netdev - Re: [RFC PATCH] reuseport: compute the ehash only if needed

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Message-Id: <20171214.084157.738105599035562640.davem@davemloft.net>
Date:   Thu, 14 Dec 2017 08:41:57 -0500 (EST)
From:   David Miller <davem@...emloft.net>
To:     pabeni@...hat.com
Cc:     netdev@...r.kernel.org, kraig@...gle.com, edumazet@...gle.com
Subject: Re: [RFC PATCH] reuseport: compute the ehash only if needed

From: Paolo Abeni <pabeni@...hat.com>
Date: Thu, 14 Dec 2017 09:29:46 +0100

> I was unable to measure any performance regression for the hash based
> demultiplexing, and I think that the number of function calls is
> unchanged in such scenario (with vanilla kernel we have ehash() and
> reuseport_select_sock(), with the patched one __reuseport_get_info()
> and ehash()). 
> 
> I agree you are right about the additional stack usage introduced by
> this patch.
> 
> Overall I see we need something better than this.

Thanks for checking whether it's slower or not.  I wonder if x86-64
is putting the argument parts on the stack anyways...