linux-kernel - Re: epoll_wait() performance

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Message-ID: <20191219085722.23e39028@carbon>
Date:   Thu, 19 Dec 2019 08:57:22 +0100
From:   Jesper Dangaard Brouer <brouer@...hat.com>
To:     David Laight <David.Laight@...LAB.COM>
Cc:     'Marek Majkowski' <marek@...udflare.com>,
        linux-kernel <linux-kernel@...r.kernel.org>,
        network dev <netdev@...r.kernel.org>,
        kernel-team <kernel-team@...udflare.com>,
        Paolo Abeni <pabeni@...hat.com>, brouer@...hat.com
Subject: Re: epoll_wait() performance

On Thu, 28 Nov 2019 16:37:01 +0000
David Laight <David.Laight@...LAB.COM> wrote:

> From: Jesper Dangaard Brouer
> > Sent: 28 November 2019 11:12  
> ...
> > > Can you test recv() as well?  
> > 
> > Sure: https://github.com/netoptimizer/network-testing/commit/9e3c8b86a2d662
> > 
> > $ sudo taskset -c 1 ./udp_sink --port 9  --count $((10**6*2))
> >           	run      count   	ns/pkt	pps		cycles	payload
> > recvMmsg/32  	run:  0	 2000000	653.29	1530704.29	2351	18	 demux:1
> > recvmsg   	run:  0	 2000000	631.01	1584760.06	2271	18	 demux:1
> > read      	run:  0	 2000000	582.24	1717518.16	2096	18	 demux:1
> > recvfrom  	run:  0	 2000000	547.26	1827269.12	1970	18	 demux:1
> > recv      	run:  0	 2000000	547.37	1826930.39	1970	18	 demux:1
> >   
> > > I think it might be faster than read().  
> > 
> > Slightly, but same speed as recvfrom.  
> 
> I notice that you recvfrom() code doesn't request the source address.
> So is probably identical to recv().

Created a GitHub issue/bug on this:
 https://github.com/netoptimizer/network-testing/issues/5

Feel free to fix this and send a patch/PR.

-- 
Best regards,
  Jesper Dangaard Brouer
  MSc.CS, Principal Kernel Engineer at Red Hat
  LinkedIn: http://www.linkedin.com/in/brouer