ProgressInfo::Estimates ProgressInfo::totalProgress() const
{
Estimates file = _fileProgress.estimates();
if (_sizeProgress._total == 0) {
return file;
}
Estimates size = _sizeProgress.estimates();
// Ideally the remaining time would be modeled as:
// remaning_file_sizes / transfer_speed
// + remaining_file_count * per_file_overhead
// + remaining_chunked_file_sizes / chunked_reassembly_speed
// with us estimating the three parameters in conjunction.
//
// But we currently only model the bandwidth and the files per
// second independently, which leads to incorrect values. To slightly
// mitigate this problem, we combine the two models depending on
// which factor dominates (essentially big-file-upload vs.
// many-small-files)
//
// If we have size information, we prefer an estimate based
// on the upload speed. That's particularly relevant for large file
// up/downloads, where files per second will be close to 0.
//
// However, when many *small* files are transfered, the estimate
// can become very pessimistic as the transfered amount per second
// drops significantly.
//
// So, if we detect a high rate of files per second or a very low
// transfer rate (often drops hugely during a sequence of deletes,
// for instance), we gradually prefer an optimistic estimate and
// assume the remaining transfer will be done with the highest speed
// we've seen.
// Compute a value that is 0 when fps is <=L*max and 1 when fps is >=U*max
double fps = _fileProgress._progressPerSec;
double fpsL = 0.5;
double fpsU = 0.8;
double nearMaxFps =
qBound(0.0,
(fps - fpsL * _maxFilesPerSecond) / ((fpsU - fpsL) * _maxFilesPerSecond),
1.0);
// Compute a value that is 0 when transfer is >= U*max and
// 1 when transfer is <= L*max
double trans = _sizeProgress._progressPerSec;
double transU = 0.1;
double transL = 0.01;
double slowTransfer = 1.0 - qBound(0.0,
(trans - transL * _maxBytesPerSecond) / ((transU - transL) * _maxBytesPerSecond),
1.0);
double beOptimistic = nearMaxFps * slowTransfer;
size.estimatedEta = (1.0 - beOptimistic) * size.estimatedEta
+ beOptimistic * optimisticEta();
return size;
}
bool ProgressInfo::trustEta() const
{
return totalProgress().estimatedEta < 100 * optimisticEta();
}
