Re: Comparison of several congestion control algorithms
From: "David S. Miller" <davem@davemloft.net>
Date: 2005-06-02 23:53:41
From: "David S. Miller" <davem@davemloft.net>
Date: 2005-06-02 23:53:41
From: Baruch Even <redacted> Date: Fri, 03 Jun 2005 00:50:07 +0100
This is in part because of the start of the work that was based on 2.4 kernels and even as far as the 2.6.6 kernel which had disabled TSO once it saw SACKs. This made TSO unusable for our needs. AFAIK, the tests reported in that document used kernel 2.6.6.
Sure SACKs turn off TSO currently, but you'll have them enabled at the beginning until the first loss and this affects how fast the cwnd will grow. If you have e1000 cards, for example, you're getting TSO enabled by default. You really need to look into this, as it has a real and very non-trivial effect on all of the results you obtained.