Mac OS X Port Using HotSpot DTrace Probes

% sudo /usr/sbin/dtrace -n 'hotspot$1:::gc-end{printf("GC: %d\n", timestamp);}' 1213
dtrace: description 'hotspot$1:::gc-end' matched 2 probes
CPU     ID                    FUNCTION:NAME
  0  23653 _ZN15VM_GC_Operation13notify_gc_endEv:gc-end GC: 334679181

  1  23653 _ZN15VM_GC_Operation13notify_gc_endEv:gc-end GC: 1487377551

  0  23653 _ZN15VM_GC_Operation13notify_gc_endEv:gc-end GC: 3231453137

hotspot$1:::gc-end
{
  printf("GC: %d\n", timestamp);
}

% sudo /usr/sbin/dtrace -s gcEnd.d 1213

% sudo /usr/sbin/dtrace -l 1213 | grep hotspot
23638 hotspot1213      libjvm.dylib _ZN13instanceKlass15initialize_implE19instanceKlassHandleP6Thread [instanceKlass::initialize_impl] class-initialization-clinit
23639 hotspot1213      libjvm.dylib _ZN13instanceKlass15initialize_implE19instanceKlassHandleP6Thread [instanceKlass::initialize_impl] class-initialization-concurrent
23640 hotspot1213      libjvm.dylib _ZN13instanceKlass15initialize_implE19instanceKlassHandleP6Thread [instanceKlass::initialize_impl] class-initialization-end
23641 hotspot1213      libjvm.dylib _ZN13instanceKlass15initialize_implE19instanceKlassHandleP6Thread [instanceKlass::initialize_impl] class-initialization-erroneous
23642 hotspot1213      libjvm.dylib _ZN13instanceKlass15initialize_implE19instanceKlassHandleP6Thread [instanceKlass::initialize_impl] class-initialization-error
...

long startTime;
hotspot$1:::gc-begin
{
  startTime = timestamp;
}
hotspot$1:::gc-end
{
  printf("GC time interval: %d\n", timestamp-startTime);
}

 -XX:+DTraceMethodProbes
 -XX:+DTraceAllocProbes
 -XX:+DTraceMonitorProbes

 -XX:+ExtendedDTraceProbes

% java -XX:+ExtendedDTraceProbes -jar /Developer/Extras/Java/JFC/Java2D/Java2D.jar

% sudo /usr/sbin/dtrace -s object_allocation_stat.d -p 1444
^C
 Top 100 allocations by size:
        40 java/lang/ref/SoftReference
       192 [C
       192 java/lang/String
      2016 sun/java2d/loops/GraphicsPrimitiveMgr$PrimitiveSpec

#!/usr/sbin/dtrace -Zs

#pragma D option quiet
#pragma D option destructive
#pragma D option defaultargs
#pragma D option bufsize=16m
#pragma D option aggrate=100ms

/*
 * Usage:
 *      object_allocation_stat.d -p JAVA_PID [PAUSE_AT_STARTUP_FILE]
 *
 * This script collects statistics about object allocations.
 *
 * Notes:
 *  - this probes are available only with '-XX:+ExtendedDtraceProbes' option,
 *      so pass this option too.
 *  - This script SLOW DOWN your java application. So, not be surprised :)
 *
 *
 * Note that Hotspot probes definitions are located in libjvm.so and
 * straightforward attempt to run d-script may fail, e.g.:
 *      ./dscript.d -c "java HelloWorld"
 *      "probe description hotspotPID:::probename does not match any probes"
 * This is because dtrace tries to enable probes before libjvm.so is loaded.
 *
 * To avoid this use one of following options to start java:
 * 1) -XX:+PauseAtStartup 
 * 2) -XX:+PauseAtStartup -XX:PauseAtStartupFile=FILENAME
 *
 * In first case the file named 'vm.paused.JAVA_PID' will be created and
 *  then java process will be paused till 'vm.paused.JAVA_PID' will be deleted.
 * In second case jvm will wait till 'FILENAME' will be deleted.
 * 
 * Then you can launch d-script you want to run by passing JAVA_PID as -p <JAVA_PID>
 * and delete PAUSE_AT_STARTUP_FILE manually or by passing it as first argument 
 * (PAUSE_AT_STARTUP_FILE) to d-script.
 * 
 * NB: -XX:+PauseAtStartup requires -XX:+UnlockDiagnosticVMOptions
 *
 */

self char *str_ptr;
self string class_name;

long long ALLOCATED_OBJECTS_CNT;

string PAUSE_AT_STARTUP_FILE;

:::BEGIN
/ $1 != "" /
{
    PAUSE_AT_STARTUP_FILE = $1;

    printf("rm %s\n\n", PAUSE_AT_STARTUP_FILE);
    system("rm %s", PAUSE_AT_STARTUP_FILE);
}

BEGIN
{
    TOP_N = 100;
    ALLOCATED_OBJECTS_CNT = 0;
}

/*
 * hotspot:::object-alloc probe arguments:
 *  arg0: uintptr_t,    Java thread id
 *  arg1: char*,        a pointer to mUTF-8 string containing the name of
 *                          the class of the object being allocated
 *  arg2: uintptr_t,    the length of the class name (in bytes)
 *  arg3: uintptr_t,    the size of the object being allocated
 */
hotspot$target:::object-alloc
{
    ALLOCATED_OBJECTS_CNT ++;

    self->str_ptr = (char*) copyin(arg1, args[2]+1);
    self->str_ptr[args[2]] = '\0';
    self->class_name = (string) self->str_ptr;


    @allocs_count[self->class_name] = count();
    @allocs_size[self->class_name] = sum(args[3]);

/*
    printf("%s:\t[%u] class_name=%s (len=%u), size=%u\n",
        probename, args[0], self->class_name, args[2], args[3]);
*/
}

:::END
{
    printf("Top %d allocations by size:\n", TOP_N);
    trunc(@allocs_size, TOP_N);
    printa("%10@d %s\n", @allocs_size);

    printf("\n");
    printf("Top %d allocations by count:\n", TOP_N);
    trunc(@allocs_count, TOP_N);
    printa("%10@d %s\n", @allocs_count);

    printf("\nTotal number of allocated objects: %d\n", ALLOCATED_OBJECTS_CNT);
}