time_to_string
static char *time_to_string(u64 duration);
time_to_string(end - start));
cpu, time_to_string(end - start));
text = time_to_string(end-start);
fprintf(svgfile, "<title>#%d waiting %s</title>\n", cpu, time_to_string(end - start));
fprintf(svgfile, "<title>%d %s running %s</title>\n", pid, name, time_to_string(end - start));