site_archiver@lists.apple.com Delivered-To: darwin-kernel@lists.apple.com Vincent Lubet writes:

Andrew,

This is an optimization that is simple missin in xnu -- thanks for bringing it to our attention.

Feel free to file an enhancement request at http:// bugreporter.apple.com/ to make sure this won't fall through the cracks.

Thanks Vince.. I've filed problem id 4919145. FWIW, it looks like the MSS clamping code was removed sometime between 10.2 and 10.3. I've never really understood why it helps so much. This isn't just my NIC that it helps for. See the thread starting at http://lists.freebsd.org/pipermail/freebsd-net/2004-January/002594.html where I actually proposed removing it, and found that it really did help! Do you have any intuition on why keeping things nicely aligned helps so much? Linux, on the same hardware, does not need to clamp the MTU, and easily maxes out the 10GbE link with far lower CPU utilization. Is the BSD stack just that much more sensitive to alignment? Drew _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-kernel mailing list (Darwin-kernel@lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-kernel/site_archiver%40lists.a... This email sent to site_archiver@lists.apple.com