Subject: L2 network namespaces + macvlan performances

From: Benjamin Thery <[email-masked]>
Date: Fri, 06 Jul 2007 18:48:15 +0200

Following a discussion we had at OLS concerning L2 network namespace
performances and how the new macvlan driver could potentially improve
them, I've ported the macvlan patchset on top of Eric's net namespace
patchset on 2.6.22-rc4-mm2.

A little bit of history:

Some months ago, when we ran some performance tests (using netperf)
on net namespace, we observed the following things:

Using 'etun', the virtual ethernet tunnel driver, and IP routes
from inside a network namespace,

- The throughput is the same as the "normal" case(*)
   (* normal case: no namespace, using physical adapters).
   No regression. Good.

- But the CPU load increases a lot. Bad.
   The reasons are:
	- All checksums are done in software. No hardware offloading.
	- Every TCP packets going through the etun devices are
	  duplicated in ip_forward() before we decrease the ttl.
           (packets are routed between both ends of etun)

We also made some testing with bridges, and obtained the same results:
	CPU load increase:
	- No hardware offloading
	- Packets are duplicated somewhere in the bridge+netfilter
           code (can't remember where right now)

This time, I've replaced the etun interface by the new macvlan,
which should benefits from the hardware offloading capabilities of the
physical adapter and suppress the forwarding stuff.

My test setup is:

   Host A                    Host B
  ______________            ___________
|  _________   |          |           |
| | Netns 1 |  |          |           |
| |         |  |          |           |
| | macvlan0|  |          |           |
| |___|_____|  |          |           |
|     |        |          |           |
|_____|________|          |___________|
       | eth0 (192.168.0.2)     | eth0 (192.168.0.1)
       |                        |
-----------------------------------------
macvlan0 (192.168.0.3)

- netperf runs on host A
- netserver runs on host B
- Adapters speed is 1GB/s

On this setup I ran the following netperf tests: TCP_STREAM, 
TCP_MAERTS, TCP_RR, UDP_STREAM, UDP_RR.

Between the "normal" case and the "net namespace + macvlan" case, 
results are  about the same for both the throughput and the local CPU 
load for the following test types: TCP_MAERTS, TCP_RR, UDP_STREAM, UDP_RR.

macvlan looks like a very good candidate for network namespace in 
these cases.

But, with the TCP_STREAM test, I observed the CPU load is about the
same (that's what we wanted) but the throughput decreases by about 5%:
from 850MB/s down to 810MB/s.
I haven't investigated yet why the throughput decrease in the case.
Does it come from my setup, from macvlan additional treatments, other? 
I don't know yet

Attached to this email you'll find the raw netperf outputs for the 
three cases:

- netperf through a physical adapter, no namespace:
	netperf-results-2.6.22-rc4-mm2-netns1-vanilla.txt	
- netperf through etun, inside a namespace:
	netperf-results-2.6.22-rc4-mm2-netns1-using-etun.txt	
- netperf through macvlan, inside a namespace:
	netperf-results-2.6.22-rc4-mm2-netns1-using-macvlan.txt

macvlan looks promising.

Regards,
Benjamin

-- 
B e n j a m i n   T h e r y  - BULL/DT/Open Software R&D

    http://www.bull.com
NETPERF RESULTS: the "normal" case : 
====================================
No network namespace, traffic goes through real 1GB/s physical adapters.

------------------------------------------------
TCP STREAM TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to 192.168.76.1 (192.168.76.1) port 0 AF_INET : +/-2.5% @ 95% conf.
Recv   Send    Send                          Utilization       Service Demand
Socket Socket  Message  Elapsed              Send     Recv     Send    Recv
Size   Size    Size     Time     Throughput  local    remote   local   remote
bytes  bytes   bytes    secs.    10^6bits/s  % S      % S      us/KB   us/KB

 87380  16384   1400    20.03       857.39   6.39     9.75     2.444   3.727  
------------------------------------------------
 
