Date: Fri, 15 Apr 2016 13:40:58 +0000 From: "jtl (Jonathan T. Looney)" <phabric-noreply@FreeBSD.org> To: freebsd-net@freebsd.org Subject: [Differential] [Commented On] D5872: tcp: Don't prematurely drop receiving-only connections Message-ID: <f02f2aac5db82463ddb6a822ea813ef5@localhost.localdomain> In-Reply-To: <differential-rev-PHID-DREV-5vu7wrfibtoing77xfvt-req@FreeBSD.org> References: <differential-rev-PHID-DREV-5vu7wrfibtoing77xfvt-req@FreeBSD.org>
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jtl added a comment. In https://reviews.freebsd.org/D5872#127063, @jtl wrote: > Doesn't tp->t_rxtshift get updated on a successful send? If not, I think that is what we should be fixing. Of course, tp->t_rxtshift doesn't get updated on a successful send. That's not the way this works. :-) Now that I've had more coffee... This probably amounts to the generic problem of: - When we send data, we should be setting the retransmit timer to make sure we retransmit. - When we are not sending data, we should be setting a different timer (DELACK, perhaps?) to make sure we send an ACK, when able. The key feature that makes the retransmit timer inappropriate for an ACK-only case is that it is only stopped when we receive input; however, in the ACK-only case, we really want to stop it as soon as we transmit a successful ACK. Of course, we could just drop the ACK and everything would "just work". But, it //probably// is still a good idea to try to re-transmit the ACK. REVISION DETAIL https://reviews.freebsd.org/D5872 EMAIL PREFERENCES https://reviews.freebsd.org/settings/panel/emailpreferences/ To: sepherosa_gmail.com, network, glebius, hiren, lstewart, adrian, delphij, decui_microsoft.com, honzhan_microsoft.com, howard0su_gmail.com, freebsd-net-list, transport, jtl Cc: jtl
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