RE: [Xen-devel] Seeking performance numbers for flip vs. copy

["Santos, Jose Renato G" <joserenato.santos@xxxxxx>]

        From: xen-devel-bounces@xxxxxxxxxxxxxxxxxxx
[mailto:xen-devel-bounces@xxxxxxxxxxxxxxxxxxx] On Behalf Of Suzanne
McIntosh
        Sent: Monday, March 26, 2007 12:48 PM
        To: xen-devel@xxxxxxxxxxxxxxxxxxx
        Cc: Suzanne McIntosh
        Subject: [Xen-devel] Seeking performance numbers for flip vs.
copy
        
        

        Hi, 
        I am looking for performance numbers comparing the network
driver flip vs. copy feature 
        on a 32-bit machine. Could not locate this info in Xen archives.
Would appreciate any help. 
        
        Thanks, Sue 
        _______________________________________________________________
        Suzanne McIntosh 
        IBM T.J. Watson Research Center
        Secure Systems and Services 
        

Here is some old data that I have for comparing page flip with copy.
Note that this for Xen unstable  as of October 3, 2006.
I don't more recent data, but I believe the relative performance should
not have changed much, although the absolute numbers may be different
now.

I hope this helps

Renato

> Here are the results comparing copy and page flip.
> These results were using netperf TCP_STREAM test which use large size 
> packets.
> I run experiments for receiving and transmiting to from/to a external 
> client.
> The results show that copying use less cycles than page flip but dom0 
> has higher utilization (due to the copy).
> This caused dom0 cpu to saturate and reduced the throuhgput slightly
in
> my machine. I have a 4way Intel Xeon 2.8Ghz with 4GB of RAM (each
domain
> is using 512 MB of RAM).
> Copy is also better for the transmit experiment since the overhead for

> processing ACKs is reduced.
> 
> I will work on the transmit side optimizations starting tomorrow.
> 
> Regards
> 
> Renato
> 
> =======================================================
> receive:
> ------------------------------------------------------_
>      |        |                    | cycles/packet    |
>      |  Rate  |  CPU utilization   |  (thousands)     |
>      |  Mb/s  | dom0  dom1   tot   | dom0  dom1  tot  |
> -------------------------------------------------------
> flip | 941.34 | 84.2% 76.3% 160.4% | 30.1  27.2  57.3 |
> copy | 907.71 | 99.7% 45.2% 144.9% | 36.9  16.7  53.6 |
> -------------------------------------------------------
> 
> transmit:
> ------------------------------------
>      |        |                    |
>      |  Rate  |  CPU utilization   |
>      |  Mb/s  | dom0  dom1   tot   |
> ------------------------------------
> flip | 941.31 | 49.6% 43.9%  93.5% |
> copy | 941.30 | 45.2% 34.5%  79.7% |
> ------------------------------------

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