HomeFreeBSD

Don't zero out srtt after excess retransmits

Description

Don't zero out srtt after excess retransmits

If the TCP stack has retransmitted more than 1/4 of the total
number of retransmits before a connection drop, it decides that
its current RTT estimate is hopelessly out of date and decides
to recalculate it from scratch starting with the next ACK.

Unfortunately, it implements this by zeroing out the current RTT
estimate. Drop this hack entirely, as it makes it significantly more
difficult to debug connection issues. Instead check for excessive
retransmits at the point where srtt is updated from an ACK being
received. If we've exceeded 1/4 of the maximum retransmits,
discard the previous srtt estimate and replace it with the latest
rtt measurement.

Differential Revision: https://reviews.freebsd.org/D9519
Reviewed by: gnn
Sponsored by: Dell EMC Isilon

Details

Committed
rstoneFeb 11 2017, 5:05 PM
Reviewer
gnn
Differential Revision
D9519: Don't zero out srtt after excess retransmits
Parents
rS313645: loader: implement MEDIA_FILEPATH_DP support in efipart
Branches
Unknown
Tags
Unknown