t.Error("got objects", e.Objects, "want", w.objs)
			}
			if e.Versions != uint64(w.objs) {
				t.Error("got versions", e.Versions, "want", w.objs)
			}
			if e.ObjSizes != w.oSizes {
				t.Error("got histogram", e.ObjSizes, "want", w.oSizes)
			}
		})
	}

	files = []usageTestFile{
		{
			name: "newfolder/afile",
			size: 4,
		},
		{
			name: "newfolder/anotherone",
			size: 1,
		},

	sync.RWMutex  // protects requestsCount only
	requestsCount map[string]struct {
		success int64
		failure int64
	}
	histogram *prometheus.HistogramVec
}

var globalTierMetrics = tierMetrics{
	requestsCount: make(map[string]struct {
		success int64
		failure int64
	}),
	histogram: prometheus.NewHistogramVec(prometheus.HistogramOpts{
		Name:    "tier_ttlb_seconds",

// dataUsageHash is the hash type used.
type dataUsageHash string

// sizeHistogramV1 is size histogram V1, which has fewer intervals esp. between
// 1024B and 1MiB.
type sizeHistogramV1 [dataUsageBucketLenV1]uint64

// sizeHistogram is a size histogram.
type sizeHistogram [dataUsageBucketLen]uint64

// versionsHistogram is a histogram of number of versions in an object.
type versionsHistogram [dataUsageVersionLen]uint64

}

func (bh *bucketHTTPStats) updateHTTPStats(bucket, api string, w *xhttp.ResponseRecorder) {
	if bh == nil {
		return
	}

	if w != nil {
		// Increment the prometheus http request response histogram with API, Bucket
		bucketHTTPRequestsDuration.With(prometheus.Labels{
			"api":    api,
			"bucket": bucket,
		}).Observe(w.TTFB().Seconds())
	}

	bh.Lock()
	defer bh.Unlock()

   ([#123611](https://github.com/kubernetes/kubernetes/pull/123611), [@ritazh](https://github.com/ritazh))

*   `tf.keras`:

    *   Changed the TensorBoard tag names produced by the
        `tf.keras.callbacks.TensorBoard` callback, so that summaries logged
        automatically for model weights now include either a `/histogram` or
        `/image` suffix in their tag names, in order to prevent tag name
        collisions across summary types.

*   When running on GPU (with cuDNN version 7.6.3 or