@Test
  public void testPopulatefor1Kbwrites() {
    // RegionAttributes ra = region.getAttributes();
    // final String key = "K";
    final byte[] value = new byte[ENTRY_SIZE];
    Arrays.fill(value, (byte) 77);

    long startTime = System.currentTimeMillis();
    for (int i = 0; i < OP_COUNT; i++) {
      region.put("" + (i + 10000), value);
    }
    long endTime = System.currentTimeMillis();
    System.out.println(" done with putting");
    // Now get all the entries which are on disk.
    long startTimeGet = System.currentTimeMillis();
    for (int i = 0; i < OP_COUNT; i++) {
      region.get("" + (i + 10000));
    }
    long endTimeGet = System.currentTimeMillis();
    System.out.println(" done with getting");

    region.close(); // closes disk file which will flush all buffers
    float et = endTime - startTime;
    float etSecs = et / 1000f;
    float opPerSec = etSecs == 0 ? 0 : (OP_COUNT / (et / 1000f));
    float bytesPerSec = etSecs == 0 ? 0 : ((OP_COUNT * ENTRY_SIZE) / (et / 1000f));

    String stats = "et=" + et + "ms writes/sec=" + opPerSec + " bytes/sec=" + bytesPerSec;
    log.info(stats);
    System.out.println("Stats for 1 kb writes: :" + stats);
    // Perf stats for get op
    float etGet = endTimeGet - startTimeGet;
    float etSecsGet = etGet / 1000f;
    float opPerSecGet = etSecsGet == 0 ? 0 : (OP_COUNT / (etGet / 1000f));
    float bytesPerSecGet = etSecsGet == 0 ? 0 : ((OP_COUNT * ENTRY_SIZE) / (etGet / 1000f));

    String statsGet = "et=" + etGet + "ms gets/sec=" + opPerSecGet + " bytes/sec=" + bytesPerSecGet;
    log.info(statsGet);
    System.out.println("Perf Stats of get which is in memory :" + statsGet);
  }
Disk region Perf test for Overflow only with ASync writes. 1) Performance of get operation for
entry in memory.
geode-core/src/integrationTest/java/org/apache/geode/internal/cache/diskPerf/DiskRegOverflowAsyncGetInMemPerfJUnitTest.java