Messages in this thread | | | Date | Thu, 18 Jan 2001 10:24:48 -0800 | From | Rick Jones <> | Subject | Re: [Fwd: [Fwd: Is sendfile all that sexy? (fwd)]] |
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Ingo Molnar wrote: > > On Wed, 17 Jan 2001, Rick Jones wrote: > > > i'd heard interesting generalities but no specifics. for instance, > > when the send is small, does TCP wait exclusively for the app to > > flush, or is there an "if all else fails" sort of timer running? > > yes there is a per-socket timer for this. According to RFC 1122 a TCP > stack 'MUST NOT' buffer app-sent TCP data indefinitely if the PSH bit > cannot be explicitly set by a SEND operation. Was this a trick question? > :-)
Nope, not a trick question. The nagle heuristic means that small sends will not wait indefinitely since sending the first small bit of data starts the retransmission timer as a course of normal processing. So, I am not in the habit of thinking about a "clear the buffer" timer being set when a small send takes place but no transmit happens.
rick jones
btw, as I'm currently on linux-kernel, no need to cc me :) -- ftp://ftp.cup.hp.com/dist/networking/misc/rachel/ these opinions are mine, all mine; HP might not want them anyway... :) feel free to email, OR post, but please do NOT do BOTH... my email address is raj in the cup.hp.com domain... - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org Please read the FAQ at http://www.tux.org/lkml/
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