// live/dead over the same time period, so a good fit for batch
// allocation.

type BatchCounterAlloc struct {
	pool []uint32
}

func (ca *BatchCounterAlloc) AllocateCounters(n int) []uint32 {
	const chunk = 8192
	if n > cap(ca.pool) {
		siz := chunk
		if n > chunk {
			siz = n
		}
		ca.pool = make([]uint32, siz)
	}
	rv := ca.pool[:n]
	ca.pool = ca.pool[n:]
	return rv

				// Note: no overflow reporting here.
				if err, _ := ts.cm.MergeCounters(data.Counters, prev); err != nil {
					return fmt.Errorf("processing counter data file %s: %v", cdf, err)
				}
			}
			c := ts.AllocateCounters(len(data.Counters))
			copy(c, data.Counters)
			pmm[key] = c
		}
		return nil
	}

	// Read counter data files.
	for _, cdf := range p.CounterDataFiles {
		if err := readcdf(cdf); err != nil {