdocs/scripts/figures/perf_blog.py
T
Niels Lohmann 7341f127d3 docs: compare json_document with Glaze, sonic, RapidJSON and Rust parsers 
Extends the comparison in "How 3.13.0 got faster" from yyjson, simdjson and
Boost.JSON to eleven engines: sonic-cpp, RapidJSON and Glaze (generic DOM,
lazy_json, reading into structs) in C++, sonic-rs, simd-json and serde_json in
Rust. Measured on an Apple M1 Max (Apple clang 21, Rust 1.99) and an x86-64
Haswell server (GCC 13, Clang 18). Every engine must return the same values,
string bytes and bit-identical number sums before it is timed.

The post now answers whether json_document is the fastest parser: it is the
fastest document parser at parse+dump everywhere and at parsing on Apple
silicon, ties with simdjson's DOM on x86-64, and loses to simdjson On-Demand
and Glaze structs when only a few fields are read.

tests/benchmarks/json_view/others holds the programs (bench_all.cpp, the Rust
crate with its Cargo.lock), summarize.py and the pinned versions and checksums.

Signed-off-by: Niels Lohmann <mail@nlohmann.me>
2026-10-30 15:29:46 +01:00

366 lines
19 KiB
Python
Raw Blame History

"""Draws the figures of home/blog/how_3_13_0_got_faster.md as inline SVGs into docs/images/.
Generated files:
- perf_blog_overview.svg: speedup of 3.13.0 over 3.12.0 per workload (Google Benchmark suite)
- perf_blog_timeline_<workload>.svg: speedup over 3.12.0 of eight workloads at every develop commit that changed
json.hpp or json_view.hpp since 3.12.0, one panel each
- perf_blog_swar.svg: the eight-byte string test on one word of input
- perf_blog_cliffs.svg: operations that were quadratic or worse, 3.12.0 against 3.13.0 (log scale)
- perf_blog_view.svg: parse throughput of json_document and six other document parsers
The numbers are copied from the tables of the post (the timeline from data/perf_timeline.csv, which
`tests/benchmarks/history/history.py summarize` writes); the tables stay on the page as the accessible fallback. Update both together.
Like the figures of charts.py, the SVGs are not images: the page includes their text with
`--8<-- "images/<name>.svg"`, so they follow the colours and fonts of the page (`nj-charts` rules in
docs/css/fig-charts.css, `nj-fig` rules in docs/css/brand.css). Run `python3 scripts/figures/perf_blog.py` from
docs/mkdocs after changing data or drawing, and commit the generated files.
"""
import csv
import html
import math
import re
from pathlib import Path
HERE = Path(__file__).resolve().parent
OUT = HERE.parents[1] / "docs" / "images"
MINUS = "&#8722;"
TIMES = "&#215;"
# words the abbreviation extension (includes/glossary.md) would wrap in <abbr> inside the SVG text
ABBR = re.compile(r"(?<![\w;])(BJData|BON8|BSON|CBOR|GCC|UBJSON|MsgPack|JSON|DOM|SAX|SIMD|UTF|ASCII)(?!\w)")
def protect(text):
return ABBR.sub(lambda m: m.group(1)[0] + "&#8203;" + m.group(1)[1:], text)
def esc(s):
return html.escape(s, quote=True).replace("&amp;#", "&#")
def write(name, W, H, cls, tid, title, desc, body):
s = ['<svg class="nj-fig nj-charts %s" viewBox="0 0 %g %g" role="img" aria-labelledby="%s %s-d" '
'xmlns="http://www.w3.org/2000/svg">' % (cls, W, H, tid, tid),
'<title id="%s">%s</title>' % (tid, esc(title)),
'<desc id="%s-d">%s</desc>' % (tid, esc(desc))]
s += body
s.append('</svg>')
text = protect("\n".join(s)) + "\n"
assert "\n\n" not in text # a blank line would end the raw HTML block
(OUT / name).write_text(text)
def hbar(x0, x1, y, h, r=4):
"""Horizontal bar from the baseline x0 to x1, rounded only at the data end."""
