From: Alexander Duyck <alexander.h.duyck@intel.com>
To: Tom Herbert <therbert@google.com>
Cc: "netdev@vger.kernel.org" <netdev@vger.kernel.org>
Subject: Re: [RFC PATCH 0/3] Simplified 16 bit Toeplitz hash algorithm
Date: Mon, 03 Jan 2011 11:00:42 -0800 [thread overview]
Message-ID: <4D221CDA.4000104@intel.com> (raw)
In-Reply-To: <AANLkTiki5ZePtdj4ni2++z1KvHOttev1ZciaV-bRFbWA@mail.gmail.com>
On 1/3/2011 10:47 AM, Tom Herbert wrote:
> I'm not sure why this would be needed. What is the a advantage in
> making the TX and RX queues match?
>
If the application is affinitized and you are working with RX/TX pairs
as we have in ixgbe then you can be certain that your buffers are
staying in the same NUMA node or CPU as the application. Having them on
different NUMA nodes can hurt performance for either TX or RX.
The other advantage was that I didn't have to bother with trying to
reorder the source and destination values when computing an RX hash or a
TX hash. I can just call the same function and regardless of direction
I would get the same hash. That way I could be guaranteed in a routing
test that if I was using the RX hash to determine the TX queue that the
queue number shouldn't change.
I believe the same thing is being accomplished in RPS/TPS via a test for
the values and swapping them if source is greater than destination.
Thanks,
Alex
next prev parent reply other threads:[~2011-01-03 19:01 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-12-18 1:00 [RFC PATCH 0/3] Simplified 16 bit Toeplitz hash algorithm Alexander Duyck
2010-12-18 1:00 ` [RFC PATCH 1/3] net: add simplified 16 bit Toeplitz hash function for transmit side hashing Alexander Duyck
2010-12-18 1:00 ` [RFC PATCH 2/3] ixgbe: example of how to update ixgbe to make use of in-kernel Toeplitz hash Alexander Duyck
2010-12-18 1:00 ` [RFC PATCH 3/3] igb: example of how to update igb to make use of in-kernel Toeplitz hashing Alexander Duyck
2010-12-18 5:09 ` David Miller
2010-12-18 6:53 ` Alexander Duyck
2010-12-18 6:59 ` David Miller
2011-01-03 18:47 ` [RFC PATCH 0/3] Simplified 16 bit Toeplitz hash algorithm Tom Herbert
2011-01-03 19:00 ` Alexander Duyck [this message]
2011-01-03 19:02 ` David Miller
2011-01-03 19:30 ` Ben Hutchings
2011-01-03 19:52 ` Alexander Duyck
2011-01-03 19:54 ` David Miller
2011-01-03 20:15 ` Ben Hutchings
2011-01-03 21:45 ` Alexander Duyck
2011-01-04 3:25 ` Tom Herbert
2011-01-04 15:43 ` Ben Hutchings
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