iodide-project/iodide

Can I ask a question about Firefox vs. Chrome? I wrote (as a rough benchmark) this program that calculates pi using the formula pi/4 = 1 - 1/3 + 1/5 - 1/7 ... by looping 10 million times, and tells you how much it took:

#include <sys/time.h>
#include <stdio.h>
#include <stdlib.h>

int main (void) {
    double pi = 4;
    double denom = 3;
    double sign = -1;
    struct timeval tv1, tv2;
    gettimeofday(&tv1, NULL);
    while (denom < 1e8) {
        pi = pi + sign * 4.0 / denom;
        denom += 2.0;
        sign = sign * -1.0;
    }
    gettimeofday(&tv2, NULL);
    time_t secs = tv2.tv_sec - tv1.tv_sec;
    suseconds_t usecs = tv2.tv_usec - tv1.tv_usec;
    printf("%f %f\n", pi, secs * 1000 + usecs / 1000.0);
    exit(0);
}

On my computer, I compile it with gcc and I execute it, and it takes about 300 ms. I compile it with emcc and run it with node, again it takes about 300 ms (I'm impressed). I run it with Chrome, it takes about 300 ms. I run it with Firefox, it takes about 1000 ms, which is about as much as a JS version of the same program takes.

Am I doing something wrong?

BTW, the WASM engine is part of the JS engine? The answer to "which WASM engine does Firefox have" is SpiderMonkey?