Skip to content

simplify the IP benchmark #351

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
lemire merged 5 commits into from
Dec 23, 2025
Merged

simplify the IP benchmark #351

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
5 commits
Select commit Hold shift + click to select a range
62ed60e
simplify the benchmark
lemire Dec 23, 2025
55723db
add a memcpy baseline
lemire Dec 23, 2025
b5ae54c
adding a memcpy benchmark and ensure inlining.
lemire Dec 23, 2025
bfa7bcc
lint
lemire Dec 23, 2025
75d01f0
display the inner count (check)
lemire Dec 23, 2025
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
2 changes: 1 addition & 1 deletion benchmarks/CMakeLists.txt
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -3,7 +3,7 @@ include(FetchContent)
FetchContent_Declare(
counters
GIT_REPOSITORY https://github.com/lemire/counters.git
GIT_TAG v2.0.0
GIT_TAG v2.1.0
)

FetchContent_MakeAvailable(counters)
Expand Down
159 changes: 101 additions & 58 deletions benchmarks/bench_ip.cpp
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -11,22 +11,49 @@

void pretty_print(size_t volume, size_t bytes, std::string name,
counters::event_aggregate agg) {
if (agg.inner_count > 1) {
printf("# (inner count: %d)\n", agg.inner_count);
}
printf("%-40s : ", name.c_str());
printf(" %5.2f GB/s ", bytes / agg.fastest_elapsed_ns());
printf(" %5.1f Ma/s ", volume * 1000.0 / agg.fastest_elapsed_ns());
printf(" %5.2f ns/d ", agg.fastest_elapsed_ns() / volume);
printf(" %5.1f Mip/s ", volume * 1000.0 / agg.fastest_elapsed_ns());
printf(" %5.2f ns/ip ", agg.fastest_elapsed_ns() / volume);
if (counters::event_collector().has_events()) {
printf(" %5.2f GHz ", agg.fastest_cycles() / agg.fastest_elapsed_ns());
printf(" %5.2f c/d ", agg.fastest_cycles() / volume);
printf(" %5.2f i/d ", agg.fastest_instructions() / volume);
printf(" %5.2f c/ip ", agg.fastest_cycles() / volume);
printf(" %5.2f i/ip ", agg.fastest_instructions() / volume);
printf(" %5.2f c/b ", agg.fastest_cycles() / bytes);
printf(" %5.2f i/b ", agg.fastest_instructions() / bytes);
printf(" %5.2f i/c ", agg.fastest_instructions() / agg.fastest_cycles());
}
printf("\n");
}

int parse_u8_fastfloat(const char *&p, const char *pend, uint8_t *out) {
fastfloat_really_inline const char *seek_ip_end(const char *p,
const char *pend) {
const char *current = p;
size_t count = 0;
for (; current != pend; ++current) {
if (*current == '.') {
count++;
if (count == 3) {
++current;
break;
}
}
}
while (current != pend) {
if (*current <= '9' && *current >= '0') {
++current;
} else {
break;
}
}
return current;
}

fastfloat_really_inline int parse_u8_fastfloat(const char *&p, const char *pend,
uint8_t *out) {
if (p == pend)
return 0;
auto r = fast_float::from_chars(p, pend, *out);
Expand All @@ -37,10 +64,11 @@ int parse_u8_fastfloat(const char *&p, const char *pend, uint8_t *out) {
return 0;
}

static inline int parse_u8_fromchars(const char *&p, const char *pend,
uint8_t *out) {
if (p == pend)
fastfloat_really_inline int parse_u8_fromchars(const char *&p, const char *pend,
uint8_t *out) {
if (p == pend) {
return 0;
}
auto r = std::from_chars(p, pend, *out);
if (r.ec == std::errc()) {
p = r.ptr;
Expand All @@ -50,26 +78,35 @@ static inline int parse_u8_fromchars(const char *&p, const char *pend,
}

