/**
Copyright (C) SYSTAP, LLC DBA Blazegraph 2006-2016. All rights reserved.
Contact:
SYSTAP, LLC DBA Blazegraph
2501 Calvert ST NW #106
Washington, DC 20008
licenses@blazegraph.com
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; version 2 of the License.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
package com.bigdata.rdf.sail.webapp.lbs.policy.ganglia;
import com.bigdata.rdf.sail.webapp.lbs.IHostMetrics;
import com.bigdata.rdf.sail.webapp.lbs.IHostScoringRule;
/**
* Best effort computation of a workload score based on CPU Utilization and IO
* Wait defined as follows:
*
* <pre>
* (1d + cpu_wio * 100d) / (1d + cpu_idle)
* </pre>
* <p>
* Note: Not all platforms report all metrics. For example, OSX does not report
* IO Wait, which is a key metric for the workload of a database. If a metric is
* not available for a host, then a fallback value is used.
*
* @author <a href="mailto:thompsonbry@users.sourceforge.net">Bryan Thompson</a>
*
* FIXME GC time is a per-JVM metric that should be incorporated into our
* default scoring strartegy. It will only get reported by the
* ganglia plug in if it is setup to self-report that data. And it
* may not report it correctly if there is more than one
* {@link HAJournalService} per host. It is also available from the
* <code>/bigdata/counters</code> and could be exposed as a JMX MBean.
*/
public class DefaultHostScoringRule implements IHostScoringRule {
private static final String CPU_IDLE = "cpu_idle";
private static final String CPU_WIO = "cpu_wio";
@Override
public String[] getMetricNames() {
return new String[]{CPU_IDLE, CPU_WIO};
}
@Override
public double getScore(final IHostMetrics metrics) {
final double cpu_idle = metrics.getNumeric(CPU_IDLE, .5d);
final double cpu_wio = metrics.getNumeric(CPU_WIO, .05d);
final double hostScore = (1d + cpu_wio * 100d) / (1d + cpu_idle);
return hostScore;
}
}