From: Jean Tourrilhes <jean.tourrilhes@hpe.com>
To: Ilya Maximets <i.maximets@ovn.org>
Cc: Tonghao Zhang <xiangxia.m.yue@gmail.com>,
Pravin B Shelar <pshelar@ovn.org>,
"David S. Miller" <davem@davemloft.net>,
Jakub Kicinski <kuba@kernel.org>, Andy Zhou <azhou@ovn.org>,
Linux Kernel Network Developers <netdev@vger.kernel.org>,
LKML <linux-kernel@vger.kernel.org>,
ovs dev <dev@openvswitch.org>, William Tu <u9012063@gmail.com>,
Cong Wang <xiyou.wangcong@gmail.com>,
Davide Caratti <dcaratti@redhat.com>
Subject: Re: [PATCH net] openvswitch: meter: remove rate from the bucket size calculation
Date: Wed, 28 Apr 2021 09:31:24 -0700 [thread overview]
Message-ID: <20210428163124.GA28950@labs.hpe.com> (raw)
In-Reply-To: <04bd0073-6eb7-6747-a0b1-3c25cca7873a@ovn.org>
On Wed, Apr 28, 2021 at 01:22:12PM +0200, Ilya Maximets wrote:
>
> I didn't test it, but I looked at the implementation in
> net/sched/act_police.c and net/sched/sch_tbf.c, and they should work
> in a same way as this patch, i.e. it's a classic token bucket where
> burst is a burst and nothing else.
Actually, act_police.c and sch_tbf.c will behave completely
differently, even if they are both based on the token bucket
algorithm.
The reason is that sch_tbf.c is applied to a queue, and the
queue will smooth out traffic and avoid drops. The token bucket is
used to dequeue the queue, this is sometime called leaky bucket. I've
personally used sch_tbf.c with burst size barely bigger than the MTU,
and it works fine.
This is why I was suggesting to compare to act_police.c, which
does not have a queue to smooth out traffic and can only drop
packets.
I believe OVS meters are similar to policers, so that's why
they are suprising for people used to queues such as TBF and HTB.
Regards,
Jean
next prev parent reply other threads:[~2021-04-28 17:18 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-21 13:57 [PATCH net] openvswitch: meter: remove rate from the bucket size calculation Ilya Maximets
2021-04-23 20:10 ` patchwork-bot+netdevbpf
2021-04-28 6:24 ` Tonghao Zhang
2021-04-28 6:45 ` Jean Tourrilhes
2021-04-28 11:22 ` Ilya Maximets
2021-04-28 16:31 ` Jean Tourrilhes [this message]
2021-04-28 18:59 ` Ilya Maximets
2021-04-29 21:15 ` Ilya Maximets
2021-04-29 21:12 ` Ilya Maximets
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=20210428163124.GA28950@labs.hpe.com \
--to=jean.tourrilhes@hpe.com \
--cc=azhou@ovn.org \
--cc=davem@davemloft.net \
--cc=dcaratti@redhat.com \
--cc=dev@openvswitch.org \
--cc=i.maximets@ovn.org \
--cc=kuba@kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=netdev@vger.kernel.org \
--cc=pshelar@ovn.org \
--cc=u9012063@gmail.com \
--cc=xiangxia.m.yue@gmail.com \
--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).