netdev - Re: tcp bw in 2.6

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <4702A05D.6020509@hp.com>
Date:	Tue, 02 Oct 2007 12:47:41 -0700
From:	Rick Jones <rick.jones2@...com>
To:	Larry McVoy <lm@...mover.com>
Cc:	Linus Torvalds <torvalds@...ux-foundation.org>,
	davem@...emloft.net, wscott@...mover.com, netdev@...r.kernel.org
Subject: Re: tcp bw in 2.6

Larry McVoy wrote:
> On Tue, Oct 02, 2007 at 11:01:47AM -0700, Rick Jones wrote:
> 
>>has anyone already asked whether link-layer flow-control is enabled?
> 
> 
> I doubt it, the same test works fine in one direction and poorly in the other.
> Wouldn't the flow control squelch either way?

While I am often guilty of it, a wise old engineer tried to teach me that the 
proper spelling is ass-u-me :)  I wouldn't count on it hitting in both 
directions, depends on the specifics of the situation.

WRT the HP-UX ACK avoidance heuristic, the default HP-UX socket buffer/window is 
32768, and tcp_deferred_ack_max defaults to 22.  That isn't really all that good 
a combination - with a window of 32768 11 for the deferred ack would be better. 
  You could also go ahead and try it with a value of 2.  Or, bump the window 
size defaults - tcp_recv_hiwater_def and tcp_xmit_hiwater_def - to say 65535 or 
128K or something - or use the setsockopt() calls to effect that.

rick jones
-
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html