------------------------------------------------
TCP MAERTS TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to 192.168.76.1 (192.168.76.1) port 0 AF_INET : +/-2.5% @ 95% conf.
Recv   Send    Send                          Utilization       Service Demand
Socket Socket  Message  Elapsed              Send     Recv     Send    Recv
Size   Size    Size     Time     Throughput  local    remote   local   remote
bytes  bytes   bytes    secs.    10^6bits/s  % S      % S      us/KB   us/KB

 87380  16384  87380    20.03       763.15   4.75     10.33    2.038   4.434  
------------------------------------------------
 
------------------------------------------------
TCP REQUEST/RESPONSE TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to 192.168.76.1 (192.168.76.1) port 0 AF_INET : +/-2.5% @ 95% conf.
Local /Remote
Socket Size   Request Resp.  Elapsed Trans.   CPU    CPU    S.dem   S.dem
Send   Recv   Size    Size   Time    Rate     local  remote local   remote
bytes  bytes  bytes   bytes  secs.   per sec  % S    % S    us/Tr   us/Tr

16384  87380  1       1      20.00   12594.24  4.16   6.06   13.212  19.231 
16384  87380 
------------------------------------------------
 
------------------------------------------------
UDP UNIDIRECTIONAL SEND TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to 192.168.76.1 (192.168.76.1) port 0 AF_INET : +/-2.5% @ 95% conf.
Socket  Message  Elapsed      Messages                   CPU      Service
Size    Size     Time         Okay Errors   Throughput   Util     Demand
bytes   bytes    secs            #      #   10^6bits/sec % SS     us/KB

110592    1400   20.00     1701653      0      952.9     6.84     2.354 
107520           20.00     1701647             952.9     9.66     3.321 

------------------------------------------------
 
------------------------------------------------
UDP REQUEST/RESPONSE TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to 192.168.76.1 (192.168.76.1) port 0 AF_INET : +/-2.5% @ 95% conf.
Local /Remote
Socket Size   Request Resp.  Elapsed Trans.   CPU    CPU    S.dem   S.dem
Send   Recv   Size    Size   Time    Rate     local  remote local   remote
bytes  bytes  bytes   bytes  secs.   per sec  % S    % S    us/Tr   us/Tr

110592 110592 1       1      20.00   13789.92   3.82   6.16   11.087  17.855
107520 107520
------------------------------------------------

NETPERF RESULTS: the etun case :
====================================
netperf is ran from a network namespace, 
traffic goes through etun adapters.

------------------------------------------------
TCP STREAM TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to 192.168.76.1 (192.168.76.1) port 0 AF_INET : +/-2.5% @ 95% conf.
Recv   Send    Send                          Utilization       Service Demand
Socket Socket  Message  Elapsed              Send     Recv     Send    Recv
Size   Size    Size     Time     Throughput  local    remote   local   remote
bytes  bytes   bytes    secs.    10^6bits/s  % S      % U      us/KB   us/KB

 87380  16384   1400    40.02       840.64   12.89    -1.00    5.025   -1.000 
------------------------------------------------
 
------------------------------------------------
TCP MAERTS TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to 192.168.76.1 (192.168.76.1) port 0 AF_INET : +/-2.5% @ 95% conf.
Recv   Send    Send                          Utilization       Service Demand
Socket Socket  Message  Elapsed              Send     Recv     Send    Recv
Size   Size    Size     Time     Throughput  local    remote   local   remote
bytes  bytes   bytes    secs.    10^6bits/s  % S      % U      us/KB   us/KB

 87380  16384  87380    40.03       763.30   6.29     -1.00    2.701   -1.000 
------------------------------------------------
 
------------------------------------------------
TCP REQUEST/RESPONSE TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to 192.168.76.1 (192.168.76.1) port 0 AF_INET : +/-2.5% @ 95% conf.
Local /Remote
Socket Size   Request Resp.  Elapsed Trans.   CPU    CPU    S.dem   S.dem
Send   Recv   Size    Size   Time    Rate     local  remote local   remote
bytes  bytes  bytes   bytes  secs.   per sec  % S    % U    us/Tr   us/Tr

16384  87380  1       1      40.00   12230.34  4.64   -1.00  15.167  -1.000 
16384  87380 
------------------------------------------------
 
