PROF(1)                                                   PROF(1)

     NAME
          prof, tprof, kprof - display profiling data

     SYNOPSIS
          prof [ -dr ] [ program ] [ profile ]

          tprof pid

          kprof kernel kpdata

     DESCRIPTION
          Prof interprets files produced automatically by programs
          loaded using the -p option of 8l(1) or other loader.  The
          symbol table in the named program file (`2.out' etc.,
          according to $objtype, by default) is read and correlated
          with the profile file (`prof.out' by default).  For each
          symbol, the percentage of time (in seconds) spent executing
          between that symbol and the next is printed (in decreasing
          order), together with the time spent there and the number of
          times that routine was called.

          Under option -d, prof prints the dynamic call graph of the
          target program, annotating the calls with the time spent in
          each routine and those it calls, recursively.  The output is
          indented two spaces for each call, and is formatted as

               symbol:time/ncall

          where symbol is the entry point of the call, time is in mil-
          liseconds, and ncall is the number of times that entry point
          was called at that point in the call graph.  If ncall is
          one, the /ncall is elided.  Normally recursive calls are
          compressed to keep the output brief; option -r prints the
          full call graph.

          The size of the buffer in program used to hold the profiling
          data, by default 2000 entries, may be controlled by setting
          the environment variable profsize before running program. If
          the buffer fills, subsequent function calls may not be
          recorded.

          The profiling code provided by the linker initializes itself
          to profile the current pid, producing a file called
          prof.pid. If a process forks, only the parent will continue
          to be profiled.  Forked children can cause themselves to be
          profile by calling

               prof(fn, arg, entries, what)

          which causes the function fn(arg) to be profiled.  When fn

     PROF(1)                                                   PROF(1)

          returns prof.pid is produced for the current process pid.

          The environment variable proftype can be set to one of user,
          kernel, elapsed, or sample, to profile time measured spent
          in user mode, time spent in user+kernel mode, or elapsed
          time, using the cycle counter, or the time in user mode
          using the kernel's HZ clock.  The cycle counter is currently
          only available on modern PCs and on the PowerPC.  Default
          profiling measures user time, using the cycle counter if it
          is available.

          Tprof is similar to prof, but is intended for profiling mul-
          tiprocess programs.  It uses the /proc/pid/profile file to
          collect instruction frequency counts for the text image
          associated with the process, for all processes that share
          that text.  It must be run while the program is still
          active, since the data is stored with the running program.
          To enable tprof profiling for a given process,

               echo profile > /proc/pid/ctl

          and then, after the program has run for a while, execute

               tprof pid

          Since the data collected for tprof is based on interrupt-
          time sampling of the program counter, tprof has no -d or -r
          options.

          Kprof is similar to prof, but presents the data accumulated
          by the kernel profiling device, kprof(3).  The symbol table
          file, that of the operating system kernel, and the data
          file, typically /dev/kpdata, must be provided.  Kprof has no
          options and cannot present dynamic data.

     SOURCE
          /sys/src/cmd/prof.c
          /sys/src/cmd/kprof.c

     SEE ALSO
          8l(1), exec(2), kprof(3)