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Kernel Profiling
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KPROF(3) Library Functions Manual KPROF(3) NAME
kprof - kernel profiling SYNOPSIS
bind -a #T /dev /dev/kpctl /dev/kpdata DESCRIPTION
The kprof device provides simple profiling data for the operating system kernel. The data accumulates by recording the program counter of the kernel at each `tick' of the system clock. The file kpdata holds the accumulated counts as 4-byte integers in big-endian byte order. The size of the file depends on the size of ker- nel text. The first count holds the total number of clock ticks during profiling; the second the number of ticks that occurred while the kernel was running. The rest each hold the number of ticks the kernel program counter was within the corresponding 8-byte range of kernel text, starting from the base of kernel text. The file kpctl controls profiling. Writing the string start to kpctl begins profiling; stop terminates it. The message startclr restarts profiling after zeroing the array of counts. The program kprof (see prof(1)) formats the data for presentation. EXAMPLE
The following rc(1) script runs a test program while profiling the kernel and reports the results. bind -a '#T' /dev echo start > /dev/kpctl runtest echo stop > /dev/kpctl kprof /mips/9power /dev/kpdata SOURCE
/sys/src/9/port/devkprof.c SEE ALSO
prof(1) KPROF(3)
Kernel Profiling