netdev - RE: [PATCH 6/7] mlx4_en: Adding rxhash support

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Date:	Tue, 18 Oct 2011 08:59:44 +0000
From:	Yevgeny Petrilin <yevgenyp@...lanox.co.il>
To:	Eric Dumazet <eric.dumazet@...il.com>
CC:	"davem@...emloft.net" <davem@...emloft.net>,
	"netdev@...r.kernel.org" <netdev@...r.kernel.org>
Subject: RE: [PATCH 6/7] mlx4_en: Adding rxhash support

> 
> What is the gain using random values ?
> 
> Usually, we tend to have same hardware in a single machine, or we use
> active-backup bonding mode, and an active slave flip can change rxhash
> values with litle effect, since this happens not often.
> 
> I really prefer not random values, because it allows to have replayable
> configurations : For a given tcp flow, the same rxhash value is given
> and same cpu target in RPS. Its way easier to tune your machine for some workloads.
> 

There is no gain in random values, 
I'll make the change to have static value for RSS function.

We might consider how to ensure consistency across the different drivers in this aspect.