From: Daniel Borkmann <dborkman@redhat.com>
To: Eric Dumazet <eric.dumazet@gmail.com>
Cc: davem@davemloft.net, netdev@vger.kernel.org,
netfilter-devel@vger.kernel.org
Subject: Re: [PATCH net-next 2/2] net: use reciprocal_divide instead of reimplementing it
Date: Tue, 03 Sep 2013 16:35:35 +0200 [thread overview]
Message-ID: <5225F3B7.2000202@redhat.com> (raw)
In-Reply-To: <1378216954.7360.25.camel@edumazet-glaptop>
On 09/03/2013 04:02 PM, Eric Dumazet wrote:
> On Tue, 2013-09-03 at 12:26 +0200, Daniel Borkmann wrote:
>> Replace these places with reciprocal_divide() inline function instead of
>> reimplementing it each time, thus it will become easier to read. We do not
>> need to explicitly include its header as it's pulled in from linux/net.h
>> anyway.
>
> Sure, (((u64) hash * qcount) >> 32) happens to be
> reciprocal_divide(hash, qcount) but the result depends on hash being
> well distributed in [0 .. ~0U] space.
>
> So 'reciprocal' and 'divide' do not accurately describe this exact
> operation.
>
> I suggest making the thing more descriptive.
>
> (And discussed on lkml btw)
Sure, we can do that. Then lets drop these two for now.
prev parent reply other threads:[~2013-09-03 14:35 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-09-03 10:26 [PATCH net-next 0/2] net_random_N, reciprocal_divide helper updates Daniel Borkmann
2013-09-03 10:26 ` [PATCH net-next 1/2] net: introduce generic net_random_N helper Daniel Borkmann
2013-09-03 11:00 ` Joe Perches
2013-09-03 11:40 ` Daniel Borkmann
2013-09-03 12:15 ` Joe Perches
2013-09-03 12:26 ` Daniel Borkmann
2013-09-03 12:41 ` Joe Perches
2013-09-03 13:59 ` Eric Dumazet
2013-09-03 10:26 ` [PATCH net-next 2/2] net: use reciprocal_divide instead of reimplementing it Daniel Borkmann
2013-09-03 14:02 ` Eric Dumazet
2013-09-03 14:35 ` Daniel Borkmann [this message]
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