From: Stephen Hemminger <stephen@networkplumber.org>
To: Jesper Dangaard Brouer <brouer@redhat.com>
Cc: cake@lists.bufferbloat.net
Subject: Re: [Cake] the meta problem of memory, locks, and multiple cpus
Date: Mon, 2 Nov 2015 16:55:32 -0800 [thread overview]
Message-ID: <20151102165532.2e714f77@xeon-e3> (raw)
In-Reply-To: <20151029120038.03f09749@redhat.com>
On Thu, 29 Oct 2015 12:00:38 +0100
Jesper Dangaard Brouer <brouer@redhat.com> wrote:
> On Thu, 29 Oct 2015 10:08:34 +0100
> Dave Taht <dave.taht@gmail.com> wrote:
>
> > The real problem A) that I wish we could solve at the qdisc layer
> >
> > is that we could size everything more appropriately if we actually
> > *knew* the physical link rate in many cases. It is *right there* in
> > the sys filesystem for ethernet devices, if only there was some way to
> > get at it, and get notifications if it changed.... or merely to know
> > the underlying operating range of the device at qdisc init time. It is
> > dumb to allow 50MB of memory for a 10mbit device just to make the
> > 10GigE folk happy.
>
> Well, do you really need to know the link rate? One of the lessons
> learned from codel (by Kathleen/Van) is that we should not trie to
> measure the link rate, but instead simply look at the time spend in
> queue.
Why not measure the egress rate like PIE?
It is right there in the same code.
Also many devices (like wifi) can't report real link rate.
next prev parent reply other threads:[~2015-11-03 0:55 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-10-29 9:08 Dave Taht
2015-10-29 11:00 ` Jesper Dangaard Brouer
2015-11-03 0:55 ` Stephen Hemminger [this message]
2015-11-03 1:32 ` Jonathan Morton
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