Re: Accurate queue times for uploads
The queue remaining time is calculated using a running average of the transfer speed over a 2 minute window, this is done to normalize the value when transferring small files and to handle situations where the there are huge variations in speed.
Typically I test between several specific servers on these servers I do not see any abnormal estimates in the queue remaining time.
Just recently I started tested against my router running vsftpd and uploading to a usb thumb drive, with this new test setup I am seeing a flaw in the logic used to calculate the estimated queue time, the first 100mb or so are transferred very fast 7-9MB/s and then the speed drops to around 5-6MB/s for another 100mb or so, then 2-4MB/s. The speed constantly drops over the duration of the 6 files (390mb) transferred, the queue takes about 1min 28 seconds to complete with an final average of 4.42MB/s. Now the queue remaining time is calculating an average speed of 6MB/s (over a 2min window) which in turn throws off the estimate.
In this type of situation the current logic is flawed. In the past we did some additional normalizing when calculating the average speed but this also had some issues with skewing the results.
I will investigate some alternative solutions and post back with a test build for you.
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