On Wed, Aug 17, 2016 at 12:05:22PM +0300, Jouni Malinen wrote: > I had not realized this previously due to the test case passing, but the > same retransmit SYN case was happening with older kernels, it just was > done a tiny bit faster to escape that 1.0 second timeout limit.. That > about 1.03 sec value after this kernel commit is 1.0 sec before this > kernel commit. In other words, something in this specific kernel commit > seems to add about 0.03 sec delay to the TCP SYN retransmission.
Yes, and this 3% increase in the timeout expiration interval is an expected result using the new timer wheel. See the large comment at the top of kernel/time/timer.c and the lkml discussion about this series. > That > said, I realize that this is quite unlikely timeout to use for connect() > in real world and as such, it looks simply as a side effect of a test > case that was using way too close timing requirement in the first place. Right, and user space should not rely on the exact timing of TCP SYN re-transmission! Thanks, Richard
