Subject: Re: [netatalk-admins] Slow write performance on FreeBSD 2.2.5, 1.4b2
From: wesley.craig@umich.edu
Date: Tue Feb 24 1998 - 00:58:32 EST
> From: Bill Studenmund <skippy@macro.stanford.edu>
> To: Gary Teter <garyt@bulldogbeach.com>
> On Sat, 21 Feb 1998, Gary Teter wrote:
> > Someone suggested changing the definition of ddp_recvspace in
> > sys/netatalk/ddp_usrreq.c to a higher value, so I changed it to 50 * 600.
> Doh! That kills my favorite suggestion!
The normal value of ddp_recvspace, 10 * X, is enough for the eight
packets you'll get back from an ATP transaction, plus a couple more for
extra space. Each time this buffer is overflowed, there's a statistics
block that gets updated, ddps_nosockspace, which your favorite BSD unix
ought to return as output of netstat -s.
Generally speaking, you should never see this...
When your network performance is "really, really, slow", it's usually a
bad network. AppleTalk tolerates a *very* low network error rate. In
particular, write performance suffers because of the dual-ATP
transactions used to "turn" the 8 packet response into a write. If
you're getting, write, write, write, long ... pause ... write, write,
etc, then it's almost certainly a bad network.
The good news is that TCP is a non-sucking protocol, and can deal quite
well with lossy networks.
:wes
This archive was generated by hypermail 2b28 : Sat Dec 18 1999 - 16:31:09 EST