src/jdk.jcmd/share/classes/sun/tools/jmap/JMap.java

*** 167,176 ****
--- 167,177 ----
      private static void histo(String pid, String options)
          throws AttachNotSupportedException, IOException,
                 UnsupportedEncodingException {
          String liveopt = "-all";
          String filename = null;
+         String parallel = null;
          String subopts[] = options.split(",");
  
          for (int i = 0; i < subopts.length; i++) {
              String subopt = subopts[i];
              if (subopt.equals("") || subopt.equals("all")) {
*** 178,198 ****
              } else if (subopt.equals("live")) {
                  liveopt = "-live";
              } else if (subopt.startsWith("file=")) {
                  filename = parseFileName(subopt);
                  if (filename == null) {
!                     usage(1); // invalid options or no filename
                  }
              } else {
!                 usage(1);
              }
          }
- 
          System.out.flush();
  
          // inspectHeap is not the same as jcmd GC.class_histogram
!         executeCommandForPid(pid, "inspectheap", liveopt, filename);
      }
  
      private static void dump(String pid, String options)
          throws AttachNotSupportedException, IOException,
                 UnsupportedEncodingException {
--- 179,206 ----
              } else if (subopt.equals("live")) {
                  liveopt = "-live";
              } else if (subopt.startsWith("file=")) {
                  filename = parseFileName(subopt);
                  if (filename == null) {
!                     System.err.println("Fail: invalid option or no file name '" + subopt +"'");
!                     System.exit(1);
!                 }
!             } else if (subopt.startsWith("parallel=")) {
!                parallel = subopt.substring("parallel=".length());
!                if (parallel == null) {
!                     System.err.println("Fail: no number provided in option: '" + subopt + "'");
!                     System.exit(1);
                 }
              } else {
!                 System.err.println("Fail: invalid option: '" + subopt + "'");
!                 System.exit(1);
              }
          }
          System.out.flush();
  
          // inspectHeap is not the same as jcmd GC.class_histogram
!         executeCommandForPid(pid, "inspectheap", liveopt, filename, parallel);
      }
  
      private static void dump(String pid, String options)
          throws AttachNotSupportedException, IOException,
                 UnsupportedEncodingException {
*** 209,219 ****
                  filename = parseFileName(subopt);
              }
          }
  
          if (filename == null) {
!             usage(1);  // invalid options or no filename
          }
  
          // dumpHeap is not the same as jcmd GC.heap_dump
          executeCommandForPid(pid, "dumpheap", filename, liveopt);
      }
--- 217,228 ----
                  filename = parseFileName(subopt);
              }
          }
  
          if (filename == null) {
!             System.err.println("Fail: invalid option or no file name");
!             System.exit(1);
          }
  
          // dumpHeap is not the same as jcmd GC.heap_dump
          executeCommandForPid(pid, "dumpheap", filename, liveopt);
      }
*** 285,294 ****
--- 294,307 ----
          System.err.println("");
          System.err.println("    histo-options:");
          System.err.println("      live         count only live objects");
          System.err.println("      all          count all objects in the heap (default if one of \"live\" or \"all\" is not specified)");
          System.err.println("      file=<file>  dump data to <file>");
+         System.err.println("      parallel=<number>  parallel threads number for heap iteration:");
+         System.err.println("                                  parallel=0 default behavior, use predefined number of threads");
+         System.err.println("                                  parallel=1 disable parallel heap iteration");
+         System.err.println("                                  parallel=<N> use N threads for parallel heap iteration");
          System.err.println("");
          System.err.println("    Example: jmap -histo:live,file=/tmp/histo.data <pid>");
          System.exit(exit);
      }
  }