Method FindDevice

query/device_manager.go:140–181

FindDevice finds a device to run a given query. If a device is not found, it will wait until the DeviceChoosingTimeout seconds elapse.

(query *queryCom.AQLQuery, requiredMem int, preferredDevice int, timeout int)

// FindDevice finds a device to run a given query. If a device is not found, it will wait until
// the DeviceChoosingTimeout seconds elapse.
func (d *DeviceManager) FindDevice(query *queryCom.AQLQuery, requiredMem int, preferredDevice int, timeout int) int {
	if requiredMem > d.MaxAvailableMemory {
		utils.GetQueryLogger().With(
			"query", query,
			"requiredMem", requiredMem,
			"preferredDevice", preferredDevice,
			"maxAvailableMem", d.MaxAvailableMemory,
		).Warn("exceeds max memory")
		return -1
	}

	// no DeviceChoosingTimeout passed by request, using default DeviceChoosingTimeout.
	if timeout <= 0 {
		timeout = d.Timeout
	}

	timeoutDuration := time.Duration(timeout) * time.Second

	start := utils.Now()
	d.Lock()
	device := -1
	for {
		if utils.Now().Sub(start) >= timeoutDuration {
			utils.GetQueryLogger().With(
				"query", query,
				"requiredMem", requiredMem,
				"preferredDevice", preferredDevice,
				"timeout", timeout,
			).Error("DeviceChoosingTimeout when choosing the device for the query")
			break
		}

		device = d.findDevice(query, requiredMem, preferredDevice)
		if device >= 0 {
			break
		}
		d.deviceAvailable.Wait()
	}
	d.Unlock()
	utils.GetRootReporter().GetTimer(utils.QueryWaitForMemoryDuration).Record(utils.Now().Sub(start))
	return device
}

// findDevice finds a device to run a given query according to certain strategy.If no such device can't
// be found, return -1. Caller needs to hold the write lock.