tblocklinux
New Member
Hello all,
I have a problem that I have been working on for some time now, but unfortunately could not solve.
I am working on a NUC6CAYH running Ubuntu 20.04.2 LTS. However, I have made the kernel real-time capable with the Preempt RT patch.
uname -r -v -p -o deliver:
4.9.251-rt166 #1 SMP PREEMPT RT Sun Feb 7 16:35:16 CET 2021 x86_64 GNU/Linux
Here I am trying to find out via: "cyclictest --mlockall --smp --priority=98 --Interval=1000 --distance=0 --smi" if my latencies in a concurrently running program are coming from the System Management Interrupts.
So far so good I think...
Now to my problem. When I run the cyclictest as root user (via sudo su) it only works if I omit the --smi option. If I add the option and run the test, the input returns the following result:
# /dev/cpu_dma_latency set to 0us
WARN: /dev/cpu/0/msr open failed, try chown or chmod +r /dev/cpu/*/msr, or run as root
FATAL: Could not open MSR interface, errno: 2
WARN: /dev/cpu/1/msr open failed, try chown or chmod +r /dev/cpu/*/msr, or run as root
FATAL: Could not open MSR interface, errno: 2
Also, I already tried to create the directories myself for all four cores manually using the following commands: (found in other forum)
mkdir -p /dev/cpu/0
mknod -m 444 /dev/cpu/0/msr c 202 0
mknod -m 444 /dev/cpu/0/cpuid c 203 0
chmod a+rwx /dev/cpu/0/msr
And then run the test again. Unfortunately, this did not work either. This returned:
# /dev/cpu_dma_latency set to 0us
WARN: /dev/cpu/0/msr open failed, try chown or chmod +r /dev/cpu/*/msr, or run as root
FATAL: Could not open MSR interface, errno: 6
Maybe someone can help me here.
Would help me very much
I have a problem that I have been working on for some time now, but unfortunately could not solve.
I am working on a NUC6CAYH running Ubuntu 20.04.2 LTS. However, I have made the kernel real-time capable with the Preempt RT patch.
uname -r -v -p -o deliver:
4.9.251-rt166 #1 SMP PREEMPT RT Sun Feb 7 16:35:16 CET 2021 x86_64 GNU/Linux
Here I am trying to find out via: "cyclictest --mlockall --smp --priority=98 --Interval=1000 --distance=0 --smi" if my latencies in a concurrently running program are coming from the System Management Interrupts.
So far so good I think...
Now to my problem. When I run the cyclictest as root user (via sudo su) it only works if I omit the --smi option. If I add the option and run the test, the input returns the following result:
# /dev/cpu_dma_latency set to 0us
WARN: /dev/cpu/0/msr open failed, try chown or chmod +r /dev/cpu/*/msr, or run as root
FATAL: Could not open MSR interface, errno: 2
WARN: /dev/cpu/1/msr open failed, try chown or chmod +r /dev/cpu/*/msr, or run as root
FATAL: Could not open MSR interface, errno: 2
Also, I already tried to create the directories myself for all four cores manually using the following commands: (found in other forum)
mkdir -p /dev/cpu/0
mknod -m 444 /dev/cpu/0/msr c 202 0
mknod -m 444 /dev/cpu/0/cpuid c 203 0
chmod a+rwx /dev/cpu/0/msr
And then run the test again. Unfortunately, this did not work either. This returned:
# /dev/cpu_dma_latency set to 0us
WARN: /dev/cpu/0/msr open failed, try chown or chmod +r /dev/cpu/*/msr, or run as root
FATAL: Could not open MSR interface, errno: 6
Maybe someone can help me here.
Would help me very much