269910 - Download progress reports incorrect speed at first

Status: VERIFIED DUPLICATE of bug 245725

(Toolkit :: Downloads API, defect)

Description

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User-Agent:       Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.7.5) Gecko/20041107 Firefox/1.0
Build Identifier: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.7.5) Gecko/20041107 Firefox/1.0

I've noticed that when downloading files, the initial download speed in KB/sec
is often artificially high.  It is far higher than is actually possible with my
connection, and then converges to the actual speed.

What I think is happening is that the downloaad time is only measured from after
the file dialog box is closed (to choose the destination file) but the current
size downloaded is measured since the file started downloading much earlier.  So
if the user takes a while to fill out his file chooser dialog, many KB will have
been downloaded already by the time the clock starts ticking.  So firefox (and
possibly other mozilla products) reports an artificially high download speed at
first.

Reproducible: Always
Steps to Reproduce:
1. Set the download setting "Ask where to save every file"
2. start downloading a large file (e.g.
http://ftp.mozilla.org/pub/mozilla.org/mozilla/releases/mozilla1.7.3/mozilla-mac-1.7.3.dmg.gz)
3. Wait some amount of time, (for example, 5 seconds)


Actual Results:  
Initial download speed is way too high, but converges down to an accurate
measure as time passes

Expected Results:  
Started the download clock from when the file actually started downloading.

OR

Make sure the download clock and the total bytes downloaded start at the same
time just for the purpose of the download speed figure.

Comment 1

[Phil Ringnalda (:philor)]

Me, I like that initial burst of speed ;)

*** This bug has been marked as a duplicate of 245725 ***