www:~> cd /usr/local/lib/php
www:/usr/local/lib/php> ln -s extensions/no-debug-non-zts-20020429/apd.so apd.so
Then in your php.ini file:

zend_extension = "/usr/local/lib/php/apd.so"
apd.dumpdir = /tmp
It isn't completely transparent. You need to tell the profiler when to start profiling. At the top of a script you want to profile, add this call:

<?php
apd_set_pprof_trace
();
?>
The use the command-line tool called pprofp:

wwww: ~> pprofp
pprofp <flags> <trace file>
    Sort options
    -a          Sort by alphabetic names of subroutines.
    -l          Sort by number of calls to subroutines
    -m          Sort by memory used in a function call.
    -r          Sort by real time spent in subroutines.
    -R          Sort by real time spent in subroutines (inclusive of child calls).
    -s          Sort by system time spent in subroutines.
    -S          Sort by system time spent in subroutines (inclusive of child calls).
    -u          Sort by user time spent in subroutines.
    -U          Sort by user time spent in subroutines (inclusive of child calls).
    -v          Sort by average amount of time spent in subroutines.
    -z          Sort by user+system time spent in subroutines. (default)

    Display options
    -c          Display Real time elapsed alongside call tree.
    -i          Suppress reporting for php builtin functions
    -O <cnt>    Specifies maximum number of subroutines to display. (default 15)
    -t          Display compressed call tree.
    -T          Display uncompressed call tree.
% ls -latr /tmp/pprofp.*
-rw-r--r--    1 nobody   nobody      16692 Dec  3 01:19 /tmp/pprof.04545

% pprofp -z /tmp/pprof.04545
Trace for /home/rasmus/phpweb/bm.php
Total Elapsed Time =    0.01
Total System Time  =    0.00
Total User Time    =    0.01

         Real         User        System             secs/    cumm
%Time (excl/cumm)  (excl/cumm)  (excl/cumm) Calls    call    s/call  Memory Usage Name
--------------------------------------------------------------------------------------
100.0  0.01  0.01   0.01  0.01   0.00  0.00     2   0.0050    0.0050         3488 include
  0.0  0.00  0.00   0.00  0.00   0.00  0.00     1   0.0000    0.0000           48 c
  0.0  0.00  0.00   0.00  0.00   0.00  0.00    21   0.0000    0.0000         1168 b
  0.0  0.00  0.00   0.00  0.00   0.00  0.00     1   0.0000    0.0000           56 a
  0.0  0.00  0.00   0.00  0.00   0.00  0.00     1   0.0000    0.0000            0 main
  0.0  0.00  0.00   0.00  0.00   0.00  0.00     1   0.0000    0.0000         1080 range
Trace for /home/rasmus/phpweb/index.php
Total Elapsed Time =    0.69
Total System Time  =    0.01
Total User Time    =    0.08

         Real         User        System             secs/    cumm
%Time (excl/cumm)  (excl/cumm)  (excl/cumm) Calls    call    s/call  Memory Usage Name
--------------------------------------------------------------------------------------
 33.3  0.11  0.13   0.02  0.03   0.01  0.01     7   0.0043    0.0057       298336 require_once
 22.2  0.02  0.02   0.02  0.02   0.00  0.00   183   0.0001    0.0001       -33944 feof
 11.1  0.01  0.01   0.01  0.01   0.00  0.00     3   0.0033    0.0033       -14808 define
 11.1  0.04  0.04   0.01  0.01   0.00  0.00   182   0.0001    0.0001       112040 fgetcsv
 11.1  0.25  0.25   0.01  0.01   0.00  0.00     6   0.0017    0.0017         3768 getimagesize
 11.1  0.01  0.01   0.01  0.01   0.00  0.00    55   0.0002    0.0002         2568 sprintf
  0.0  0.00  0.00   0.00  0.00   0.00  0.00     7   0.0000    0.0000         -136 printf
  0.0  0.00  0.00   0.00  0.00   0.00  0.00     1   0.0000    0.0000          136 htmlspecialchars
  0.0  0.00  0.00   0.00  0.00   0.00  0.00     1   0.0000    0.0000          -16 mirror_provider_url
  0.0  0.00  0.00   0.00  0.00   0.00  0.00     7   0.0000    0.0000          112 spacer
  0.0  0.00  0.00   0.00  0.00   0.00  0.00    10   0.0000    0.0000         -552 delim
  0.0  0.00  0.00   0.00  0.00   0.00  0.00     1   0.0000    0.0000          112 mirror_provider
  0.0  0.00  0.00   0.00  0.00   0.00  0.00    20   0.0000    0.0000         -624 print_link
  0.0  0.00  0.00   0.00  0.00   0.00  0.00     1   0.0000    0.0000           24 have_stats
  0.0  0.00  0.00   0.00  0.00   0.00  0.00     1   0.0000    0.0000          -72 make_submit
  0.0  0.00  0.00   0.00  0.00   0.00  0.00     2   0.0000    0.0000          112 strrchr
  0.0  0.08  0.08   0.00  0.00   0.00  0.00     2   0.0000    0.0000          168 filesize
  0.0  0.00  0.00   0.00  0.00   0.00  0.00     1   0.0000    0.0000          -16 commonfooter
  0.0  0.00  0.11   0.00  0.00   0.00  0.00     2   0.0000    0.0000            0 download_link
  0.0  0.00  0.25   0.00  0.01   0.00  0.00     6   0.0000    0.0017          208 make_image