Hi All,
I recently started migrating to libcurl 8.4.0 from 7.84.0 in some of my
applications and noticed a seeming regression for CURLOPT_MAX_RECV_SPEED_LARGE
option precision.
I use this option for download speed throttling, and it worked very well in
7.84.0 with a very good 5% precision.
But with 8.4.0, I see very big deviations (both higher and lower) - up to 20%,
which negatively affect throttling features.
Here is a snapshot of my test logs illustrating the problem:
[7.84.0] < 5% deviation from CURLOPT_MAX_RECV_SPEED_LARGE:
max_speed=8000000 bps (1000000 B/s), 5MB download HTTP 1.1
tfrt=5258ms, dnld=5242880, spd=7976608 bps
tfrt=5261ms, dnld=5242880, spd=7972136 bps
tfrt=5254ms, dnld=5242880, spd=7982592 bps
max_speed=16000000 bps (2000000 B/s), 5MB download HTTP 1.1
tfrt=2625ms, dnld=5242880, spd=15975112 bps
tfrt=2621ms, dnld=5242880, spd=16002032 bps
tfrt=2620ms, dnld=5242880, spd=16005744 bps
[8.4.0] up to 20% deviation from CURLOPT_MAX_RECV_SPEED_LARGE:
max_speed=8000000 bps (1000000 B/s), 5MB download HTTP 1.1
tfrt=5750ms, dnld=5242880, spd=7294240 bps
tfrt=6935ms, dnld=5242880, spd=6047488 bps
tfrt=6540ms, dnld=5242880, spd=6412544 bps
max_speed=16000000 bps (2000000 B/s), 5MB download HTTP 1.1
tfrt=2541ms, dnld=5242880, spd=16506120 bps
tfrt=2470ms, dnld=5242880, spd=16974568 bps
tfrt=2834ms, dnld=5242880, spd=14796072 bps
I can see such big speed deviations regardless the network speed and download
sizes.
I know that it is not easy to provide a very good speed precision, but such
large speed swings don't seem right, compared to what it was in 7.84.0.
Is it something known or a not previously noticed regression in 8.4.0?
Thanks,
Dmitry Karpov
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