From: Jamal Hadi Salim <jhs@mojatatu.com>
To: Edward Cree <ecree@solarflare.com>, netdev <netdev@vger.kernel.org>
Cc: Jiri Pirko <jiri@resnulli.us>, Cong Wang <xiyou.wangcong@gmail.com>
Subject: Re: TC stats / hw offload question
Date: Tue, 5 Feb 2019 21:20:29 -0500 [thread overview]
Message-ID: <4cb765dd-453f-3139-bce6-6e0b31167aec@mojatatu.com> (raw)
In-Reply-To: <26f0cfc9-3bef-8579-72cc-aa6c5ccecd43@solarflare.com>
On 2019-02-05 2:41 p.m., Edward Cree wrote:
> Regarding TC_CLSFLOWER_STATS, when a filter rule modifies the length of
> the packet, e.g. by adding a VLAN or encap header, should the bytes
> counter count the length of the packet _before_ edits (i.e. as seen by
> the match), or the length after edits?
Classifier stats - when they exist - should be on
"classified" packets. i.e before edits.
Edits are typically done by actions. And even then we dont
have counters which indicate the post edit resizing.
> If the latter, what is the
> correct behaviour when (say) a packet is mirrored as-is but also
> redirected with encapsulation?
It is that ambiguity that make it hard to maintain a single
counter for post-edit size. packet and byte counts are on
"entry".
> The fact that the stats live in the struct tc_action suggests a per-
> action connection that would imply post-edit length,
The classifiers dont mod the packets. The actions do. And they
maintain stats on the size on "entry" i.e pre-edit.
> but then in
> tcf_exts_dump_stats() we only look at the first action, which seems to
> imply we really want the pre-edit length.
> I can't find any kind of doc or spec defining what behaviour is required.
>
Each action keeps its own counters. If you did something like:
tc match using flower blah \
action vlan push tag ... \
action redirect to egress of eth0
And you submited a packet of size x bytes,
then the "match" would record x bytes.
the "vlan action" would record x bytes.
the "redirect" would record size x+vlaninfo bytes
the egress of eth0 would recorr x+vlaninfo bytes
cheers,
jamal
> -Ed
>
next prev parent reply other threads:[~2019-02-06 2:20 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-02-05 19:41 TC stats / hw offload question Edward Cree
2019-02-06 2:20 ` Jamal Hadi Salim [this message]
2019-02-08 10:26 ` Edward Cree
2019-02-09 17:39 ` Jamal Hadi Salim
2019-02-11 11:44 ` Edward Cree
2019-02-14 12:39 ` Jamal Hadi Salim
2019-02-14 15:17 ` Andy Gospodarek
2019-02-18 18:56 ` Edward Cree
2019-02-18 19:37 ` Edward Cree
2019-04-24 14:05 ` Edward Cree
2019-04-24 14:11 ` Pablo Neira Ayuso
2019-04-24 15:03 ` Edward Cree
2019-04-25 13:23 ` Edward Cree
2019-04-25 22:33 ` Pablo Neira Ayuso
2019-04-26 12:13 ` Edward Cree
2019-04-26 12:42 ` Jamal Hadi Salim
2019-04-26 18:49 ` Pablo Neira Ayuso
2019-04-29 14:11 ` Edward Cree
2019-04-29 15:21 ` Pablo Neira Ayuso
2019-04-29 16:25 ` Edward Cree
2019-04-29 19:14 ` Pablo Neira Ayuso
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=4cb765dd-453f-3139-bce6-6e0b31167aec@mojatatu.com \
--to=jhs@mojatatu.com \
--cc=ecree@solarflare.com \
--cc=jiri@resnulli.us \
--cc=netdev@vger.kernel.org \
--cc=xiyou.wangcong@gmail.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 a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).