From: David Miller <davem@davemloft.net>
To: eric.dumazet@gmail.com
Cc: dave.taht@bufferbloat.net, nanditad@google.com,
netdev@vger.kernel.org, codel@lists.bufferbloat.net,
ycheng@google.com, shemminger@vyatta.com, mattmathis@google.com
Subject: Re: [Codel] [PATCH net-next] codel: use Newton method instead of sqrt() and divides
Date: Sat, 12 May 2012 16:45:13 -0400 (EDT) [thread overview]
Message-ID: <20120512.164513.1156706853054390966.davem@davemloft.net> (raw)
In-Reply-To: <1336855256.31653.1329.camel@edumazet-glaptop>
From: Eric Dumazet <eric.dumazet@gmail.com>
Date: Sat, 12 May 2012 22:40:56 +0200
> 24 bit of precision for the reciprocal value is more than enough (Van
> suggested 16 bits in fact), so we have actually room for 7 bits if
> needed.
Using a u16 would also work for me.
> By the way, gcc on x86 generates nice "and 0xfffffffe,%eax" instruction
> for (vars->rec_inv_sqrt << 1).
Yeah but what do stores of ->rec_inv_sqrt look like?
next prev parent reply other threads:[~2012-05-12 20:47 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-05-12 13:32 Eric Dumazet
2012-05-12 19:52 ` David Miller
2012-05-12 20:40 ` Eric Dumazet
2012-05-12 20:45 ` David Miller [this message]
2012-05-12 21:48 ` Eric Dumazet
2012-05-12 21:52 ` David Miller
2012-05-13 7:23 ` Eric Dumazet
2012-05-14 5:46 ` Andrew McGregor
2012-05-14 6:00 ` dave taht
2012-05-14 6:17 ` Eric Dumazet
2012-05-14 6:33 ` dave taht
2012-05-14 6:47 ` dave taht
2012-05-14 6:51 ` Roger Jørgensen
2012-05-14 8:23 ` Eric Dumazet
2012-05-14 8:50 ` dave taht
2012-05-14 9:03 ` Eric Dumazet
2012-05-14 11:34 ` Roger Jørgensen
2012-05-14 11:56 ` Eric Dumazet
2012-05-14 15:05 ` Dave Taht
2012-05-14 18:31 ` Roger Jørgensen
2012-05-14 22:33 ` David Miller
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