3 kprof \- kernel profiling
14 device provides simple profiling
15 data for the operating system kernel. The data accumulates by
16 recording the program counter of the kernel at each `tick' of the
21 holds the accumulated counts as 4-byte integers in big-endian
23 The size of the file depends on the size of kernel text.
25 holds the total number of clock ticks during profiling;
26 the second the number of ticks that occurred while the kernel
27 was running. The rest each hold the number of ticks
28 the kernel program counter was within the
29 corresponding 8-byte range of kernel text, starting from the base
41 terminates it. The message
43 restarts profiling after zeroing the array of counts.
49 formats the data for presentation.
53 script runs a test program while profiling the kernel
54 and reports the results.
58 echo start > /dev/kpctl
60 echo stop > /dev/kpctl
61 kprof /386/9pcdisk /dev/kpdata
64 .B /sys/src/9/port/devkprof.c