ioniced/ioniced.pl

   1 #!/usr/bin/perl -w
   2
   3 # version 1.1, 05.12.2005, Hauke Laging, http://www.hauke-laging.de/software/
   4 # slightly edited by Jan Mette, spam-o-mat at nickname.berlin.de
   5 # This software is licensed under the Gnu GPL, see http://www.fsf.org/
   6
   7 # This script has the task to prevent I/O intensive system processes from
   8 # annoying the user by slowing the system down. These typical administrative
   9 # processes are not required to complete within a short time so it makes sense
  10 # to reduce the I/O priority of these tasks (which usually impacts the performance
  11 # of user processes much more than the CPU proirity).
  12 #
  13 # This script does not affect processes which have been niced to a value below zero
  14 # (higher priority) or already ioniced (to any value).
  15 # This is the most simple way to prevent a process from being affected by this script.
  16 # You can configure if a white list or black list approach is used: Either only the
  17 # configured programs are affected or only those not.
  18 #
  19 # The script runs as a daemon and reads the current PID list from ps every few
  20 # seconds. It cannot (or at least does not) prevent tasks from starting with
  21 # high I/O priority (high := high enough to annoy) but this problem es solved
  22 # after a few seconds.
  23 #
  24 # Thus this script should be started in the background. It writes to STDOUT what
  25 # it does/doesn't do.
  26 #
  27 # This script requires kernel 2.6.13 or above and the availability of ionice.
  28
  29 # definitions
  30 # signals:
  31 # USR1: The current list of known processes and their I/O priotity change status
  32 #       is dumped into the file $dump_file. Values 1,2 and 3 represent set priorities
  33 #       whereas 0 represents an unchanged priority.
  34
  35 @args = ("/bin/bash","-c","type ionice");
  36 system(@args);
  37 if ($? != 0)
  38 {
  39         print "The program 'ionice' is not available; aborting.\n";
  40         exit 1;
  41 }
  42
  43 use integer;
  44
  45 #
  46 # configuration
  47 #
  48 $min_user_id = 100;
  49 $max_user_id = 200;
  50 $syslog_tag="ioniced.pl";
  51 $0=$syslog_tag;
  52 # poll interval
  53 $sleep = 3;
  54 $leave_inid_pids_untouched=0;
  55 $whitelist=1;
  56 $dump_file="/tmp/ioniced.dump";
  57 %known_pids = (); # Werte: 1,2,3 fuer die gesetzten, 0 fuer die unveraenderten
  58
  59 #
  60 # processes that should be skipped
  61 #
  62 %skip_these = ("init"=>0,"ps"=>0,"sshd"=>0,"syslog-ng"=>0,"httpd2-prefork"=>0,"pdflush"=>0); # values: dummys
  63
  64 #
  65 # processes that should be ioniced
  66 #
  67 %ionice_these = (find=>3,tar=>3,updatedb=>3,mandb=>3,cp=>3,mv=>3,rpm=>3,gzip=>3,kio_file=>3); # values: new I/O priority level
  68
  69
  70
  71 ############ DO NOT EDIT BELOW THIS LINE ############
  72
  73 sub dump_ioprios {
  74         if (not open(FH,"> $dump_file"))
  75         {
  76                 return;
  77         }
  78         foreach (keys %known_pids)
  79         {
  80                 print FH $_," ",$known_pids{$_},"\n";
  81         }
  82         close(FH);
  83 }
  84
  85 $SIG{USR1}="dump_ioprios";
  86
  87 # BEGIN: initialize the hash with the present pids
  88 @pslines = qx/ps -eo pid,ruid,nice,comm/;
  89 $i=0;
  90 foreach (@pslines)
  91 {
  92         $i++;
  93         next if $i == 1; # header line pf ps output
  94         $_ =~ s/^\s+//;
  95         $_ =~ s/\s+$//;
  96         @elements = split(" +",$_);
  97         $pid=$elements[0];
  98         $ruid=$elements[1];
  99         $nice=$elements[2];
 100         $command=$elements[3];
 101         $change_it=1;
 102         $change_it=0 if ($leave_inid_pids_untouched);
 103         $change_it=0 if ($ruid>=$min_user_id && $ruid<=$max_user_id);
 104         $change_it=0 if ($nice<0);
 105         $change_it=0 if (exists($skip_these{$command}));
 106         if ($change_it) # execute this one conditionally only because it takes time
 107         {
 108                 $ionice_status=qx/ionice -p $pid/;
 109                 $ionice_status =~ s/:.*$//;
 110                 $change_it=0 if ($ionice_status != "none");
 111         }
 112         if ($whitelist)
 113         {
 114                 $change_it=0 unless (exists($ionice_these{$command}));
