On Sat, 2 Nov 2019 12:33:58 -0700
Michael Forney <mfor...@mforney.org> wrote:
> I've never used vmstat before, but this looks pretty good overall and
> seems to work well.
>
> On 2019-10-05, Mattias Andrée <maand...@kth.se> wrote:
> > + goto beginning;
> > + for (; argc && (argc < 2 || i < count); i++) {
>
> Why not just set count = 1 when argc < 2?
Because that would stop the loop after 1 iteration.
If argc == 1, the loop should be infinite.
>
> > + clock_nanosleep(CLOCK_MONOTONIC, 0, &delay, NULL);
> > + beginning:
> > + load_vm(&vm[i & 1]);
> > + print_vm(&vm[i & 1], &vm[~i & 1], active_mem, timestamp,
> > one_header ? !i
> > : (i % 50 == 0));
> > + }
>
> I think it might be a bit clearer to re-arrange the loop body to avoid
> the labels and goto.
>
> Something like
>
> count = argc == 2 ? atoll(argv[1]) : 1;
> for (;;) {
> load_vm(&vm[i & 1]);
> print_vm(&vm[i & 1], &vm[~i & 1], active_mem, timestamp,
> one_header
> ? !i : (i % 50 == 0));
> if (++i == count)
> break;
> clock_nanosleep(CLOCK_MONOTONIC, 0, &delay, NULL);
> }
>
This does not work as excepted if argc == 1,
it would just run it once rather than forever.
An alternative that would work is:
for (;;) {
load_vm(&vm[i & 1]);
print_vm(&vm[i & 1], &vm[~i & 1], active_mem, timestamp,
one_header ? !i : (i % 50 == 0));
i++;
if (!argc || (argc == 2 && i == count))
break;
clock_nanosleep(CLOCK_MONOTONIC, 0, &delay, NULL);
}
or (I prefer this one less):
load_vm(&vm[i & 1]);
print_vm(&vm[i & 1], &vm[~i & 1], active_mem, timestamp, one_header ?
!i : (i % 50 == 0));
for (i++; argc && (argc < 2 || i < count); i++) {
clock_nanosleep(CLOCK_MONOTONIC, 0, &delay, NULL);
load_vm(&vm[i & 1]);
print_vm(&vm[i & 1], &vm[~i & 1], active_mem, timestamp,
one_header ? !i : (i % 50 == 0));
}
(or this `argc &&` broken out as an if-statement)
I prefer the original version.