if abs(x1 - x0) < 0.5:
return "M%g %g h0.5 v%g h-0.5 Z" % (x0, y, h)
r = min(r, h / 2, abs(x1 - x0))
s = 1 if x1 > x0 else -1
return ("M%g %g H%g Q%g %g %g %g V%g Q%g %g %g %g H%g Z"
% (x0, y, x1 - s * r, x1, y, x1, y + r, y + h - r, x1, y + h, x1 - s * r, y + h, x0))
def fx(v):
"""speedup factor for labels: 2 significant digits below 10, integers above"""
if v >= 100:
return "%d%s" % (round(v), TIMES)
if v >= 10:
return "%.0f%s" % (v, TIMES)
return "%.1f%s" % (v, TIMES) if v >= 1.995 else "%.2f%s" % (v, TIMES)
# ---------- SWAR: one word of a string ----------
def swar():
text = 'witter",'
W, H = 640, 312
L, cw, top = 40, 70, 34
b = []
b.append('<text class="fg-h" x="%g" y="20">eight input bytes, loaded as one 64-bit word (byte 0 is the lowest)</text>' % L)
for i, ch in enumerate(text):
x = L + i * cw
special = ch == '"'
b.append('<rect class="fg-cell" x="%g" y="%g" width="%g" height="40" rx="4"/>' % (x, top, cw - 6))
if special:
b.append('<rect class="nj-charts-c2" fill-opacity=".25" x="%g" y="%g" width="%g" height="40" rx="4"/>' % (x, top, cw - 6))
b.append('<text class="fg-code" x="%g" y="%g" text-anchor="middle">%s</text>' % (x + (cw - 6) / 2, top + 26, esc(ch)))
b.append('<text class="nj-charts-tick" x="%g" y="%g">0x%02X</text>' % (x + (cw - 6) / 2, top + 58, ord(ch)))
b.append('<text class="nj-charts-tick" x="%g" y="%g">byte %d</text>' % (x + (cw - 6) / 2, top + 74, i))
# result row
y2 = top + 112
b.append('<text class="fg-h" x="%g" y="%g">swar_string_special(): the high bit of each byte that needs handling</text>' % (L, y2 - 14))
for i, ch in enumerate(text):
x = L + i * cw
special = ch == '"'
b.append('<rect class="fg-cell" x="%g" y="%g" width="%g" height="34" rx="4"/>' % (x, y2, cw - 6))
if special:
b.append('<rect class="nj-charts-c2" fill-opacity=".25" x="%g" y="%g" width="%g" height="34" rx="4"/>' % (x, y2, cw - 6))
b.append('<text class="fg-code" x="%g" y="%g" text-anchor="middle">%s</text>'
% (x + (cw - 6) / 2, y2 + 23, "0x80" if special else "0x00"))
# conclusion
y3 = y2 + 70
b.append('<text class="fg-code" x="%g" y="%g">count_trailing_zeros(0x0080000000000000) = 55</text>' % (L, y3))
b.append('<text class="fg-code" x="%g" y="%g">55 / 8 = 6: copy bytes 0 to 5 in one go, then handle the quote</text>' % (L, y3 + 26))
b.append('<text class="fg-note fg-note--l" x="%g" y="%g">No branch per byte: a few subtractions, ANDs and ORs per word,</text>' % (L, y3 + 56))
b.append('<text class="fg-note fg-note--l" x="%g" y="%g">then one count of trailing zeros.</text>' % (L, y3 + 74))
write("perf_blog_swar.svg", W, H, "nj-charts--swar", "nj-blog-swar",
"Finding the end of a run of ordinary string characters eight bytes at a time",
"The eight bytes w, i, t, t, e, r, quote and comma are loaded as one word. The test sets the high bit only in "
"byte 6, the quote. Counting trailing zero bits gives 55, divided by eight gives 6: bytes 0 to 5 are copied "
"at once, then the quote ends the string.", b)
# ---------- overview: speedup per workload (Google Benchmark rows, 3.12.0 time / 3.13.0 time) ----------
# (group, label, speedup), copied from the table "The short version"
OVERVIEW = [
