The Tail Loss Probe RFC specifies that the PTO value should be set to max(2 * SRTT, 10ms), where SRTT is the smoothed round-trip time.
The PTO value is converted to jiffies, so the timer might expire prematurely. This is especially problematic on systems in which HZ=100. To work around this issue, increase the number of jiffies by one, ensuring that the timeout won't expire in less than 10ms. Signed-off-by: Ido Yariv <idox.ya...@intel.com> --- net/ipv4/tcp_output.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c index 534e5fd..6f57d3d 100644 --- a/net/ipv4/tcp_output.c +++ b/net/ipv4/tcp_output.c @@ -2207,7 +2207,7 @@ bool tcp_schedule_loss_probe(struct sock *sk) if (tp->packets_out == 1) timeout = max_t(u32, timeout, (rtt + (rtt >> 1) + TCP_DELACK_MAX)); - timeout = max_t(u32, timeout, msecs_to_jiffies(10)); + timeout = max_t(u32, timeout, msecs_to_jiffies(10) + 1); /* If RTO is shorter, just schedule TLP in its place. */ tlp_time_stamp = tcp_time_stamp + timeout; -- 2.1.0 -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html