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From: Eric Dumazet <eric.dumazet@gmail.com>
To: David Miller <davem@davemloft.net>
Cc: netdev@vger.kernel.org, aduyck@mirantis.com
Subject: Re: [RFC] net: remove busylock
Date: Thu, 19 May 2016 11:44:10 -0700	[thread overview]
Message-ID: <1463683450.18194.220.camel@edumazet-glaptop3.roam.corp.google.com> (raw)
In-Reply-To: <20160519.111208.1949769629804288508.davem@davemloft.net>

On Thu, 2016-05-19 at 11:12 -0700, David Miller wrote:
> From: Eric Dumazet <eric.dumazet@gmail.com>
> Date: Thu, 19 May 2016 10:08:36 -0700
> 
> > busylock was added at the time we had expensive ticket spinlocks
> > 
> > (commit 79640a4ca6955e3ebdb7038508fa7a0cd7fa5527 ("net: add additional
> > lock to qdisc to increase throughput")
> > 
> > Now kernel spinlocks are MCS, this busylock things is no longer
> > relevant. It is slowing down things a bit.
>  ...
> > That would be a 8 % increase.
> 
> Presumably only for x86-64 and other platforms that actually are using
> the ticket spinlocks.
> 
> For others it would be a regression.

Ticket spinlocks are actually gone, these are now MCS.

But yes, point taken ;)

      reply	other threads:[~2016-05-19 18:44 UTC|newest]

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-05-19 17:08 [RFC] net: remove busylock Eric Dumazet
2016-05-19 18:03 ` Alexander Duyck
2016-05-19 18:41   ` Rick Jones
2016-05-19 18:56   ` Eric Dumazet
2016-05-19 19:35     ` Eric Dumazet
2016-05-19 20:39       ` Alexander Duyck
2016-05-20  4:49         ` John Fastabend
2016-05-20  4:56           ` Eric Dumazet
2016-05-20  7:29   ` Jesper Dangaard Brouer
2016-05-20 13:11     ` Eric Dumazet
2016-05-20 13:47       ` Eric Dumazet
2016-05-20 14:16         ` Eric Dumazet
2016-05-20 17:49           ` Jesper Dangaard Brouer
2016-05-20 21:32             ` Eric Dumazet
2016-05-23  9:50               ` Jesper Dangaard Brouer
2016-05-23 21:24                 ` [PATCH net] net_sched: avoid too many hrtimer_start() calls Eric Dumazet
2016-05-24 21:49                   ` David Miller
2016-05-24 13:50             ` [RFC] net: remove busylock David Laight
2016-05-24 14:37               ` Eric Dumazet
2016-05-20 16:01       ` John Fastabend
2016-05-19 18:12 ` David Miller
2016-05-19 18:44   ` Eric Dumazet [this message]

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