mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-08-23 17:30:02 +00:00
2abfcd293b
The canonical location for the tracefs filesystem is at /sys/kernel/tracing. But, from Documentation/trace/ftrace.rst: Before 4.1, all ftrace tracing control files were within the debugfs file system, which is typically located at /sys/kernel/debug/tracing. For backward compatibility, when mounting the debugfs file system, the tracefs file system will be automatically mounted at: /sys/kernel/debug/tracing Many parts of Documentation still reference this older debugfs path, so let's update them to avoid confusion. Signed-off-by: Ross Zwisler <zwisler@google.com> Reviewed-by: Steven Rostedt (Google) <rostedt@goodmis.org> Link: https://lore.kernel.org/r/20230125213251.2013791-1-zwisler@google.com Signed-off-by: Jonathan Corbet <corbet@lwn.net>
40 lines
771 B
ReStructuredText
40 lines
771 B
ReStructuredText
================
|
|
MSR Trace Events
|
|
================
|
|
|
|
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.
|
|
|