linux-kernel - Re: [PATCH V4 0/3] basic busy polling support for vhost

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Message-ID: <56E77D34.3050104@redhat.com>
Date:	Tue, 15 Mar 2016 11:10:44 +0800
From:	Jason Wang <jasowang@...hat.com>
To:	Michael Rapoport <RAPOPORT@...ibm.com>,
	Greg Kurz <gkurz@...ux.vnet.ibm.com>
Cc:	borntraeger@...ibm.com, kvm@...r.kernel.org,
	linux-kernel@...r.kernel.org, mst@...hat.com,
	netdev@...r.kernel.org, virtualization@...ts.linux-foundation.org,
	yang.zhang.wz@...il.com
Subject: Re: [PATCH V4 0/3] basic busy polling support for vhost_net



On 03/10/2016 02:48 PM, Michael Rapoport wrote:
> Hi Greg,
>
>> > Greg Kurz <gkurz@...ux.vnet.ibm.com> wrote on 03/09/2016 09:26:45 PM:
>>> > > On Fri,  4 Mar 2016 06:24:50 -0500
>>> > > Jason Wang <jasowang@...hat.com> wrote:
>> > 
>>> > > This series tries to add basic busy polling for vhost net. The idea is
>>> > > simple: at the end of tx/rx processing, busy polling for new tx added
>>> > > descriptor and rx receive socket for a while. The maximum number of
>>> > > time (in us) could be spent on busy polling was specified ioctl.
>>> > > 
>>> > > Test A were done through:
>>> > > 
>>> > > - 50 us as busy loop timeout
>>> > > - Netperf 2.6
>>> > > - Two machines with back to back connected mlx4
>> > 
>> > Hi Jason,
>> > 
>> > Could this also improve performance if both VMs are
>> > on the same host system ?
> I've experimented a little with Jason's patches and guest-to-guest netperf 
> when both guests were on the same host, and I saw improvements for that 
> case.
>  

Good to know this, I haven't tested this before but from the codes, it
should work for VM2VM case too.

Thanks a lot for the testing.