cvs commit: src/sys/netinet tcp_input.c tcp_output.c tcp_sack.c
tcp_var.h
Mohan Srinivasan
mohan_srinivasan at yahoo.com
Thu May 12 07:18:28 PDT 2005
Thanks.
I'll take a look at this.
mohan
--- Daniel Eriksson <daniel_k_eriksson at telia.com> wrote:
> Paul Saab wrote:
>
> > ps 2005-05-11 21:37:43 UTC
> >
> > FreeBSD src repository
> >
> > Modified files:
> > sys/netinet tcp_input.c tcp_output.c tcp_sack.c
> > tcp_var.h
> > Log:
> > When looking for the next hole to retransmit from the scoreboard,
> > or to compute the total retransmitted bytes in this sack recovery
> > episode, the scoreboard is traversed. While in sack recovery, this
> > traversal occurs on every call to tcp_output(), every dupack and
> > every partial ack. The scoreboard could potentially get quite large,
> > making this traversal expensive.
> >
> > This change optimizes this by storing hints (for the next hole to
> > retransmit and the total retransmitted bytes in this sack recovery
> > episode) reducing the complexity to find these values from O(n) to
> > constant time.
> >
> > The debug code that sanity checks the hints against the computed
> > value will be removed eventually.
>
> After upgrading one of my servers this morning (dual Athlon MP) I'm getting
> a fair amount of these on the console:
>
> tcp_sack_output: Computed sack hole not the same as cached value
>
> So far I have ~50 such lines in the log after ~3 hours of uptime. No users
> have reported any problems though.
>
> /Daniel Eriksson
>
>
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