From: Ben Hutchings <bhutchings@solarflare.com>
To: Jon Zhou <Jon.Zhou@jdsu.com>
Cc: "netdev@vger.kernel.org" <netdev@vger.kernel.org>
Subject: Re: why all packets have same queue no when rps enabled?
Date: Tue, 22 Feb 2011 12:45:56 +0000 [thread overview]
Message-ID: <1298378756.2211.478.camel@localhost> (raw)
In-Reply-To: <4A6A2125329CFD4D8CC40C9E8ABCAB9F24D3DE6D0C@MILEXCH2.ds.jdsu.net>
On Mon, 2011-02-21 at 20:07 -0800, Jon Zhou wrote:
> Hi
>
> I expect each incoming packet will have a different queue no. when I
> enabled RPS on kernel 2.6.36.4
[...]
> Looks almost all packets fall at same queue?
> Will RPS allocate queue no for each packet? and what hash algorithm
> rps used? (is it Toeplitz hash algorithm?)
The queue number identifies a hardware queue. RPS therefore does not
update this number when queueing packets for processing on other CPUs.
If the hardware/driver provides a receive hash (probably Toeplitz) then
this is used for RPS. Otherwise a much cheaper hash is used.
Ben.
--
Ben Hutchings, Senior Software Engineer, Solarflare Communications
Not speaking for my employer; that's the marketing department's job.
They asked us to note that Solarflare product names are trademarked.
next prev parent reply other threads:[~2011-02-22 12:46 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-02-22 4:07 why all packets have same queue no when rps enabled? Jon Zhou
2011-02-22 5:41 ` Eric Dumazet
2011-02-22 5:56 ` Jon Zhou
2011-02-22 6:13 ` Eric Dumazet
2011-02-22 12:45 ` Ben Hutchings [this message]
2011-02-22 13:01 ` Eric Dumazet
2011-02-22 13:09 ` Ben Hutchings
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