This post is more than 5 years old
13 Posts
0
107704
PowerEdge R910 - RHEL 6.4 - Clocksource problem
Dear All,
I am running RHEL 6.4 in a PowerEdge R910.
When I do:
# dmesg | grep -i clock
I am getting a lot of messages with this text:
"Clocksource tsc unstable (delta = 580433372 ns). Enable clocksource failover by adding clocksource_failover kernel parameter."
I have been looking for a solution. Concretely, Red Hat propose the following:
https://access.redhat.com/site/solutions/434883
That is, changing the clocksource. However it did not solve the problem.
Actually, when I do:
cat /sys/devices/system/clocksource/clocksource0/available_clocksource
my options are: tsc jiffies
so when I change the clocksource to jiffies, the problem remains.
I must say that the kernel writes those messages when the server is powered on/rebooted. Then, after a few minutes it stops.
Have any of you had this problem? Did you find any solution? Is it a symptom for a hardware problem?
Many thanks in advance for your help.
Best regards,
Sebastian.
sebastian.luna.
13 Posts
0
September 20th, 2013 03:00
Dear Josh,
I think I have found the solution to this problem, thanks to the post here:
http://superuser.com/questions/393969/what-does-clocksource-tsc-unstable-mean
This server was booting a kernel (2.6.32-358.18.1.el6.x86_64) with the options "acpi=off noapic". The solution was to remove those options.
After rebooting the server I have noticed two changes. First, the output of the available clocksources:
cat /sys/devices/system/clocksource/clocksource0/available_clocksource
was:
tsc jiffies
and now is:
tsc hpet acpi_pm
On the other hand, the output for "dmesg | grep -i clock"
was:
Clocksource tsc unstable (delta = 568832927 ns). Enable clocksource failover by adding clocksource_failover kernel parameter.
and that message was displayed twice per second approximately. Now is:
hpet clockevent registered
Switching to clocksource hpet
rtc_cmos 00:04: setting system clock to 2013-09-20 08:46:50 UTC (1379666810)
Refined TSC clocksource calibration: 2260.999 MHz.
Switching to clocksource tsc
which seems to be the correct output.
I hope this is useful for others too!
Best regards,
Sebastian.
DELL-Josh Cr
Moderator
Moderator
•
8.7K Posts
0
September 5th, 2013 08:00
The error that you are getting is the system time being unstable. If it is reporting the correct time it is probably not anything to worry about. You can try turning off the processor power saving features in the BIOS as it is possible that the changing of clockspeeds is causing the error. In the BIOS under processor information turn off c-states and C1E. You may also want to update the BIOS to the latest version. http://downloads.dell.com/FOLDER00983013M/8/R910_BIOS_CJF6T_LN32_2.8.2.BIN
Checking to make sure the time in the BIOS is correct as well might help.
sebastian.luna.
13 Posts
0
September 5th, 2013 10:00
Dear Josh,
Many thanks for your help.
I did check that the BIOS firmware is up to date and also the c and c1e states are disabled. However, the problem remains.
Fortunately the system's time is correct so I am happy to know that it is not a hardware related problem.
Best regards,
Sebastian.