Revision e64dd5ef

b/docs/tracing.txt
175 175 
The "simple" backend currently does not capture string arguments, it simply
176 176 
records the char* pointer value instead of the string that is pointed to.
177 177 

  		





  
  178
  
    
=== Ftrace ===


  		





  
  179
  
    

  		





  
  180
  
    
The "ftrace" backend writes trace data to ftrace marker. This effectively


  		





  
  181
  
    
sends trace events to ftrace ring buffer, and you can compare qemu trace


  		





  
  182
  
    
data and kernel(especially kvm.ko when using KVM) trace data.


  		





  
  183
  
    

  		





  
  184
  
    
if you use KVM, enable kvm events in ftrace:


  		





  
  185
  
    

  		





  
  186
  
    
   # echo 1 > /sys/kernel/debug/tracing/events/kvm/enable


  		





  
  187
  
    

  		





  
  188
  
    
After running qemu by root user, you can get the trace:


  		





  
  189
  
    

  		





  
  190
  
    
   # cat /sys/kernel/debug/tracing/trace


  		





  
  191
  
    

  		





  
  192
  
    
Restriction: "ftrace" backend is restricted to Linux only.


  		





  
  193
  
    

  		





  178
  194
  
    
==== Monitor commands ====


  		





  179
  195
  
    

  		





  180
  196
  
    
* trace-file on|off|flush|set <path>


  		












Also available in:
  Unified diff