When a download size is known and rate limiting is in effect, adjust the
duration of each measurement step and its rate for maximum precision.
Since it is unpredictable how long the last bytes of a download will
take, download speed can be thrown off if the "last bytes" are a
significant amount of the total download. Make the "last bytes" small in
comparision to the rest and "stretch" the rate limit intervals to
accommodate the difference.
Fix ngtcp2 receive data acknowldgements to be based on a local window
size tracking. This allows window updates controlled by rate limits.
Fix ratelimit wait time calculation to accomodate negative tokens.
h3 rate limit, update timeers
Make download rate limits work correctly in ngtcp2. Fix multi handling
of rate limits to set a timer for when limits will update again.
Without running the transfer on limit updates, protocols like h2/h3 may
stall if the server does not send due to stream windows being too small.
scorecard: measure download speedlimits
When running scorecard with --limit-rate=n, show the reported download
speed averages plus percentage deviation from the limit.
Closes#20228
Use `data->progress.now` as the timestamp of proecssing a transfer.
Update it on significant events and refrain from calling `curlx_now()`
in many places.
The problem this addresses is
a) calling curlx_now() has costs, depending on platform. Calling it
every time results in 25% increase `./runtest` duration on macOS.
b) we used to pass a `struct curltime *` around to save on calls, but
when some method directly use `curx_now()` and some use the passed
pointer, the transfer experienes non-linear time. This results in
timeline checks to report events in the wrong order.
By keeping a timestamp in the easy handle and updating it there, no
longer invoking `curlx_now()` in the "lower" methods, the transfer
can observer a steady clock progression.
Add documentation in docs/internals/TIME-KEEPING.md
Reported-by: Viktor Szakats
Fixes#19935Closes#19961
Description of how this works in `docs/internal/RATELIMITS.ms`.
Notable implementation changes:
- KEEP_SEND_PAUSE/KEEP_SEND_HOLD and KEEP_RECV_PAUSE/KEEP_RECV_HOLD
no longer exist. Pausing is down via blocked the new rlimits.
- KEEP_SEND_TIMED no longer exists. Pausing "100-continue" transfers
is done in the new `Curl_http_perform_pollset()` method.
- HTTP/2 rate limiting implemented via window updates. When
transfer initiaiting connection has a ratelimit, adjust the
initial window size
- HTTP/3 ngtcp2 rate limitin implemnented via ack updates
- HTTP/3 quiche does not seem to support this via its API
- the default progress-meter has been improved for accuracy
in "current speed" results.
pytest speed tests have been improved.
Closes#19384
