From: Eliezer Tamir <eliezer.tamir@linux.intel.com>
To: Or Gerlitz <or.gerlitz@gmail.com>
Cc: Willem de Bruijn <willemb@google.com>,
e1000-devel@lists.sourceforge.net, netdev@vger.kernel.org,
HPA <hpa@zytor.com>,
Jesse Brandeburg <jesse.brandeburg@intel.com>,
Alex Rosenbaum <alexr@mellanox.com>,
linux-kernel@vger.kernel.org,
Eliezer Tamir <eliezer@tamir.org.il>,
Andi Kleen <andi@firstfloor.org>,
Eric Dumazet <erdnetdev@gmail.com>,
Eilon Greenstien <eilong@broadcom.com>,
David Miller <davem@davemloft.net>
Subject: Re: [PATCH v6 net-next 2/5] net: implement support for low latency socket polling
Date: Thu, 30 May 2013 09:04:18 +0300 [thread overview]
Message-ID: <51A6EBE2.6050108@linux.intel.com> (raw)
In-Reply-To: <CAJZOPZLC=drE9dTpnj2hLdDmfnL+T4gOU1j1xYwbmYy-J9HaAQ@mail.gmail.com>
On 29/05/2013 21:52, Or Gerlitz wrote:
> Eliezer Tamir <eliezer.tamir@linux.intel.com> wrote:
>> Or Gerlitz wrote:
>
>>> Unlike with TCP sockets, UDP sockets may receive packets from multiple
>>> sources and hence the receiving context may be steered to be executed
>>> on different cores through RSS or other Flow-Steering HW mechanisms
>>> which could mean different napi contexts for the same socket, is that
>>> a problem here? what's the severity?
>
>> Nothing will break if you poll on the wrong queue.
>> Your data will come through normal NAPI processing of the right queue.
>
> Can you elaborate a little further, why you call this "wrong" and "right"?
Right == the queue the packets arrive on.
Wrong == any other queue.
BTW, if you have an application that receives UDP data to an unbound
socket, wouldn't it be better in any case to steer all of the incoming
packets for this UDP socket to a single queue disregarding the source
address? (Can't your hardware do that?)
The general approach is that userspace needs to make sure that threads,
connections and IRQs are bound to the right CPUs.
-Eliezer
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next prev parent reply other threads:[~2013-05-30 6:04 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-05-29 6:39 [PATCH v6 net-next 0/5] net: low latency Ethernet device polling Eliezer Tamir
2013-05-29 6:39 ` [PATCH v6 net-next 1/5] net: add napi_id and hash Eliezer Tamir
2013-05-29 12:56 ` Eric Dumazet
2013-05-29 13:09 ` David Laight
2013-05-29 13:43 ` Eric Dumazet
2013-05-29 15:04 ` Eliezer Tamir
2013-05-29 20:09 ` Ben Hutchings
2013-05-30 6:51 ` Eliezer Tamir
2013-05-29 6:39 ` [PATCH v6 net-next 2/5] net: implement support for low latency socket polling Eliezer Tamir
2013-05-29 13:37 ` Eric Dumazet
2013-05-29 13:42 ` David Laight
2013-05-29 13:48 ` Eric Dumazet
2013-05-29 14:01 ` Eliezer Tamir
2013-05-29 14:20 ` yaniv saar
2013-05-29 15:01 ` Eliezer Tamir
2013-05-29 14:14 ` Or Gerlitz
2013-05-29 14:40 ` yaniv saar
2013-05-29 14:59 ` Eliezer Tamir
2013-05-29 18:52 ` Or Gerlitz
2013-05-29 19:08 ` Eric Dumazet
2013-05-30 5:58 ` Eliezer Tamir
2013-05-30 6:04 ` Eliezer Tamir [this message]
2013-05-29 20:20 ` Ben Hutchings
2013-05-29 6:39 ` [PATCH v6 net-next 3/5] tcp: add TCP support for low latency receive poll Eliezer Tamir
2013-05-29 13:38 ` Eric Dumazet
2013-05-29 6:39 ` [PATCH v6 net-next 4/5] ixgbe: Add support for ndo_ll_poll Eliezer Tamir
2013-05-29 6:40 ` [PATCH v6 net-next 5/5] ixgbe: add extra stats " Eliezer Tamir
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