Linux Virtualization - Aug 2014 - [PATCH] vhost: Add polling mode

From: "Michael S. Tsirkin" <mst at redhat.com>
Date: Sun, 10 Aug 2014 21:45:59 +0200
> On Sun, Aug 10, 2014 at 11:30:35AM +0300, Razya Ladelsky wrote:
 ...
> And, did your tests actually produce 100% load on both host CPUs?
 ...

Michael, please do not quote an entire patch just to ask a one line
question.

I truly, truly, wish it was simpler in modern email clients to delete
the unrelated quoted material because I bet when people do this they
are simply being lazy.

Thank you.

On Mon, Aug 11, 2014 at 12:46:21PM -0700, David Miller
wrote:
> From: "Michael S. Tsirkin" <mst at redhat.com>
> Date: Sun, 10 Aug 2014 21:45:59 +0200
> 
> > On Sun, Aug 10, 2014 at 11:30:35AM +0300, Razya Ladelsky wrote:
>  ...
> > And, did your tests actually produce 100% load on both host CPUs?
>  ...
> 
> Michael, please do not quote an entire patch just to ask a one line
> question.
> 
> I truly, truly, wish it was simpler in modern email clients to delete
> the unrelated quoted material because I bet when people do this they
> are simply being lazy.
> 
> Thank you.
Lazy - mea culpa, though I'm using mutt so it isn't even hard.

The question still stands: the test results are only valid
if CPU was at 100% in all configurations.
This is the reason I generally prefer it when people report
throughput divided by CPU (power would be good too but it still
isn't easy for people to get that number).

-- 
MST

"Michael S. Tsirkin" <mst at redhat.com> wrote on 12/08/2014
12:18:50 PM:
> From: "Michael S. Tsirkin" <mst at redhat.com>
> To: David Miller <davem at davemloft.net>
> Cc: Razya Ladelsky/Haifa/IBM at IBMIL, kvm at vger.kernel.org, Alex 
> Glikson/Haifa/IBM at IBMIL, Eran Raichstein/Haifa/IBM at IBMIL, Yossi 
> Kuperman1/Haifa/IBM at IBMIL, Joel Nider/Haifa/IBM at IBMIL, 
> abel.gordon at gmail.com, linux-kernel at vger.kernel.org, 
> netdev at vger.kernel.org, virtualization at lists.linux-foundation.org
> Date: 12/08/2014 12:18 PM
> Subject: Re: [PATCH] vhost: Add polling mode
> 
> On Mon, Aug 11, 2014 at 12:46:21PM -0700, David Miller wrote:
> > From: "Michael S. Tsirkin" <mst at redhat.com>
> > Date: Sun, 10 Aug 2014 21:45:59 +0200
> > 
> > > On Sun, Aug 10, 2014 at 11:30:35AM +0300, Razya Ladelsky wrote:
> >  ...
> > > And, did your tests actually produce 100% load on both host CPUs?
> >  ...
> > 
> > Michael, please do not quote an entire patch just to ask a one line
> > question.
> > 
> > I truly, truly, wish it was simpler in modern email clients to delete
> > the unrelated quoted material because I bet when people do this they
> > are simply being lazy.
> > 
> > Thank you.
> 
> Lazy - mea culpa, though I'm using mutt so it isn't even hard.
> 
> The question still stands: the test results are only valid
> if CPU was at 100% in all configurations.
> This is the reason I generally prefer it when people report
> throughput divided by CPU (power would be good too but it still
> isn't easy for people to get that number).
> 
Hi Michael,

Sorry for the delay, had some problems with my mailbox, and I realized 
just now that 
my reply wasn't sent.
The vm indeed ALWAYS utilized 100% cpu, whether polling was enabled or 
not.
The vhost thread utilized less than 100% (of the other cpu) when polling 
was disabled.
Enabling polling increased its utilization to 100% (in which case both 
cpus were 100% utilized). 

> -- 
> MST
>