Function showLatencyDistSamples

src/redis-cli.c:6024–6043

Helper function for latencyDistMode(). Performs the spectrum visualization * of the collected samples targeting an xterm 256 terminal. * * Takes an array of distsamples structures, ordered from smaller to bigger * 'max' value. Last sample max must be 0, to mean that it olds all the * samples greater than the previous one, and is also the stop sentinel. * * "tot' is the total number of sampl

 *
 * As a side effect the function sets all the buckets count to 0. */
void showLatencyDistSamples(struct distsamples *samples, long long tot) {
    int j;

     /* We convert samples into an index inside the palette
     * proportional to the percentage a given bucket represents.
     * This way intensity of the different parts of the spectrum
     * don't change relative to the number of requests, which avoids to
     * pollute the visualization with non-latency related info. */
    printf("\033[38;5;0m"); /* Set foreground color to black. */
    for (j = 0; ; j++) {
        int coloridx =
            ceil((double) samples[j].count / tot * (spectrum_palette_size-1));
        int color = spectrum_palette[coloridx];
        printf("\033[48;5;%dm%c", (int)color, samples[j].character);
        samples[j].count = 0;
        if (samples[j].max == 0) break; /* Last sample. */
    }
    printf("\033[0m\n");
    fflush(stdout);
}

/* Show the legend: different buckets values and colors meaning, so
 * that the spectrum is more easily readable. */