watch your scoreboard file...

[Rob Hartill <ha...@ooo.lanl.gov>]

I wrote a perl script to monitor the scoreboard file. It is
attached to this mail.

Here's a snapshot of it's output as seen running at Cardiff...

ssssssR_RsRss (3/12)   


The first string represent the first 13 entries of the scoreboard
file, 
  s -  sleeping (as good as) waiting for accept
  R -  running, i.e. not waiting for an accept.
  _ -  dead process or a free entry in the table.


Fire the script up with a numeric argument and each update will be
that many seconds appart.
It can easily be converted into a scoreboard log file.

Kinda cute,



#!/usr/local/bin/perl

# 
# Author: Rob Hartill     hartill@lanl.gov
#
# simple script to monitor Apache processes
#   If you give it a numeric argument, it's used as a interval
#      e.g.   script 3     
#                Will give you an update ever 3 seconds
#                If you choose 0, it might chew up lots of CPU time.
#                default interval = 1 second


$PID_FILE = "/usr/local/httpd/logs/httpd.pid";
$MAX_PROC = 40;    # we never have (or are interested in) more than 40 procs


############ nothing worth looking at beyond this point ##############

select STDOUT; $| = 1;

$delay = @ARGV[0];
$delay = 1 unless $delay =~ /^[0-9]+$/ ;

open (P, "$PID_FILE") || die "Unable to open $PID_FILE";
$PID = <P>;
$ext = sprintf("a%05d", $PID);
close(P);

open (SB, "/tmp/htstatus.$ext") || die "Unable to open scoreboard file /tmp/htstatus.$ext";

$last_len = 0;
while (1) {

  if ( ($last_mod = (stat("/tmp/htstatus.$ext"))[9]) != $before) {
    open (SB, "/tmp/htstatus.$ext") || die "Unable to open scoreboard file /tmp/htstatus.$ext";
    seek(SB, 2 , 0);
  
    $len = 0; $pad =""; $running = 0; $dead = 0;  $total=0;
    for ( $child=1; $child<=$MAX_PROC; $child++) {

       read(SB, $p1, 1);       # 2nd word = process number
       read(SB, $p2, 1);       # 2nd word = process number
       $p = hex(sprintf("%02X%02X", ord($p1), ord($p2)));

       read(SB, $status, 1);  # next byte = status
       $status = ord($status);
     
       read(SB, $junk, 5);    # skip to next entry
          
       $c = sprintf("%X", $child);
       
       if ($p != 0 && $p != $PID) {
         $total++;
         if ($status == 1) {
            $c = "s";
         } else {
            $c = "R";
            ++$running;
         }
         $printed .= "$pad$c";
         
         $pad = ""; 
         $dead = 0;
       } else {
            $dead++;
            $pad = "_"x$dead;
       } 
    }
    $printed .= " ($running/$total)";
    $len = length($printed);  
    
    if ($last_len > $len) {
       print "\010"x$last_len ;
       print " "x$last_len ;
       print "\010"x$last_len ;
    } else {
       print "\010"x$len ;
    }
    print $printed; $printed = "";

    $before = $last_mod;
    close(SB);
    $last_len = $len;
   }
   sleep($delay) if $delay >0;
}