[systemd-devel] Antw: [EXT] Re: --Reboot-- lines in journal

[Ulrich Windl]

>>> Simon McVittie <smcv at collabora.com> schrieb am 14.05.2020 um 19:16 in
Nachricht
<17311_1589476591_5EBD7CEF_17311_19_1_20200514171619.GA1563955 at horizon>:
> On Thu, 14 May 2020 at 16:12:49 +0300, Mantas Mikulėnas wrote:
>> The "--Reboot--" line is simply shown every time the _BOOT_ID field
changes
>> between two entries -- even if it changes to a previously seen boot ID 
> (which
>> shouldn't happen normally, but *might* be caused by lack of a RTC?).
> 
> The Raspberry Pi doesn't have a real-time clock, so if the journal
> is sorting log entries by their claimed timestamp rather than by the
> order in which they were actually written, it's entirely possible that
> different boots will get interleaved.
> 
> In a traditional syslogd-style log file where entries are written in
> order, you'd see the wallclock time jump backwards at each reboot,
> then jump forwards again when NTP/etc. resynchronizes.

It's a kernel issue, and I don't know: Does the paspbery have a TSC (cycle
counter), and does the BIOS/bootloader produce variable TSC values when the
kernel starts? For an old Pentium my guess would be yes, but I don't know for
such tiny systems...
I'm assuming the TSC influences the initial value of the random pool; if not,
it might be an idea to do so...

> 
>     smcv
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