Re: [rcu] c0f489d2c6f: -1.5% netperf.Throughput_tps

[Aaron Lu <aaron.lu@intel.com>]

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On 07/25/2014 03:35 PM, Mike Galbraith wrote:
> On Fri, 2014-07-25 at 14:45 +0800, Aaron Lu wrote: 
>> FYI, we noticed the below changes on
>>
>> git://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git master
>> commit c0f489d2c6fec8994c642c2ec925eb858727dc7b ("rcu: Bind grace-period kthreads to non-NO_HZ_FULL CPUs")
>>
>> abaa93d9e1de2c2  c0f489d2c6fec8994c642c2ec  
>> ---------------  -------------------------  
>>      12654 ~ 0%      -1.5%      12470 ~ 0%  ivb43/netperf/300s-25%-TCP_CRR
>>      12654 ~ 0%      -1.5%      12470 ~ 0%  TOTAL netperf.Throughput_tps
> 
> Out of curiosity, what parameters do you use for this test?  In my

The cmdline for this test is:
netperf -t TCP_CRR -c -C -l 300

> piddling around with high frequency switching loads, they tend to have
> too much build to build and boot to boot variance to track 1.5%.

The actual results are not 100% stable, here is the values of the 5
runs:

$ cat [0-4]/netperf.json 
{
  "netperf.Throughput_tps": [
    12674.061666666668
  ]
}{
  "netperf.Throughput_tps": [
    12705.6325
  ]
}{
  "netperf.Throughput_tps": [
    12621.97333333333
  ]
}{
  "netperf.Throughput_tps": [
    12604.785000000002
  ]
}{
  "netperf.Throughput_tps": [
    12664.158333333333
  ]

I suppose the way the stddev% is calculated by first calculating the
average and then compare the individual value with the average.
Fengguang, is this correct?

Thanks,
Aaron