Measures the time it takes to decompress the linux kernel

measure-linux-decompress.cpp

#include <chrono>
#include <stdio.h>

namespace {
void wait_for_needle(char const* needle) {
    char const* suffix = needle;
    while (*suffix != '\0') {
        auto const c = getc(stdin);
        if (c == *suffix) {
            ++suffix;
        } else {
            suffix = needle;
        }
    }
}
void wait_for_start() {
    wait_for_needle("Decompressing Linux...");
}
void wait_for_end() {
    wait_for_needle("Parsing ELF");
}
}

int main() {
    wait_for_start();
    auto begin = std::chrono::steady_clock::now();
    wait_for_end();
    auto end = std::chrono::steady_clock::now();
    auto dur = std::chrono::duration_cast<std::chrono::milliseconds>(end - begin);
    fprintf(stdout, "time = %u ms\n", (unsigned)(dur.count()));
    return 0;
}