Hi all, 
Info:
I´m using Linux Lite 6.2 ( as some of you might now already).
Recently I noticed a red “failed” entry during the log-in messages which were running across the screen during boot.
It was too fast gone however to exactly determine what it was, so I took a look at the boot messages afterwards.
Booting the system and logging in worked just fine. No problems there.
When looking at the boot logs with the help of lnav I found this message however:
kernel: [ 0.141658] tsc: Marking TSC unstable due to check_tsc_sync_source failed.
This must have been the one I noticed. 
I didn´t have the knowledge to interpret it and to make any sense of it. As I said, there were no problems regarding boot. And there were no blems when running the system afterwards.
So I did a bit of research on the matter and found out the message is related to the Time Stamp Counter (TSC) during the Linux kernel’s boot process.
TSC seems to be a feature in modern processors that counts the number of clock cycles since the system started.
It´s often used for timestamping events and measuring time intervals.
The kernel performs a check during boot to ensure that the TSC is reliable and can be used as a stable timekeeping source.
The message apparently indicates that the check (check_tsc_sync_source) for the stability of the TSC failed, leading to the TSC being marked as unstable. 
Despite this message my system was booting fine, as I said earlier.
I then checked all the syslogs available, the oldest one being syslog.4.gz.
Like so: zcat /var/log/syslog.4.gz | grep -i 'tsc unstable
It turned out the same message was there every day during the past month. I couldn´t go back further into the past but I´m sure it had been this way before as well. It was just now (by coincidence) that I noticed it.
Can anyone tell me more about it? I mean: should I worry or just ignore the message 
Thanks a lot in advance for your help.
Many greetings from Rosika 
