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

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

This data was for transferring 1500 byte data packets with TCP. Note that the difference of performance on transmit is due to the receive of ACK packets (small size).

The domains were not explicitly pinned, but since there were only two domains (dom0 and domU) in a 4-cpu machine they were running on different CPUs.

 

Renato

---

From: xen-devel-bounces@xxxxxxxxxxxxxxxxxxx [mailto:xen-devel-bounces@xxxxxxxxxxxxxxxxxxx] On Behalf Of Suzanne McIntosh
Sent: Tuesday, March 27, 2007 11:15 AM
To: Santos, Jose Renato G
Cc: xen-devel@xxxxxxxxxxxxxxxxxxx; Suzanne McIntosh
Subject: RE: [Xen-devel] Seeking performance numbers for flip vs. copy

Thanks so much - this is very helpful.
For comparison purposes, it would be great to know the message size. Also wondering if doms were pinned?

Regards, Sue

_______________________________________________________________
Suzanne McIntosh
IBM T.J. Watson Research Center
Secure Systems and Services

"Santos, Jose Renato G" <joserenato.santos@xxxxxx>
Sent by: xen-devel-bounces@xxxxxxxxxxxxxxxxxxx

03/26/2007 06:25 PM

To	Suzanne McIntosh/Watson/IBM@IBMUS
cc	Xen Development Mailing List <xen-devel@xxxxxxxxxxxxxxxxxxx>
Subject	RE: [Xen-devel] Seeking performance numbers for flip vs. copy

 

                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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