netdev - Re: [PATCH net-next 1/3] net:dsa:mv88e6xxx: use hashtable to store multicast entries

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Date:   Mon, 12 Dec 2016 08:37:50 -0800
From:   Florian Fainelli <f.fainelli@...il.com>
To:     Volodymyr Bendiuga <valdr.linuxnext@...il.com>,
        Vivien Didelot <vivien.didelot@...oirfairelinux.com>
Cc:     Volodymyr Bendiuga <volodymyr.bendiuga@...il.com>, andrew@...n.ch,
        netdev@...r.kernel.org,
        Volodymyr Bendiuga <volodymyr.bendiuga@...termo.se>
Subject: Re: [PATCH net-next 1/3] net:dsa:mv88e6xxx: use hashtable to store
 multicast entries

On 12/12/2016 07:22 AM, Volodymyr Bendiuga wrote:
> Hi,
> 
> I apologise for incorrectly formatted patch, I will fix and resend it.
> The problem with the ATU right now is that it is too slow when inserting
> entries.
> When the OS boots up, it might insert some multicast entries into the
> atu (if
> they are preconfigured by user). I run a test with 10 mc entries being
> configured for
> each port (13 ports), and it took 15 seconds, which made system quite
> slow on responding to
> other commands, as it has been inserting mc entries. The implementation
> with hashtable
> made insert command for 13 ports and 10 entries per port about 700 msec
> long.


Just wondering how do you achieve such speed up? What part of using a
hashtable allows you not to write down all 10 MC entries across the
ports? I would assume that the number of MDIO (is that the bus you are
using here?) operations would be identical.

Seeing such a change makes me wonder if we should not try to push some
of this hashtable abstraction (provided that we agree we want it) at a
higher layer, like net/dsa/slave.c?

Thanks!
-- 
Florian