MSR Trace EventsΒΆ

The x86 kernel supports tracing most MSR (Model Specific Register) accesses. To see the definition of the MSRs on Intel systems please see the SDM at https://www.intel.com/sdm (Volume 3)

Available trace points:

/sys/kernel/tracing/events/msr/

Trace MSR reads:

read_msr

  • msr: MSR number

  • val: Value written

  • failed: 1 if the access failed, otherwise 0

Trace MSR writes:

write_msr

  • msr: MSR number

  • val: Value written

  • failed: 1 if the access failed, otherwise 0

Trace RDPMC in kernel:

rdpmc

The trace data can be post processed with the postprocess/decode_msr.py script:

cat /sys/kernel/tracing/trace | decode_msr.py /usr/src/linux/include/asm/msr-index.h

to add symbolic MSR names.