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| author | Ahmad Fatoum <a.fatoum@pengutronix.de> | 2022-11-02 09:50:17 +0100 |
|---|---|---|
| committer | Sascha Hauer <s.hauer@pengutronix.de> | 2022-11-04 09:54:23 +0100 |
| commit | 40d31b8e45421ed1fb6906a9fe2fca1d75f6b6ef (patch) | |
| tree | f14158a70252ecfa15ba2431b058b63ee253c8f4 /commands | |
| parent | d4204476ccf8318abacd7996a48e2fa0d87fe2d4 (diff) | |
| download | barebox-40d31b8e45421ed1fb6906a9fe2fca1d75f6b6ef.tar.gz | |
commands: uptime: add note about caveats
Normally timer overrun is not that much of a problem, because there
where it matters, we usually have an is_timeout() in the loop that reads
the timer often enough. This doesn't necessarily hold for the new uptime
command and basically anything can happen between subsequent calls and
if get_time_ns() is not called often enough during that time, we end up
with an inaccurate uptime. Mention this in the extended help text.
Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
Link: https://lore.barebox.org/20221102085017.1941580-1-a.fatoum@pengutronix.de
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Diffstat (limited to 'commands')
| -rw-r--r-- | commands/uptime.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/commands/uptime.c b/commands/uptime.c index a9a8c650b6..d67538631c 100644 --- a/commands/uptime.c +++ b/commands/uptime.c @@ -66,6 +66,9 @@ static int do_uptime(int argc, char *argv[]) BAREBOX_CMD_HELP_START(uptime) BAREBOX_CMD_HELP_TEXT("This command formats the number of elapsed nanoseconds") BAREBOX_CMD_HELP_TEXT("as measured with the current clocksource") +BAREBOX_CMD_HELP_TEXT("Note: Timekeeping is co-operative. If long running code does") +BAREBOX_CMD_HELP_TEXT("not use delay/is_timeout/get_time_ns/getchar functions") +BAREBOX_CMD_HELP_TEXT("timer may overrun resulting in incorrect results") BAREBOX_CMD_HELP_TEXT("Options:") BAREBOX_CMD_HELP_OPT ("-n", "output elapsed time in nanoseconds") BAREBOX_CMD_HELP_END |