Re: [Xen-devel] [PATCH] Network Checksum Removal

[Andrew Theurer <habanero@xxxxxxxxxx>]

First round of test results for netperf2:  I will also run domU->domU, 
and all of these tests again with domians on different cpus (these are 
all on the same HW thread).

The cpu util is from xc_domain_get_cpu_usage(), not sar, vmstat, etc (I 
am not confident those are accurate for Xen right now).

DomU cpu util is about 2% lower on domU->host, which is about the % time 
spent in csum_partial_copy based on a timer int based oprofile.  Not 
sure why dom0 uses that extra 2% cpu, and we see maybe 1% throughput 
increase in our best cases.  I do think cpu util in dom0 is the biggest 
problem right now.  On this same box, we might use 30% of one cpu total 
to max out this Gbps adapter (tg3).  Adding ~60% cpu to just "proxy" 
this network seems like a lot.

Dom0 to domU is quite good, 13% better in the best case.

Also note the horrible throughput rates for 64 byte messages, most 
likely due to excessive context switching.

Also, BTW, this is the "old" bridge networking, no veth0 used yet.

-Andrew

3.2 GHz Xeon with Hyperhtreading, 1GB memory
                                                                                
                                                    
Benchmark: netperf2 -T TCP_STREAM
                                                                                
                                                    
dom0 and dom1 on cpu0 (first SMT thread on first core)
 domU to host
  "hw" tx csum
   msg-size: 00064  Mbps: 0186  d0-cpu: 49.38  d1-cpu: 44.35
   msg-size: 01500  Mbps: 0917  d0-cpu: 62.13  d1-cpu: 37.87
   msg-size: 16384  Mbps: 0933  d0-cpu: 66.63  d1-cpu: 33.37
   msg-size: 32768  Mbps: 0928  d0-cpu: 66.96  d1-cpu: 32.66
  sw tx csum
   msg-size: 00064  Mbps: 0187  d0-cpu: 49.50  d1-cpu: 44.52
   msg-size: 01500  Mbps: 0904  d0-cpu: 60.63  d1-cpu: 39.36
   msg-size: 16384  Mbps: 0924  d0-cpu: 63.98  d1-cpu: 35.98
   msg-size: 32768  Mbps: 0926  d0-cpu: 64.18  d1-cpu: 35.68
 domU to dom0
  "hw" csum
   msg-size: 00064  Mbps: 0014  d0-cpu: 64.02  d1-cpu: 31.71
   msg-size: 01500  Mbps: 1087  d0-cpu: 63.34  d1-cpu: 36.67
   msg-size: 16384  Mbps: 1204  d0-cpu: 67.30  d1-cpu: 32.71
   msg-size: 32768  Mbps: 1148  d0-cpu: 68.08  d1-cpu: 31.93
  sw tx csum
   msg-size: 00064  Mbps: 0014  d0-cpu: 64.88  d1-cpu: 32.39
   msg-size: 01500  Mbps: 0948  d0-cpu: 62.20  d1-cpu: 37.80
   msg-size: 16384  Mbps: 1063  d0-cpu: 64.73  d1-cpu: 35.27
   msg-size: 32768  Mbps: 1012  d0-cpu: 65.71  d1-cpu: 34.30


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