Continuing from the preceding section, on the command line, we can get a (very!) detailed report of what occurred within the kernel when the ps process ran; use the trace-cmd report command to see this. We also pass along the -l option switch: it displays the report in what is referred to as Ftrace's latency format, revealing many useful details; the -i switch of course specifies the input file to use:
trace-cmd report -i ./trace_ps.dat -l > report_tc_ps.txt
Now it gets very interesting! We show a few partial screenshots of the (huge) output file that we opened with vim(1); first we have the following:
Figure 11.2 – A partial screenshot showing the output of the trace-cmd report
Look at Figure 11.2; the call to the kernel API, schedule(), is deliberately highlighted and in bold font (Figure 11.2, on line 785303!). In order to interpret everything...