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-rw-r--r--net/dccp/ccids/Kconfig31
-rw-r--r--net/dccp/ccids/ccid3.c11
-rw-r--r--net/dccp/ccids/ccid3.h2
3 files changed, 6 insertions, 38 deletions
diff --git a/net/dccp/ccids/Kconfig b/net/dccp/ccids/Kconfig
index 8408398cd44e..0581143cb800 100644
--- a/net/dccp/ccids/Kconfig
+++ b/net/dccp/ccids/Kconfig
@@ -47,37 +47,6 @@ config IP_DCCP_CCID3_DEBUG
If in doubt, say N.
-config IP_DCCP_CCID3_RTO
- int "Use higher bound for nofeedback timer"
- default 100
- depends on IP_DCCP_CCID3 && EXPERIMENTAL
- ---help---
- Use higher lower bound for nofeedback timer expiration.
-
- The TFRC nofeedback timer normally expires after the maximum of 4
- RTTs and twice the current send interval (RFC 3448, 4.3). On LANs
- with a small RTT this can mean a high processing load and reduced
- performance, since then the nofeedback timer is triggered very
- frequently.
-
- This option enables to set a higher lower bound for the nofeedback
- value. Values in units of milliseconds can be set here.
-
- A value of 0 disables this feature by enforcing the value specified
- in RFC 3448. The following values have been suggested as bounds for
- experimental use:
- * 16-20ms to match the typical multimedia inter-frame interval
- * 100ms as a reasonable compromise [default]
- * 1000ms corresponds to the lower TCP RTO bound (RFC 2988, 2.4)
-
- The default of 100ms is a compromise between a large value for
- efficient DCCP implementations, and a small value to avoid disrupting
- the network in times of congestion.
-
- The purpose of the nofeedback timer is to slow DCCP down when there
- is serious network congestion: experimenting with larger values should
- therefore not be performed on WANs.
-
config IP_DCCP_TFRC_LIB
def_bool y if IP_DCCP_CCID3
diff --git a/net/dccp/ccids/ccid3.c b/net/dccp/ccids/ccid3.c
index 4340672a817c..278e17069322 100644
--- a/net/dccp/ccids/ccid3.c
+++ b/net/dccp/ccids/ccid3.c
@@ -460,13 +460,12 @@ done_computing_x:
sk->sk_write_space(sk);
/*
- * Update timeout interval for the nofeedback timer.
- * We use a configuration option to increase the lower bound.
- * This can help avoid triggering the nofeedback timer too
- * often ('spinning') on LANs with small RTTs.
+ * Update timeout interval for the nofeedback timer. In order to control
+ * rate halving on networks with very low RTTs (<= 1 ms), use per-route
+ * tunable RTAX_RTO_MIN value as the lower bound.
*/
- hc->tx_t_rto = max_t(u32, 4 * hc->tx_rtt, (CONFIG_IP_DCCP_CCID3_RTO *
- (USEC_PER_SEC / 1000)));
+ hc->tx_t_rto = max_t(u32, 4 * hc->tx_rtt,
+ USEC_PER_SEC/HZ * tcp_rto_min(sk));
/*
* Schedule no feedback timer to expire in
* max(t_RTO, 2 * s/X) = max(t_RTO, 2 * t_ipi)
diff --git a/net/dccp/ccids/ccid3.h b/net/dccp/ccids/ccid3.h
index b1864243be07..b7e569c22f36 100644
--- a/net/dccp/ccids/ccid3.h
+++ b/net/dccp/ccids/ccid3.h
@@ -42,7 +42,7 @@
#include "lib/tfrc.h"
#include "../ccid.h"
-/* Two seconds as per RFC 3448 4.2 */
+/* Two seconds as per RFC 5348, 4.2 */
#define TFRC_INITIAL_TIMEOUT (2 * USEC_PER_SEC)
/* In usecs - half the scheduling granularity as per RFC3448 4.6 */
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