0 latency issue with pipeline mode

[NaerChang]

First of all I am using dockerized version of wrk (https://github.com/William-Yeh/docker-wrk). I use the pipeline method via lua script to run the perf test but latency data is all 0 and stdev becomes -nan%.

I am trying to understand in what case this would happen. I know it's can't be exactly 0 (rounding issue?). All REST API calls are between docker containers on the coreos host which is similar to just doing inter process communication. When I use curl I get latency data that is 1-3ms.

[binakot]

Same issue here. Using smth like that:

init = function(args)
   local r = {}
   r[1] = wrk.format(nil, "/?foo")
   r[2] = wrk.format(nil, "/?bar")
   r[3] = wrk.format(nil, "/?baz")

   req = table.concat(r)
end

request = function()
   return req
end

And the result:

  Thread Stats   Avg      Stdev     Max   +/- Stdev
    Latency   366.38ms  373.46ms   1.04s     0.00%
    Req/Sec     3.00      1.44    10.00     93.55%
  Latency Distribution
     50%    0.00us
     75%    0.00us
     90%    0.00us
     99%    0.00us
  31 requests in 10.06s, 19.03KB read
Requests/sec:      3.08
Transfer/sec:      1.89KB

All data is correct except latency. Seems like it's broken when pipelines are using...