("Parsing", "twitter.json", 3.02),
("Parsing", "citm_catalog.json", 4.13),
("Parsing", "canada.json", 3.46),
("Parsing", "canada.json, indented", 6.74),
("Parsing", "citm, ordered_json", 6.58),
("Parsing", "twitter, std::ifstream", 2.46),
("Parsing", "citm, FILE*", 4.76),
("Parsing", "citm, accept()", 6.99),
("Writing", "dump() twitter", 6.67),
("Writing", "dump() canada", 2.95),
("Writing", "dump(4) citm", 4.63),
("Writing", "to_cbor() twitter", 4.50),
("Reading CBOR", "twitter, memory", 3.11),
("Reading CBOR", "twitter, FILE*", 6.31),
("Values", "diff() canada", 10.44),
("Values", "iterate canada", 2.69),
("Values", "copy + destroy citm", 1.11),
("Values", "== citm", 1.04),
]
def overview():
W, L, R = 560, 190, 520
hi = max(v for _, _, v in OVERVIEW)
hi = math.ceil(hi + 0.5)
X = lambda v: L + v / hi * (R - L)
pitch, bh, top = 24, 15, 34
b, desc = [], []
y = top
group = None
rows = []
for g, label, v in OVERVIEW:
if g != group:
if group is not None:
y += 10
b.append('<text class="nj-charts-panel" x="%g" y="%g">%s</text>' % (8, y + 12, esc(g)))
y += 22
group = g
rows.append((label, v, y))
y += pitch
axis_y = y + 2
for t in range(1, hi + 1):
b.append('<line class="nj-charts-grid" x1="%g" y1="%g" x2="%g" y2="%g"/>' % (X(t), top, X(t), axis_y))
b.append('<text class="nj-charts-tick" x="%g" y="%g">%d%s</text>' % (X(t), axis_y + 16, t, TIMES))
for label, v, yy in rows:
b.append('<text class="nj-charts-rowlabel nj-charts-tick--r" x="%g" y="%g" text-anchor="end">%s</text>' % (L - 8, yy + bh - 3, esc(label)))
b.append('<path class="nj-charts-c1" d="%s"><title>%s: %s</title></path>' % (hbar(X(0), X(v), yy, bh), esc(label), fx(v)))
b.append('<text class="nj-charts-val" x="%g" y="%g">%s</text>' % (X(v) + 5, yy + bh - 3, fx(v)))
desc.append("%s %s" % (label, fx(v).replace(TIMES, "x")))
b.append('<line class="nj-charts-ref" x1="%g" y1="%g" x2="%g" y2="%g"/>' % (X(1), top, X(1), axis_y))
b.append('<line class="nj-charts-zero" x1="%g" y1="%g" x2="%g" y2="%g"/>' % (X(0), top, X(0), axis_y))
b.append('<text class="nj-charts-note" x="%g" y="%g">speedup over 3.12.0 (the line at 1%s is 3.12.0)</text>' % (L, 18, TIMES))
write("perf_blog_overview.svg", W, axis_y + 28, "nj-charts--blog", "nj-blog-overview",
"Speedup of 3.13.0 over 3.12.0 per workload, Apple M1 Max, Apple clang",
"Horizontal bars, longer is faster. " + "; ".join(desc) + ".", b)
# ---------- timeline: one panel per workload ----------
# (column in perf_timeline.csv, panel title, [PR numbers to label])
TIMELINE = [
("parse_citm", "parse() citm_catalog.json", [5234, 5283, 5592, 5809, 5810, 5882]),
("parse_canada", "parse() canada.json", [5234, 5283, 5617, 5738, 5851, 5882]),
("accept_twitter", "accept() twitter.json", [5234, 5283, 5592, 5809, 5810, 5853]),
("parse_twitter_ifstream", "parse() twitter.json, std::ifstream", [5828, 5884]),
("dump_twitter", "dump() twitter.json", [5285, 5738, 5878, 5883]),
("dump_canada", "dump() canada.json", [5285, 5634]),
