ascknd

The following Perl PDQ¹; script was used to generate the response time data for the 8 core example in my https://ascknd.com/2014/05/02/nfs-vs-fibre-cpu-vmware/ post:

#/usr/bin/perl
use pdq;
$cores = $ARGV[0];
$servTime = $ARGV[1];
$max_rate = (1 / $servTime) * $cores;
print “response(secs)\t | util_%\n”;
for ($rate = 0; $rate < $max_rate ; $rate += $max_rate / 5) {

$arrivRate = $rate;
pdq::Init(“Open Network with M/M/N”);
pdq::SetComment(“Simulation of N CPU cores under transactional load.”);
pdq::CreateOpen(“work”, $arrivRate);
pdq::CreateMultiNode( $cores, “cores”, $pdq::CEN, $pdq::FCFS);
pdq::SetDemand(“cores”, “work”, $servTime);
pdq::SetWUnit(“IOS”);
pdq::SetTUnit(“Secs”);
pdq::Solve($pdq::CANON);
$response = substr(pdq::GetResponse($pdq::TRANS, “work”),0, 8);
$util = substr(pdq::GetUtilization(“cores”, “work”, $pdq::TRANS) * 100,0, 4);
printf “$response \t | % 4d\n”, $util;

}

perl ./mm8_response.pl 8 0.000127
response(secs) | util_%
0.000127 | 0
0.000127 | 20
0.000127 | 40
0.000132 | 60
0.000163 | 80

¹ http://www.perfdynamics.com/Tools/PDQcode.html

Tagged: Capacity, PDQ, performance, Perl, Queuing Theory

§ One Response to Perl PDQ: 8 core response time under load

• NFS vs Fibre Channel: Comparing CPU Utilization in VMWare | ascknd says:

  May 15, 2014 at 12:28 pm

  […] ← Why Are Mixed Workloads Bad? Perl PDQ: 8 core response time under load → […]

  Reply