html_url,issue_url,id,node_id,user,created_at,updated_at,author_association,body,reactions,performed_via_github_app,issue https://github.com/pydata/xarray/pull/1983#issuecomment-382071801,https://api.github.com/repos/pydata/xarray/issues/1983,382071801,MDEyOklzc3VlQ29tbWVudDM4MjA3MTgwMQ==,1117224,2018-04-17T17:14:33Z,2018-04-17T17:38:42Z,NONE,"Thanks @jhamman for working on this! I did a test on my real world data (1202 ~3mb files) on my local computer and am not getting results I expected: 1) No speed up with parallel=True 2) _Slow down_ when using distributed (processes=16 cores=16). Am I missing something? ```python nc_files = glob.glob(E.obs['NSIDC_0081']['sipn_nc']+'/*.nc') print(len(nc_files)) 1202 # Parallel False %time ds = xr.open_mfdataset(nc_files, concat_dim='time', parallel=False, autoclose=True) CPU times: user 57.8 s, sys: 3.2 s, total: 1min 1s Wall time: 1min # Parallel True with default scheduler %time ds = xr.open_mfdataset(nc_files, concat_dim='time', parallel=True, autoclose=True) CPU times: user 1min 16s, sys: 9.82 s, total: 1min 26s Wall time: 1min 16s # Parallel True with distributed from dask.distributed import Client client = Client() print(client) %time ds = xr.open_mfdataset(nc_files, concat_dim='time', parallel=True, autoclose=True) CPU times: user 2min 17s, sys: 12.3 s, total: 2min 29s Wall time: 3min 48s ``` On feature/parallel_open_netcdf commit 280a46f13426a462fb3e983cfd5ac7a0565d1826","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,304589831