("from_cbor_twitter", "from_cbor() twitter", [5233, 5501, 5185, 5746]),
("to_cbor_twitter", "to_cbor() twitter", [5328, 5824, 5885]),
]
MONTHS = [("2025-04", "3.12.0"), ("2026-09", "Sep 2026"), ("2026-10", "Oct")]
def timeline():
rows = list(csv.DictReader((HERE / "data" / "perf_timeline.csv").open()))
n = len(rows)
W, H = 340, 252
L, R, T, B = 44, 330, 62, 208
for col, title, labels in TIMELINE:
vals = [float(r[col]) if r[col] else None for r in rows]
base = vals[0]
rel = [base / v if v else None for v in vals] # speedup over 3.12.0
hi = max(x for x in rel if x)
top = 2 ** math.ceil(math.log2(hi * 1.3))
Y = lambda s: B - math.log2(s) / math.log2(top) * (B - T)
X = lambda i: L + i / (n - 1) * (R - L)
b = ['<text class="nj-charts-panel" x="%g" y="18">%s</text>' % (8, esc(title))]
t = 1
while t <= top:
b.append('<line class="nj-charts-grid" x1="%g" y1="%g" x2="%g" y2="%g"/>' % (L, Y(t), R, Y(t)))
b.append('<text class="nj-charts-tick nj-charts-tick--r" x="%g" y="%g">%d%s</text>' % (L - 6, Y(t) + 4, t, TIMES))
t *= 2
# month ticks: first commit of the month
seen = set()
for i, r in enumerate(rows):
m = r["date"][:7]
for key, name in MONTHS:
if m == key and key not in seen:
seen.add(key)
b.append('<line class="nj-charts-axis" x1="%g" y1="%g" x2="%g" y2="%g"/>' % (X(i), B, X(i), B + 4))
b.append('<text class="nj-charts-tick" x="%g" y="%g">%s</text>' % (X(i), B + 17, name))
# a step line: each commit's value holds until the next commit
pts, prev = [], None
for i, s in enumerate(rel):
if s is None:
continue
if prev is not None:
pts.append("%.1f,%.1f" % (X(i), Y(prev)))
pts.append("%.1f,%.1f" % (X(i), Y(s)))
prev = s
b.append('<polyline class="nj-charts-json" points="%s"/>' % " ".join(pts))
# labels for named steps: a dot at the commit and its PR number above it; PRs a few commits apart share a
# label, and a label that would overlap one already placed moves up
groups = []
for pr in labels:
i = next(k for k, r in enumerate(rows) if r["pr"] == str(pr))
if groups and X(i) - X(groups[-1][-1][1]) < 6:
groups[-1].append((pr, i))
else:
groups.append([(pr, i)])
# labels in two rows above the plot, each with a guide down to its dot
placed = []
for g in groups:
i = g[-1][1]
x, y = X(i), Y(rel[i])
for pr, k in g:
b.append('<circle class="nj-charts-json-dot" cx="%.1f" cy="%.1f" r="3.5"><title>#%s: %s</title></circle>'
% (X(k), Y(rel[k]), pr, fx(rel[k])))
text = ", ".join("#%s" % pr for pr, _ in g)
w = 7.2 * len(text)
tx = min(max(x, L + w / 2), R - w / 2)
row = 0
while any(r == row and abs(tx - px) < (w + pw) / 2 + 4 for px, r, pw in placed):
row += 1
placed.append((tx, row, w))
ty = 50 - 13 * row
b.append('<line class="nj-charts-grid" stroke-dasharray="2 2" x1="%.1f" y1="%.1f" x2="%.1f" y2="%.1f"/>' % (x, ty + 4, x, y - 5))
b.append('<text class="nj-charts-note" x="%.1f" y="%.1f" text-anchor="middle">%s</text>' % (tx, ty, text))
b.append('<line class="nj-charts-axis" x1="%g" y1="%g" x2="%g" y2="%g"/>' % (L, B, R, B))
final = rel[-1]
desc = ("%s: speedup over 3.12.0 at each of %d commits, ending at %s. Labeled steps: %s."
