Re: Curl's network performance is slower than IDM.

Hongyi Zhao <hongyi.zhao_at_gmail.com> 于2020年6月19日周五 上午7:28写道：
>
> Daniel Stenberg <daniel_at_haxx.se> 于2020年6月19日周五 上午5:30写道：
> >
> > On Thu, 18 Jun 2020, Patrick Schlangen wrote:
> >
> > > Interestingly, IDM showed max 13.5 MB/s with an average total download time
> > > of 93 seconds, while curl showed max 12.0 MB/s and took 86 seconds for the
> > > same file on average. So actually curl was faster but displayed the lower
> > > max transfer rate.
> >
> > Thanks a lot Patrick for this simple and yet very revealing experiment!
>
> Another consideration came to my mind the speed computation method
> used in two tools. In detail:
>
> speed = downloaded_bytes / time_duration
>
> What I want to confirm is whether the different criterions for data
> package statistics are used for speed computation between IDM curl.
> Say, for downloaded_bytes, whether only take account in the payload,
> for time_duration, whether only take count in the real payload
> downloading duration?

For network data transmission, it's well known that there are some
extra control bits used in the data packets, and all we want is the
payload existed in the packets which will ultimately combined into the
downloaded file on our disk.

-- 
Hongyi Zhao <hongyi.zhao_at_gmail.com>
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