From: Eric Dumazet <eric.dumazet@gmail.com>
To: Jesse Brandeburg <jesse.brandeburg@intel.com>
Cc: Frank Reppin <frank@undermydesk.org>,
netdev@vger.kernel.org,
Jeff Kirsher <jeffrey.t.kirsher@intel.com>,
e1000-devel@lists.sourceforge.net
Subject: Re: [PATCH net] e1000e: Change wthresh to 1 to avoid possible Tx stalls.
Date: Tue, 09 Oct 2012 23:02:07 +0200 [thread overview]
Message-ID: <1349816527.21172.5303.camel@edumazet-glaptop> (raw)
In-Reply-To: <20121009103629.0000569a@unknown>
On Tue, 2012-10-09 at 10:36 -0700, Jesse Brandeburg wrote:
> > > > Jesse did not share any performance numbers with me, I am sure he can
> > > > give some background tomorrow when he is back online.
> > > >
> > > > I am working on an alternative patch now and should have something to
> > > > share tomorrow.
> > > Please allow me to ask if there's any progess here?
> > >
> > > I've tried 3.5.4 a couple of days ago on a SuperMicro X8SIE-LN4 (82574L)
> > > and could still observe severe latency (up to 3000ms) spikes.
> > >
> > > Applying Hiroakis suggested patch did fix this for me as well.
> > > [please note as well that I didn't had this issue in any 3.4.x kernel
> > > before - so +1 for fixing the regression]
>
> I'm not sure what went wrong internally here that this hasn't been
> fixed, and I'm personally embarrassed. I am working on it until I have
> a patch/solution.
>
> currently am trying to reproduce the issue, am in some weird how to
> use BQL limbo, the lack of documentation on user usage of BQL is slowing
> me down.
>
BQL is blocking qdisc from delivering additional packet to TX as long as
previous packets were not completed. Not sure what you want to know
about BQL.
> Hints or clues (I'm trying to follow the repro steps mentioned in
> some related threads) are appreciated.
Problem is BQL depends on TX completion being done in a reasonable time.
It seems e1000e can hold an skb in TX ring for up to 3000ms (not
reasonable it seems)
Aggregation / coalescing is fine, as long as we dont hold a packet too
long, in case no other packet follows.
next prev parent reply other threads:[~2012-10-09 21:02 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-06-06 8:43 [PATCH net] e1000e: Change wthresh to 1 to avoid possible Tx stalls Hiroaki SHIMODA
2012-06-06 8:46 ` Jeff Kirsher
2012-06-06 8:50 ` Eric Dumazet
2012-06-07 0:59 ` Jeff Kirsher
2012-06-07 1:34 ` David Miller
2012-06-07 4:24 ` Eric Dumazet
2012-06-07 4:52 ` Jeff Kirsher
2012-06-07 5:03 ` Eric Dumazet
2012-10-09 0:25 ` Frank Reppin
2012-10-09 6:07 ` Eric Dumazet
2012-10-09 17:36 ` Jesse Brandeburg
2012-10-09 21:02 ` Eric Dumazet [this message]
2012-10-09 22:48 ` Andre Tomt
2012-10-10 1:25 ` Frank Reppin
-- strict thread matches above, loose matches on Subject: below --
2012-10-11 1:34 [PATCH NET] " Jesse Brandeburg
2012-10-11 3:00 ` David Miller
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