% (title, n, fx(final).replace(TIMES, "x"), ", ".join("#%s" % p for p in labels)))
write("perf_blog_timeline_%s.svg" % col, W, H, "nj-charts--timeline", "nj-blog-tl-" + col,
"%s: speedup over 3.12.0 by commit" % title, desc, b)
# ---------- cliffs: 3.12.0 and 3.13.0 times on a log axis ----------
# (operation, 3.12.0 ms, 3.13.0 ms), copied from the table in "Fix the algorithm first"
CLIFFS = [
("diff() 64k numbers vs []", 4102, 9.98),
("diff() 20k objects vs half", 119, 3.85),
("parse() callback, 32k objects", 1334, 11.5),
("< nested 24 deep", 62.6, 0.002),
("< citm, 10x", 274, 3.81),
("flatten() citm, ordered_json", 253, 1.37),
("to_bson() 200 deep, 100x", 19.5, 0.566),
("push_back() 100k, diagnostics", 1514, 4.98),
("at(i) 10k, diagnostics", 43.2, 0.081),
]
def cliffs():
W, L, R = 600, 250, 585
lo, hi = -3, 4 # 1 µs .. 10 s, in log10 ms
X = lambda ms: L + (math.log10(ms) - lo) / (hi - lo) * (R - L)
top, pitch = 40, 34
b, desc = [], []
axis_y = top + pitch * len(CLIFFS) - 10
for e in range(lo, hi + 1):
b.append('<line class="nj-charts-grid" x1="%g" y1="%g" x2="%g" y2="%g"/>' % (X(10 ** e), top - 10, X(10 ** e), axis_y))
lab = {-3: "1 µs", -2: "10 µs", -1: "0.1 ms", 0: "1 ms", 1: "10 ms", 2: "0.1 s", 3: "1 s", 4: "10 s"}[e]
b.append('<text class="nj-charts-tick" x="%g" y="%g">%s</text>' % (X(10 ** e), axis_y + 16, lab))
b.append('<circle class="nj-charts-ojson-dot" cx="%g" cy="14" r="5"/><text class="nj-charts-leg" x="%g" y="18.5">3.12.0</text>' % (L, L + 10))
b.append('<circle class="nj-charts-json-dot" cx="%g" cy="14" r="5"/><text class="nj-charts-leg" x="%g" y="18.5">3.13.0</text>' % (L + 80, L + 90))
for i, (op, old, new) in enumerate(CLIFFS):
y = top + i * pitch + 8
b.append('<text class="nj-charts-rowlabel" x="%g" y="%g" text-anchor="end">%s</text>' % (L - 10, y + 4, esc(op)))
b.append('<line class="nj-charts-axis" x1="%g" y1="%g" x2="%g" y2="%g"/>' % (X(new), y, X(old), y))
b.append('<circle class="nj-charts-ojson-dot" cx="%g" cy="%g" r="5"><title>%s, 3.12.0: %g ms</title></circle>' % (X(old), y, esc(op), old))
b.append('<circle class="nj-charts-json-dot" cx="%g" cy="%g" r="5"><title>%s, 3.13.0: %g ms</title></circle>' % (X(new), y, esc(op), new))
b.append('<text class="nj-charts-factor" x="%g" y="%g">%s</text>' % ((X(old) + X(new)) / 2, y - 7, fx(old / new)))
desc.append("%s: %g ms to %g ms" % (op, old, new))
write("perf_blog_cliffs.svg", W, axis_y + 28, "nj-charts--blog", "nj-blog-cliffs",
"Operations that grew quadratically or worse: time with 3.12.0 and 3.13.0, log scale",
"Dot plot on a logarithmic time axis. " + "; ".join(desc) + ".", b)
# ---------- json_view: parse throughput ----------
# engines and GB/s per file, copied from the table in "Build a different data structure"
VIEW_FILES = ["twitter.json", "citm_catalog.json", "canada.json", "jeopardy.json"]
