All of lore.kernel.org
 help / color / mirror / Atom feed
From: Sowmini Varadhan <sowmini.varadhan@oracle.com>
To: Tom Herbert <tom@herbertland.com>
Cc: "David S. Miller" <davem@davemloft.net>,
	Linux Kernel Network Developers <netdev@vger.kernel.org>,
	Kernel Team <kernel-team@fb.com>
Subject: Re: [PATCH net] net: Allow flow dissector to handle non 4-byte aligned headers
Date: Wed, 3 Feb 2016 12:31:25 -0500	[thread overview]
Message-ID: <20160203173125.GA14627@oracle.com> (raw)
In-Reply-To: <CALx6S34MGwp2m=QmfQ36tWnaWbFXvMG63sj7Nz1KgMtegxn-2A@mail.gmail.com>

On (02/03/16 09:07), Tom Herbert wrote:
> > Kernel unaligned access at TPC[9150dc] ipv4_neigh_lookup+0x38/0x170
> 
> Sowmini,
> 
> This doesn't look like a hard crash to me. Instead of trying to fix
> all the alignment issues for Sparc, can we just take the trap, fix up
> the load, and continue without any further fuss? Performance might
> suffer, but it doesn't seem like the bad alignments are happening in
> critical paths.
> 

None of these things is a hard crash, but they are 

(a) quite noisy 
(b) I'm able to generate alignment falls merely by configuring
    tunnels, and it gets worse when I disable RSS and use RFS/RPS
    instead. So "critical path" might need some definition.
(c) a perf risk for other platforms as well, even when they dont
    complain noisily about it.

--Sowmini

  reply	other threads:[~2016-02-03 17:31 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-01-31 21:37 [PATCH net] net: Allow flow dissector to handle non 4-byte aligned headers Tom Herbert
2016-01-31 21:47 ` kbuild test robot
2016-01-31 22:06 ` Florian Westphal
2016-02-01  0:24 ` Eric Dumazet
2016-02-01  0:39   ` Florian Fainelli
2016-02-01 15:20     ` Nicolas Dichtel
2016-02-01 16:01       ` Sowmini Varadhan
2016-02-01  0:43   ` Sowmini Varadhan
2016-02-01 12:32 ` Sergei Shtylyov
2016-02-02  0:31 ` Sowmini Varadhan
2016-02-02  0:46   ` Tom Herbert
2016-02-02  3:56   ` Alexander Duyck
2016-02-02 13:41     ` Hannes Frederic Sowa
2016-02-02 18:35     ` Sowmini Varadhan
2016-02-03 17:07   ` Tom Herbert
2016-02-03 17:31     ` Sowmini Varadhan [this message]
2016-02-03 17:51       ` Tom Herbert
2016-02-03 17:59         ` Sowmini Varadhan

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20160203173125.GA14627@oracle.com \
    --to=sowmini.varadhan@oracle.com \
    --cc=davem@davemloft.net \
    --cc=kernel-team@fb.com \
    --cc=netdev@vger.kernel.org \
    --cc=tom@herbertland.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.