------------------------------------------------
UDP UNIDIRECTIONAL SEND TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to 192.168.76.1 (192.168.76.1) port 0 AF_INET : +/-2.5% @ 95% conf.
Socket  Message  Elapsed      Messages                   CPU      Service
Size    Size     Time         Okay Errors   Throughput   Util     Demand
bytes   bytes    secs            #      #   10^6bits/sec % SU     us/KB

110592    1400   40.00     12981742      0     3634.7     25.64    8.801 
107520           40.00     3409123             954.5     -1.00    -1.000

------------------------------------------------
 
------------------------------------------------
UDP REQUEST/RESPONSE TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to 192.168.76.1 (192.168.76.1) port 0 AF_INET : +/-2.5% @ 95% conf.
Local /Remote
Socket Size   Request Resp.  Elapsed Trans.   CPU    CPU    S.dem   S.dem
Send   Recv   Size    Size   Time    Rate     local  remote local   remote
bytes  bytes  bytes   bytes  secs.   per sec  % S    % U    us/Tr   us/Tr

110592 110592 1       1      40.00   13385.96   4.22   -1.00  12.658  -1.000
107520 107520
------------------------------------------------

NETPERF RESULTS: the "normal" case :
====================================
netperf is ran from a network namespace,
traffic goes through a macvlan adapter.

------------------------------------------------
TCP STREAM TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to 192.168.76.1 (192.168.76.1) port 0 AF_INET : +/-2.5% @ 95% conf.
Recv   Send    Send                          Utilization       Service Demand
Socket Socket  Message  Elapsed              Send     Recv     Send    Recv
Size   Size    Size     Time     Throughput  local    remote   local   remote
bytes  bytes   bytes    secs.    10^6bits/s  % S      % S      us/KB   us/KB

 87380  16384   1400    20.03       817.40   7.26     12.96    2.912   5.200  
------------------------------------------------
 
------------------------------------------------
TCP MAERTS TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to 192.168.76.1 (192.168.76.1) port 0 AF_INET : +/-2.5% @ 95% conf.
Recv   Send    Send                          Utilization       Service Demand
Socket Socket  Message  Elapsed              Send     Recv     Send    Recv
Size   Size    Size     Time     Throughput  local    remote   local   remote
bytes  bytes   bytes    secs.    10^6bits/s  % S      % S      us/KB   us/KB

 87380  16384  87380    20.03       763.33   4.95     10.32    2.127   4.429  
------------------------------------------------
 
------------------------------------------------
TCP REQUEST/RESPONSE TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to 192.168.76.1 (192.168.76.1) port 0 AF_INET : +/-2.5% @ 95% conf.
Local /Remote
Socket Size   Request Resp.  Elapsed Trans.   CPU    CPU    S.dem   S.dem
Send   Recv   Size    Size   Time    Rate     local  remote local   remote
bytes  bytes  bytes   bytes  secs.   per sec  % S    % S    us/Tr   us/Tr

16384  87380  1       1      20.00   12448.36  4.34   6.21   13.950  19.939 
16384  87380 
------------------------------------------------
 
------------------------------------------------
UDP UNIDIRECTIONAL SEND TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to 192.168.76.1 (192.168.76.1) port 0 AF_INET : +/-2.5% @ 95% conf.
Socket  Message  Elapsed      Messages                   CPU      Service
Size    Size     Time         Okay Errors   Throughput   Util     Demand
bytes   bytes    secs            #      #   10^6bits/sec % SS     us/KB

110592    1400   20.00     1704200      0      954.3     7.11     2.440 
107520           20.00     1704194             954.3     9.66     3.318 

------------------------------------------------
 
------------------------------------------------
UDP REQUEST/RESPONSE TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to 192.168.76.1 (192.168.76.1) port 0 AF_INET : +/-2.5% @ 95% conf.
Local /Remote
Socket Size   Request Resp.  Elapsed Trans.   CPU    CPU    S.dem   S.dem
Send   Recv   Size    Size   Time    Rate     local  remote local   remote
bytes  bytes  bytes   bytes  secs.   per sec  % S    % S    us/Tr   us/Tr

110592 110592 1       1      20.00   13751.49   3.98   6.09   11.625  17.788
107520 107520
------------------------------------------------