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Annotation of lucent/sys/man/3/kprof, revision 1.1.1.1

1.1       root        1: .TH KPROF 3 
                      2: .SH NAME
                      3: kprof \- kernel profiling
                      4: .SH SYNOPSIS
                      5: .nf
                      6: .B bind -a #T /dev
                      7: .sp
                      8: .B /dev/kpctl
                      9: .B /dev/kpdata
                     10: .fi
                     11: .SH DESCRIPTION
                     12: The
                     13: .I kprof
                     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
                     17: system clock.
                     18: .PP
                     19: The file
                     20: .B kpdata
                     21: holds the accumulated counts as 4-byte integers in big-endian
                     22: byte order.
                     23: The size of the file depends on the size of kernel text.
                     24: The first count
                     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
                     30: of kernel text.
                     31: .PP
                     32: The file
                     33: .B kpctl
                     34: controls profiling.
                     35: Writing the string
                     36: .B start
                     37: to
                     38: .B kpctl
                     39: begins profiling;
                     40: .B stop
                     41: terminates it.  The message
                     42: .B startclr
                     43: restarts profiling after zeroing the array of counts.
                     44: .PP
                     45: The program
                     46: .I kprof
                     47: (see
                     48: .IR prof (1))
                     49: formats the data for presentation.
                     50: .SH EXAMPLE
                     51: The following
                     52: .IR rc (1)
                     53: script runs a test program while profiling the kernel
                     54: and reports the results.
                     55: .sp
                     56: .EX
                     57:        bind -a '#T' /dev
                     58:        echo start > /dev/kpctl
                     59:        runtest
                     60:        echo stop > /dev/kpctl
                     61:        kprof /mips/9power /dev/kpdata
                     62: .EE
                     63: .SH SOURCE
                     64: .B /sys/src/9/port/devkprof.c
                     65: .SH SEE ALSO
                     66: .IR prof (1)

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