 115         }
 116         if ($change_it)
 117         {
 118                 $io_class=3;
 119                 $explicit_io_class=$ionice_these{$command};
 120                 if ($whitelist && defined($explicit_io_class) && ($explicit_io_class eq 1 || $explicit_io_class eq 2 || $explicit_io_class eq 3))
 121                 {
 122                         $io_class=$explicit_io_class;
 123                 }
 124                 $known_pids{$pid}=$io_class;
 125                 system("ionice -c${io_class} -p${pid}");
 126                 print "PID ${pid} ($command) has been changed to I/O class ${io_class}.\n";
 127                 if ($whitelist)
 128                 {
 129                         system("logger -t \"${syslog_tag}\" \"PID ${pid} ($command) has been changed to I/O class ${io_class}.\"");
 130                 }
 131         }
 132         else
 133         {
 134                 $known_pids{$pid}=0;
 135                 print "PID ${pid}'s ($command) I/O class has not been changed.\n"
 136         }
 137 }
 138 print "Initialization finished.\n";
 139 # END: initialize the hash with the present pids
 140
 141 while (1)
 142 {
 143         sleep $sleep;
 144         print "\n\nChecking for new PIDs:\n";
 145         @pslines = qx/ps -eo pid,ruid,nice,comm/;
 146         $i=0;
 147         %current_pids=(); # Werte: Dummys
 148         foreach (@pslines)
 149         {
 150                 $i++;
 151                 next if $i == 1; # header line pf ps output
 152                 $_ =~ s/^\s+//;
 153                 $_ =~ s/\s+$//;
 154                 @elements = split(" +",$_);
 155                 $pid=$elements[0];
 156                 $ruid=$elements[1];
 157                 $nice=$elements[2];
 158                 $command=$elements[3];
 159                 $current_pids{$pid}=0;
 160                 next if (exists($known_pids{$pid}));
 161                 next if ($command eq "ps");
 162                 $change_it=1;
 163                 $change_it=0 if ($ruid>=$min_user_id && $ruid<=$max_user_id);
 164                 $change_it=0 if ($nice<0);
 165                 $change_it=0 if (exists($skip_these{$command}));
 166                 if ($change_it) # execute this one conditionally only because it takes time
 167                 {
 168                         $ionice_status=qx/ionice -p $pid/;
 169                         $ionice_status =~ s/:.*$//;
 170                         chomp($ionice_status);
 171                         $change_it=0 if ($ionice_status ne "none");
 172                 }
 173                 if ($whitelist)
 174                 {
 175                         $change_it=0 unless (exists($ionice_these{$command}));
 176                 }
 177                 if ($change_it)
 178                 {
 179                         $io_class=3;
 180                         $explicit_io_class=$ionice_these{$command};
 181                         if ($whitelist && defined($explicit_io_class) && ($explicit_io_class eq 1 || $explicit_io_class eq 2 || $explicit_io_class eq 3))
 182                         {
 183                                 $io_class=$explicit_io_class;
 184                         }
 185                         $known_pids{$pid}=$io_class;
 186                         system("ionice -c${io_class} -p${pid}");
 187                         print "PID ${pid} ($command) has been changed to I/O class ${io_class}.\n";
 188                         if ($whitelist)
 189                         {
 190                                 system("logger -t \"${syslog_tag}\" \"PID ${pid} ($command) has been changed to I/O class ${io_class}.\"");
 191                         }
 192                 }
 193                 else
 194                 {
 195                         $known_pids{$pid}=0;
 196                         print "PID ${pid}'s ($command) I/O class has not been changed.\n"
 197                 }
 198         }
 199         print "\n\nPID check\n";
 200         foreach (keys %known_pids)
 201         {
 202                 unless (exists($current_pids{$_}))
 203                 {
 204                         delete($known_pids{$_});
 205                         print "PID ",$_," does not exist any more and has been deleted from the hash.\n";
 206                 }
 207         }
 208 }