The Staged Event-Driven Architecture (SEDA) is a new design for building scalable Internet services.

				#!/usr/bin/perl								$MIN_RATE = 64;				$MAX_RATE = 1024;				$CFG = "exp-cpu-rtcon.cfg";				$TARGET_RT = 200.0;								$SEC_PER_RUN = 100;								$date = `date`; chop $date;				$local = `hostname`; chop $local;				print "# Running Simple-SA benchmark at $date\n";				print "# Running on $local\n";				print "# Rate\tThroughput\tAvg RT\tMax RT\t90th pct RT\tFrac Rej\n";								for ($rate = $MIN_RATE; $rate 				  $nummsgs = $rate * $SEC_PER_RUN;				  $CMD = "sandstorm $CFG rate=$rate num_msgs=$nummsgs global.rtController.targetResponseTime=$TARGET_RT 2>&1";				#print "# CMD: $CMD\n";				  open(CMD, "$CMD|") || die "Can't run $CMD\n";				  open(TMPFILE, ">/tmp/mdw.run.$$") || die "Can't open tmpfile\n";				  open(TMPFILEREJ, ">/tmp/mdw.rej.$$") || die "Can't open tmpfilerej\n";								  while () {				#print "# READ: $_";								    if (/^Overall rate:\s+(\S+) msgs/) {				      $throughput = $1;				    }								    if (/^(\d+) rejected, fraction (\S+)/) {				      $rejfrac = $2;				    }								    if (/^RT (\S+) ms (\S+) count/) {				      print TMPFILE;				    }								    if (/^REJRT (\S+) ms (\S+) count/) {				      print TMPFILEREJ;				    }				  }				  close(TMPFILE);				  close(CMD);								  $SCMD = "cat /tmp/mdw.run.$$ | stats.pl -c 4 2";				  open (SCMD, "$SCMD|") || die "Can't run $SCMD\n";				  while () {				    if (/^mean: (\S+)/) {				      $avg_rt = $1;				    }				    if (/^max: (\S+)/) {				      $max_rt = $1;				    }				    if (/^stddev: (\S+)/) {				      $stddev_rt = $1;				    }				    if (/^90th percentile: (\S+)/) {				      $nth_rt = $1;				    }				  }				  close(SCMD);				  `rm -f /tmp/mdw.run.$$`;								  `rm -f /tmp/mdw.rej.$$`;								  print "$rate\t$throughput\t$avg_rt\t$max_rt\t$nth_rt\t$rejfrac\n";								}