From: Pengcheng Yang <yangpc@wangsu.com>
To: edumazet@google.com, ncardwell@google.com, davem@davemloft.net
Cc: netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
Pengcheng Yang <yangpc@wangsu.com>
Subject: [PATCH RESEND net-next v2 2/5] tcp: fix stretch ACK bugs in Scalable
Date: Mon, 16 Mar 2020 14:35:08 +0800 [thread overview]
Message-ID: <1584340511-9870-3-git-send-email-yangpc@wangsu.com> (raw)
In-Reply-To: <1584340511-9870-1-git-send-email-yangpc@wangsu.com>
Change Scalable to properly handle stretch ACKs in additive
increase mode by passing in the count of ACKed packets to
tcp_cong_avoid_ai().
In addition, because we are now precisely accounting for
stretch ACKs, including delayed ACKs, we can now change
TCP_SCALABLE_AI_CNT to 100.
Signed-off-by: Pengcheng Yang <yangpc@wangsu.com>
---
net/ipv4/tcp_scalable.c | 17 +++++++++--------
1 file changed, 9 insertions(+), 8 deletions(-)
diff --git a/net/ipv4/tcp_scalable.c b/net/ipv4/tcp_scalable.c
index 471571e..6cebf41 100644
--- a/net/ipv4/tcp_scalable.c
+++ b/net/ipv4/tcp_scalable.c
@@ -10,10 +10,9 @@
#include <net/tcp.h>
/* These factors derived from the recommended values in the aer:
- * .01 and and 7/8. We use 50 instead of 100 to account for
- * delayed ack.
+ * .01 and and 7/8.
*/
-#define TCP_SCALABLE_AI_CNT 50U
+#define TCP_SCALABLE_AI_CNT 100U
#define TCP_SCALABLE_MD_SCALE 3
static void tcp_scalable_cong_avoid(struct sock *sk, u32 ack, u32 acked)
@@ -23,11 +22,13 @@ static void tcp_scalable_cong_avoid(struct sock *sk, u32 ack, u32 acked)
if (!tcp_is_cwnd_limited(sk))
return;
- if (tcp_in_slow_start(tp))
- tcp_slow_start(tp, acked);
- else
- tcp_cong_avoid_ai(tp, min(tp->snd_cwnd, TCP_SCALABLE_AI_CNT),
- 1);
+ if (tcp_in_slow_start(tp)) {
+ acked = tcp_slow_start(tp, acked);
+ if (!acked)
+ return;
+ }
+ tcp_cong_avoid_ai(tp, min(tp->snd_cwnd, TCP_SCALABLE_AI_CNT),
+ acked);
}
static u32 tcp_scalable_ssthresh(struct sock *sk)
--
1.8.3.1
next prev parent reply other threads:[~2020-03-16 7:04 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-16 6:35 [PATCH RESEND net-next v2 0/5] tcp: fix stretch ACK bugs in congestion control modules Pengcheng Yang
2020-03-16 6:35 ` [PATCH RESEND net-next v2 1/5] tcp: fix stretch ACK bugs in BIC Pengcheng Yang
2020-03-16 21:19 ` Neal Cardwell
2020-03-16 6:35 ` Pengcheng Yang [this message]
2020-03-16 21:25 ` [PATCH RESEND net-next v2 2/5] tcp: fix stretch ACK bugs in Scalable Neal Cardwell
2020-03-16 6:35 ` [PATCH RESEND net-next v2 3/5] tcp: stretch ACK fixes in Veno prep Pengcheng Yang
2020-03-16 21:42 ` Neal Cardwell
2020-03-16 6:35 ` [PATCH RESEND net-next v2 4/5] tcp: fix stretch ACK bugs in Veno Pengcheng Yang
2020-03-16 21:46 ` Neal Cardwell
2020-03-16 6:35 ` [PATCH RESEND net-next v2 5/5] tcp: fix stretch ACK bugs in Yeah Pengcheng Yang
2020-03-17 1:27 ` [PATCH RESEND net-next v2 0/5] tcp: fix stretch ACK bugs in congestion control modules David Miller
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=1584340511-9870-3-git-send-email-yangpc@wangsu.com \
--to=yangpc@wangsu.com \
--cc=davem@davemloft.net \
--cc=edumazet@google.com \
--cc=linux-kernel@vger.kernel.org \
--cc=ncardwell@google.com \
--cc=netdev@vger.kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).