template <typename Parser>
static inline int parse_ip_line(const char *&p, const char *pend, uint32_t &sum,
Parser parse_uint8) {
uint8_t o = 0;
for (int i = 0; i < 4; ++i) {
if (!parse_uint8(p, pend, &o))
return 0;
sum += o;
if (i != 3) {
if (p == pend || *p != '.')
return 0;
++p;
}
fastfloat_really_inline std::pair<bool, uint32_t>
simple_parse_ip_line(const char *p, const char *pend, Parser parse_uint8) {
uint8_t v1;
if (!parse_uint8(p, pend, &v1)) {
return {false, 0};
}
if (p == pend || *p++ != '.') {
return {false, 0};
}
uint8_t v2;
if (!parse_uint8(p, pend, &v2)) {
return {false, 0};
}
if (p == pend || *p++ != '.') {
return {false, 0};
}
uint8_t v3;
if (!parse_uint8(p, pend, &v3)) {
return {false, 0};
}
if (p == pend || *p++ != '.') {
return {false, 0};
}
// consume optional '\r'
if (p != pend && *p == '\r')
++p;
// expect '\n' or end
if (p != pend && *p == '\n')
++p;
return 1;
uint8_t v4;
if (!parse_uint8(p, pend, &v4)) {
return {false, 0};
}
return {true, (uint32_t(v1) << 24) | (uint32_t(v2) << 16) |
(uint32_t(v3) << 8) | uint32_t(v4)};
}

static std::string make_ip_line(uint8_t a, uint8_t b, uint8_t c, uint8_t d) {
Expand All @@ -87,19 +124,22 @@ static std::string make_ip_line(uint8_t a, uint8_t b, uint8_t c, uint8_t d) {
}

int main() {
constexpr size_t N = 500000;
constexpr size_t N = 15000;
std::mt19937 rng(1234);
std::uniform_int_distribution<int> dist(0, 255);

std::string buf;
buf.reserve(N * 16);
constexpr size_t ip_size = 16;
buf.reserve(N * ip_size);

for (size_t i = 0; i < N; ++i) {
uint8_t a = (uint8_t)dist(rng);
uint8_t b = (uint8_t)dist(rng);
uint8_t c = (uint8_t)dist(rng);
uint8_t d = (uint8_t)dist(rng);
buf += make_ip_line(a, b, c, d);
std::string ip_line = make_ip_line(a, b, c, d);
ip_line.resize(ip_size, ' '); // pad to fixed size
buf.append(ip_line);
}

// sentinel to allow 4-byte loads at end
Expand All @@ -108,40 +148,40 @@ int main() {
const size_t bytes = buf.size() - 4; // exclude sentinel from throughput
const size_t volume = N;

// validate correctness
{
const char *start = buf.data();
const char *end = buf.data() + bytes;
const char *p = start;
const char *pend = end;
uint32_t sum = 0;
for (size_t i = 0; i < N; ++i) {
int ok = parse_ip_line(p, pend, sum, parse_u8_fromchars);
if (!ok) {
std::fprintf(stderr, "fromchars parse failed at line %zu\n", i);
std::abort();
}
p = start;
pend = end;
ok = parse_ip_line(p, pend, sum, parse_u8_fastfloat);
if (!ok) {
std::fprintf(stderr, "fastswar parse failed at line %zu\n", i);
std::abort();
}
}
}
volatile uint32_t sink = 0;
std::string buffer(ip_size * N, ' ');

pretty_print(volume, bytes, "memcpy baseline", counters::bench([&]() {
std::memcpy((char *)buffer.data(), buf.data(), bytes);
}));

uint32_t sink = 0;
pretty_print(volume, bytes, "just_seek_ip_end (no parse)",
counters::bench([&]() {
const char *p = buf.data();
const char *pend = buf.data() + bytes;
uint32_t sum = 0;
int ok = 0;
for (size_t i = 0; i < N; ++i) {
const char *q = seek_ip_end(p, pend);
sum += (uint32_t)(q - p);
p += ip_size;
}
sink += sum;
}));

pretty_print(volume, bytes, "parse_ip_std_fromchars", counters::bench([&]() {
const char *p = buf.data();
const char *pend = buf.data() + bytes;
uint32_t sum = 0;
int ok = 0;
for (size_t i = 0; i < N; ++i) {
ok = parse_ip_line(p, pend, sum, parse_u8_fromchars);
if (!ok)
auto [ok, ip] =
simple_parse_ip_line(p, pend, parse_u8_fromchars);
sum += ip;
if (!ok) {
std::abort();
}
p += ip_size;
}
sink += sum;
}));
Expand All @@ -152,13 +192,16 @@ int main() {
uint32_t sum = 0;
int ok = 0;
for (size_t i = 0; i < N; ++i) {
ok = parse_ip_line(p, pend, sum, parse_u8_fastfloat);
if (!ok)
auto [ok, ip] =
simple_parse_ip_line(p, pend, parse_u8_fastfloat);
sum += ip;
if (!ok) {
std::abort();
}
p += ip_size;
}
sink += sum;
}));

std::printf("sink=%u\n", sink);
return EXIT_SUCCESS;
}