Comment by andreyf

So it would appear, according to the man pages: http://linux.die.net/man/7/tcp

In quickack mode, acks are sent immediately, rather than delayed if needed in accordance to normal TCP operation.

So "normal TCP operation" is to delay ACKs "if needed". Not sure if "needed" is the right word to use, but whatever.

Looks like RHEL has a system-wide fix: https://access.redhat.com/documentation/en-US/Red_Hat_Enterp...