From: Eric Dumazet <eric.dumazet@gmail.com>
To: "John A. Sullivan III" <jsullivan@opensourcedevel.com>
Cc: netdev@vger.kernel.org
Subject: Re: Latency difference between fifo and pfifo_fast
Date: Tue, 06 Dec 2011 07:29:02 +0100 [thread overview]
Message-ID: <1323152942.2467.16.camel@edumazet-laptop> (raw)
In-Reply-To: <1323151377.2467.13.camel@edumazet-laptop>
Le mardi 06 décembre 2011 à 07:02 +0100, Eric Dumazet a écrit :
> Le lundi 05 décembre 2011 à 23:10 -0500, John A. Sullivan III a écrit :
> > Hello, all. We are trying to minimize latency on our iSCSI SAN. The
> > network is entirely dedicated to the iSCSI traffic. Since all the
> > traffic is the same, would it make sense to change the qdisc for that
> > interface to fifo from the default pfifo_fast or is the latency
> > difference between the two completely negligible? Thanks - John
>
> A very small difference indeed. How many packets per second are
> expected ? What kind of NIC are you using ?
>
To really remove a possible source of latency, you could remove qdisc
layer...
ifconfig eth2 txqueuelen 0
tc qdisc add dev eth2 root pfifo
tc qdisc del dev eth2 root
next prev parent reply other threads:[~2011-12-06 6:29 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <8f05fdb0-6e4c-4adf-b8d1-bd67a0dc114f@jasiiieee>
2011-12-06 4:10 ` Latency difference between fifo and pfifo_fast John A. Sullivan III
2011-12-06 6:02 ` Eric Dumazet
2011-12-06 6:29 ` Eric Dumazet [this message]
2011-12-06 8:39 ` John A. Sullivan III
2011-12-06 8:51 ` Eric Dumazet
2011-12-06 18:20 ` Rick Jones
2011-12-06 18:39 ` Dave Taht
2011-12-06 19:44 ` John A. Sullivan III
2011-12-07 13:04 ` Eric Dumazet
2011-12-07 13:27 ` Dave Taht
2011-12-07 14:08 ` David Laight
2011-12-08 0:05 ` John A. Sullivan III
2011-12-07 23:27 ` Stephen Hemminger
2011-12-08 0:34 ` John A. Sullivan III
2011-12-07 23:49 ` Stephen Hemminger
2011-12-08 3:20 ` John A. Sullivan III
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