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From: Eric Dumazet <eric.dumazet@gmail.com>
To: David Ahern <dsahern@gmail.com>
Cc: David Miller <davem@davemloft.net>,
	netdev <netdev@vger.kernel.org>,
	Stephen Hemminger <stephen@networkplumber.org>
Subject: Re: [PATCH net-next] sch_netem: faster rb tree removal
Date: Mon, 25 Sep 2017 09:52:01 -0700	[thread overview]
Message-ID: <1506358321.6617.14.camel@edumazet-glaptop3.roam.corp.google.com> (raw)
In-Reply-To: <ce328dfd-0b54-883a-36a8-91ec344f86ad@gmail.com>

On Mon, 2017-09-25 at 10:14 -0600, David Ahern wrote:

> Thanks for the test.
> 
> I made a simple program this morning and ran it under perf. With the
> above suggestion the rb_erase has a high cost because it always deletes
> the root node. Your method 1 has a high cost on rb_first which is
> expected given its definition and it is run on each removal. Both
> options increase in time with the number of entries in the tree.
> 
> Your method 2 is fairly constant from 10,000 entries to 10M entries
> which makes sense: a one time cost at finding rb_first and then always
> removing a bottom node so rb_erase is light.
> 
> As for the change:
> 
> Acked-by: David Ahern <dsahern@gmail.com>

Thanks a lot for double checking !

  reply	other threads:[~2017-09-25 16:52 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-09-23 18:07 [PATCH net-next] sch_netem: faster rb tree removal Eric Dumazet
2017-09-25  1:57 ` David Ahern
2017-09-25  2:05   ` David Ahern
2017-09-25  5:27     ` Eric Dumazet
2017-09-25 16:14       ` David Ahern
2017-09-25 16:52         ` Eric Dumazet [this message]
2017-09-25 20:11         ` David Miller
2017-09-25 21:52           ` David Ahern
2017-09-26  3:33 ` David Miller

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