VIEW_BYTES = [631514, 1727204, 2251051, 55554625]
VIEW_US = [ # (engine, css class, [µs per file]), fresh documents, from the table in "How it compares"
("json_document", "nj-charts-c1", [183, 364, 943, 22681]),
("yyjson", "nj-charts-c2", [194, 478, 1489, 30342]),
("simdjson DOM", "nj-charts-c3", [202, 486, 2097, 26904]),
("sonic-rs (Rust)", "nj-charts-c4", [302, 664, 1907, 30202]),
("sonic-cpp", "nj-charts-c5", [379, 986, 2580, 40804]),
("Boost.JSON", "nj-charts-c6", [868, 1483, 2481, 88925]),
("json::parse", "nj-charts-c1 nj-charts-dim", [1352, 2386, 5915, 163750]),
]
VIEW = [(e, c, [n / (t * 1000) for n, t in zip(VIEW_BYTES, us)]) for e, c, us in VIEW_US] # GB/s
def view():
W, L, R = 580, 142, 545
hi = max(max(v) for _, _, v in VIEW)
hi = math.ceil(hi * 2) / 2
X = lambda v: L + v / hi * (R - L)
bh, gap = 9, 2
top = 64
group_h = len(VIEW) * (bh + gap) + 14
b, desc = [], []
x, ly = 8, 10
for j, (eng, cls, _) in enumerate(VIEW):
w = 18 + 7.4 * len(eng) + 16
if x + w > W:
x, ly = 8, ly + 20
b.append('<rect class="%s" x="%g" y="%g" width="12" height="12" rx="3"/>' % (cls, x, ly))
b.append('<text class="nj-charts-leg" x="%g" y="%g">%s</text>' % (x + 18, ly + 10.5, esc(eng)))
x += w
axis_y = top + group_h * len(VIEW_FILES)
t = 0.5
while t <= hi + 1e-9:
b.append('<line class="nj-charts-grid" x1="%g" y1="%g" x2="%g" y2="%g"/>' % (X(t), top - 4, X(t), axis_y))
b.append('<text class="nj-charts-tick" x="%g" y="%g">%g</text>' % (X(t), axis_y + 16, t))
t += 0.5
b.append('<text class="nj-charts-tick" x="%g" y="%g">GB/s, longer is faster</text>' % ((L + R) / 2, axis_y + 34))
for i, f in enumerate(VIEW_FILES):
y0 = top + i * group_h
b.append('<text class="nj-charts-rowlabel" x="%g" y="%g" text-anchor="end">%s</text>' % (L - 8, y0 + group_h / 2, esc(f)))
for j, (eng, cls, vals) in enumerate(VIEW):
y = y0 + j * (bh + gap)
b.append('<path class="%s" d="%s"><title>%s, %s: %.2f GB/s</title></path>' % (cls, hbar(X(0), X(vals[i]), y, bh), esc(eng), esc(f), vals[i]))
b.append('<text class="nj-charts-val" x="%g" y="%g">%.2f</text>' % (X(vals[i]) + 4, y + bh - 1.5, vals[i]))
desc.append("%s %s %.2f GB/s" % (f, eng, vals[i]))
b.append('<line class="nj-charts-zero" x1="%g" y1="%g" x2="%g" y2="%g"/>' % (X(0), top - 4, X(0), axis_y))
write("perf_blog_view.svg", W, axis_y + 44, "nj-charts--blog", "nj-blog-view",
"Parse throughput of json_document and six other document parsers, fresh documents, Apple M1 Max",
"Grouped horizontal bars in GB/s. " + "; ".join(desc) + ".", b)
if __name__ == "__main__":
swar()
if OVERVIEW:
overview()
if TIMELINE:
timeline()
if CLIFFS:
cliffs()
if VIEW:
view()
Reference in new issue View Git Blame Copy Permalink