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Running Transmission causes system clock to be fast (Ubuntu)

Posted: Sun Jan 01, 2012 9:07 pm
by Ranko
I'm running Ubuntu 10.04.3, and Transmission 1.93 (10621) (The latest version in the repository for this version of Ubuntu) The system is an Asus EeePC 701SD, 2GB of RAM, with two external drives in software RAID.

When NOT running Transmission, the system keeps perfect time, +/- 0.2 secs per 24 hours, compared to my watch, cell phone, and another laptop.

When Transmission is running, however, the clock gains about 2.5 hours per 24.

I didn't see this issue after searching, so I'm wondering if it's a known bug that got fixed, or what's the deal.

Re: Running Transmission causes system clock to be fast (Ubu

Posted: Sun Jan 01, 2012 9:22 pm
by x190

Re: Running Transmission causes system clock to be fast (Ubu

Posted: Mon Jan 02, 2012 1:13 am
by Ranko
I neglected to mention the following: When Transmission is running, automatic NTP update fails. (whether it works or not regularly I can't honestly say, with or without it keeps precision time when Transmission is NOT running.) I can manually force an "ntpdate" from the command line, but I don't want to schedule a cron job as a band-aid.

Re: Running Transmission causes system clock to be fast (Ubu

Posted: Mon Jan 02, 2012 7:35 am
by x190
When Transmission is running, automatic NTP update fails.
Why? That is not controlled by Transmission. If your router was so overloaded that updates couldn't get through then you would likely see browsing issues as well.

Shouldn't you check that the relevant ntp file(s) are in place and that firewalls are not blocking updates?

http://www.pool.ntp.org/en/use.html
it keeps precision time when Transmission is NOT running.
Transmission does use a lot of CPU time, so maybe timekeeping is affected. But then isn't that why we have ntp?

Re: Running Transmission causes system clock to be fast (Ubu

Posted: Mon Jan 02, 2012 11:07 am
by Ranko
x190 wrote:
When Transmission is running, automatic NTP update fails.
Why? That is not controlled by Transmission. If your router was so overloaded that updates couldn't get through then you would likely see browsing issues as well.
No browsing issues, I've got the bandwidth limited below 50% rated speed for that reason, and manual NTP updates via the command line work fine.
x190 wrote:Shouldn't you check that the relevant ntp file(s) are in place and that firewalls are not blocking updates?
No firewall to block updates, and NTP is handled by the package manager... A reinstall changes nothing. I also can't find any relevant hits in the syslog regarding NTP.
x190 wrote:Transmission does use a lot of CPU time, so maybe timekeeping is affected. But then isn't that why we have ntp?
I can't think of any logical reason why CPU consumption would matter to timekeeping. But that's a non-issue anyway, as Transmission doesn't use that much to begin with, (up to about 10% while running normally, or up to 40% when re-checking torrents), plus, extremely high CPU-load—such as SSH-tunneled FTP transfers over LAN—max the processor out, sometimes for hours at a time. If Transmission is not running during this time, the clock still keeps perfect time.