// Set to a nil channel.
		var _ch chan struct{}
		if val := globalServiceFreeze.Swap(_ch); val != nil {
			if ch, ok := val.(chan struct{}); ok && ch != nil {
				// Close previous non-nil channel.
				xioutil.SafeClose(ch)
			}
		}
		globalServiceFreezeCnt = 0 // Don't risk going negative.
	}
	globalServiceFreezeMu.Unlock()

}

// Get the max throughput and iops numbers.
func objectSpeedTest(ctx context.Context, opts speedTestOpts) chan madmin.SpeedTestResult {
	ch := make(chan madmin.SpeedTestResult, 1)
	go func() {
		defer xioutil.SafeClose(ch)

		concurrency := opts.concurrencyStart

		if opts.autotune {
			// if we have less drives than concurrency then choose
			// only the concurrency to be number of drives to start

	if p.offset+p.shardSize > p.shardFileSize {
		p.shardSize = p.shardFileSize - p.offset
	}
	if p.shardSize == 0 {
		return newBuf, nil
	}

	readTriggerCh := make(chan bool, len(p.readers))
	defer xioutil.SafeClose(readTriggerCh) // close the channel upon return

	for i := 0; i < p.dataBlocks; i++ {
		// Setup read triggers for p.dataBlocks number of reads so that it reads in parallel.
		readTriggerCh <- true
	}