modules/gemfire-modules/src/main/java/com/gemstone/gemfire/modules/util/ResourceManagerValidator.java

/*=========================================================================
 * Copyright (c) 2010-2014 Pivotal Software, Inc. All Rights Reserved.
 * This product is protected by U.S. and international copyright
 * and intellectual property laws. Pivotal products are covered by
 * one or more patents listed at http://www.pivotal.io/patents.
 *=========================================================================
 */
package com.gemstone.gemfire.modules.util;

import java.lang.management.ManagementFactory;
import java.lang.management.RuntimeMXBean;
import java.util.ArrayList;
import java.util.List;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

import com.gemstone.gemfire.cache.GemFireCache;
import com.gemstone.gemfire.cache.control.ResourceManager;

public class ResourceManagerValidator {
  
  private static final Pattern DIGIT_PATTERN = Pattern.compile("(\\d+|[^\\d]+)");

  public static void validateJavaStartupParameters(GemFireCache cache) {
    // Get the input arguments
    ResourceManager rm = cache.getResourceManager();
    RuntimeMXBean runtimeBean = ManagementFactory.getRuntimeMXBean();
    List<String> inputArguments = runtimeBean.getInputArguments();
    if (cache.getLogger().fineEnabled()) {
      cache.getLogger().fine("Full input java arguments: " + inputArguments);
    }
    
    // Validate the arguments based on VM vendor
    String vmVendor = runtimeBean.getVmVendor();
    if (vmVendor.startsWith("Sun") || vmVendor.startsWith("Apple")) {
      // java.vm.vendor = Sun Microsystems Inc. || java.vm.vendor = Apple Inc.
      validateSunArguments(cache, rm, inputArguments);
    } else if (vmVendor.startsWith("IBM")) {
      // java.vm.vendor = IBM Corporation
      // TODO validate IBM input arguments
    } else if (vmVendor.startsWith("BEA")) {
      // java.vm.vendor = BEA Systems, Inc.
      // TODO validate JRockit input arguments
    }
  }
  
  private static void validateSunArguments(GemFireCache cache, ResourceManager rm, List<String> inputArguments) {
    // Retrieve the -Xms, -Xmx, UseConcMarkSweepGC and CMSInitiatingOccupancyFraction arguments
    String dashXms=null, dashXmx=null, useCMS=null, cmsIOF=null;
    for (String argument : inputArguments) {
      if (argument.startsWith("-Xms")) {
        dashXms = argument;
      } else if (argument.startsWith("-Xmx")) {
        dashXmx = argument;
      } else if (argument.equals("-XX:+UseConcMarkSweepGC")) {
        useCMS = argument;
      } else if (argument.startsWith("-XX:CMSInitiatingOccupancyFraction")) {
        cmsIOF = argument;
      }
    }
    if (cache.getLogger().fineEnabled()) {
      StringBuilder builder = new StringBuilder();
      builder
        .append("Relevant input java arguments: ")
        .append("dashXms=")
        .append(dashXms)
        .append("; dashXmx=")
        .append(dashXmx)
        .append("; useCMS=")
        .append(useCMS)
        .append("; cmsIOF=")
        .append(cmsIOF);
      cache.getLogger().fine(builder.toString());
    }
    
    // Validate the heap parameters
    validateJavaHeapParameters(cache, dashXms, dashXmx);
    
    // Verify CMS is specified
    verifyCMSGC(cache, useCMS);
    
    // Verify CMSInitiatingOccupancyFraction is specified
    verifyCMSInitiatingOccupancyFraction(cache, rm, cmsIOF);
  }
  
  private static void validateJavaHeapParameters(GemFireCache cache, String dashXms, String dashXmx) {
    if (dashXms == null) {
      cache.getLogger().warning("Setting the initial size of the heap (configured using -Xms) is recommended so that GemFire cache eviction is optimal");
    } else if (dashXmx == null) {
      cache.getLogger().warning("Setting the maximum size of the heap (configured using -Xmx) is recommended so that GemFire cache eviction is optimal");
    } else {
      // Neither heap parameter is null. Parse them and verify they are the same.
      List<String> dashXmsList = splitAtDigits(dashXms);
      String dashXmsStr = dashXmsList.get(1);
      List<String> dashXmxList = splitAtDigits(dashXmx);
      String dashXmxStr = dashXmxList.get(1);
      if (!dashXmsStr.equals(dashXmxStr)) {
        StringBuilder builder = new StringBuilder();
        builder
          .append("Setting the initial (")
          .append(dashXmsStr)
          .append(dashXmsList.get(2))
          .append(") and maximum (")
          .append(dashXmxStr)
          .append(dashXmxList.get(2))
          .append(") sizes of the heap the same is recommended so that GemFire cache eviction is optimal");
        cache.getLogger().warning(builder.toString());
      }
    }
  }
  
  private static void verifyCMSGC(GemFireCache cache, String useCMS) {
    if (useCMS == null) {
      cache.getLogger().warning("Using the concurrent garbage collector (configured using -XX:+UseConcMarkSweepGC) is recommended so that GemFire cache eviction is optimal");
    }  
  }
  
  private static void verifyCMSInitiatingOccupancyFraction(GemFireCache cache, ResourceManager rm, String cmsIOF) {
    if (cmsIOF == null) {
      cache.getLogger().warning("Setting the CMS initiating occupancy fraction (configured using -XX:CMSInitiatingOccupancyFraction=N) is recommended so that GemFire cache eviction is optimal");
    } else {
      // Parse the CMSInitiatingOccupancyFraction. Verify it is less than both eviction and critical thresholds.
      int cmsIOFVal = Integer.parseInt(cmsIOF.split("=")[1]);
      float currentEvictionHeapPercentage = rm.getEvictionHeapPercentage();
      if (currentEvictionHeapPercentage !=0 && currentEvictionHeapPercentage < cmsIOFVal) {
        cache.getLogger().warning("Setting the CMS initiating occupancy fraction (" + cmsIOFVal + ") less than the eviction heap percentage (" + currentEvictionHeapPercentage + ") is recommended so that GemFire cache eviction is optimal");
      }
      float currentCriticalHeapPercentage = rm.getCriticalHeapPercentage();
      if (currentCriticalHeapPercentage !=0 && currentCriticalHeapPercentage < cmsIOFVal) {
        cache.getLogger().warning("Setting the CMS initiating occupancy fraction (" + cmsIOFVal + ") less than the critical heap percentage (" + currentCriticalHeapPercentage + ") is recommended so that GemFire cache eviction is optimal");
      }
    }
  }
  
  private static List<String> splitAtDigits(String input) {
    Matcher matcher = DIGIT_PATTERN.matcher(input);
    List<String> result = new ArrayList<String>();
    while (matcher.find()) {
      result.add(matcher.group());
    }
    return result;
  }

  private ResourceManagerValidator() {}

}