[lttng-dev] background information about LTTng timestamps

[Sébastien Barthélémy]

Hello Mathieu,

I just came over commit aae88c703374f4b1fbb8a5e7e95591bf8ce3e837
"Force 64 bits timestamp"  [1].

I never understood how 27bits overflow detection was supposed to work. However,
when using large headers, the 32bits overflow detection made sense to me:

the 32 MSBs of the previous timestamp are kept in the channel so it can detect
overflow before writing the header.

So I don't understand why this new change is needed. Could you
(briefly) explain it?

Or maybe it is for < 32bits arch?

Regards
-- Sébastien