MINOR: quic: More precise window update calculation
When in congestion avoidance state and when acknowledging an <acked> number bytes
we must increase the congestion window by at most one datagram (<path->mtu>)
by congestion window. So thanks to this patch we apply a ratio to the current
number of acked bytes : <acked> * <path->mtu> / <cwnd>.
So, when <cwnd> bytes are acked we precisely increment <cwnd> by <path->mtu>.
Furthermore we take into an account the number of remaining acknowledged bytes
each time we increment the window by <acked> storing their values in the algorithm
struct state (->remain_acked) so that it might be take into an account at the
next ACK event.
diff --git a/include/haproxy/quic_cc-t.h b/include/haproxy/quic_cc-t.h
index 78af6a5..95d9922 100644
--- a/include/haproxy/quic_cc-t.h
+++ b/include/haproxy/quic_cc-t.h
@@ -76,6 +76,7 @@
uint64_t cwnd;
uint64_t ssthresh;
uint64_t recovery_start_time;
+ uint64_t remain_acked;
} nr;
};
diff --git a/src/quic_cc_newreno.c b/src/quic_cc_newreno.c
index e15b302..3952910 100644
--- a/src/quic_cc_newreno.c
+++ b/src/quic_cc_newreno.c
@@ -35,6 +35,7 @@
cc->algo_state.nr.cwnd = path->cwnd;
cc->algo_state.nr.ssthresh = QUIC_CC_INFINITE_SSTHESH;
cc->algo_state.nr.recovery_start_time = 0;
+ cc->algo_state.nr.remain_acked = 0;
return 1;
}
@@ -95,17 +96,20 @@
path = container_of(cc, struct quic_path, cc);
switch (ev->type) {
case QUIC_CC_EVT_ACK:
+ {
+ uint64_t acked;
/* Do not increase the congestion window in recovery period. */
if (ev->ack.time_sent <= cc->algo_state.nr.recovery_start_time)
goto out;
- /* Increasing the congestion window by 1 maximum packet size by
- * congestion window.
+ /* Increasing the congestion window by (acked / cwnd)
*/
- cc->algo_state.nr.cwnd +=
- path->mtu * QUIC_MAX(1ULL, (unsigned long long)ev->ack.acked / cc->algo_state.nr.cwnd);
+ acked = ev->ack.acked * path->mtu + cc->algo_state.nr.remain_acked;
+ cc->algo_state.nr.remain_acked = acked % cc->algo_state.nr.cwnd;
+ cc->algo_state.nr.cwnd += acked / cc->algo_state.nr.cwnd;
path->cwnd = cc->algo_state.nr.cwnd;
break;
+ }
case QUIC_CC_EVT_LOSS:
/* Do not decrease the congestion window when already in recovery period. */