From: Rick Jones <rick.jones2@hp.com>
To: Anatoly Sivov <mm05@mail.ru>
Cc: Eric Dumazet <eric.dumazet@gmail.com>, netdev@vger.kernel.org
Subject: Re: why does skb->tstamp use getnstimeofday?
Date: Mon, 16 Jan 2012 14:05:21 -0800 [thread overview]
Message-ID: <4F149F21.70400@hp.com> (raw)
In-Reply-To: <op.v74z14g2fzo5me@stalin>
On 01/15/2012 09:55 AM, Anatoly Sivov wrote:
> I missed that field tstamp is used for things other than RTT and can be
> even user-spaced with SO_TIMESTAMP.
> However, timekeeper speed up/slow down (due to ntp) can seriously affect
> some congestion avoidance algorithm quality, I guess.
> Am I wrong?
Good question - not sure if we will see anything, but the upcoming
leap-second might be interesting to watch - though I think contemporary
NTP addresses that by a big slew rather than a step adjust. Of course
it can step-adjust the time on the system, but 99 times out of 10 (*)
that will be just at system start-up, when there probably will not be
all that many congestion controlled connections active. Of course, who
knows what that 100th out of 10 times will do.
rick jones
* 99 times out of 10 is an expression which if I recall correctly was
coined or at least repeated by a high-school sports coach to mean
"virtually all of the time"
prev parent reply other threads:[~2012-01-16 22:05 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-01-15 15:11 why does skb->tstamp use getnstimeofday? Anatoly Sivov
2012-01-15 16:42 ` Eric Dumazet
2012-01-15 17:55 ` Anatoly Sivov
2012-01-15 18:00 ` Anatoly Sivov
2012-01-15 18:56 ` Eric Dumazet
2012-01-15 19:55 ` Anatoly Sivov
2012-01-16 22:05 ` Rick Jones [this message]
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