Chromium trace output does not work

[bwesen]

When parsing something into the chromium trace format, the JSON that is output is broken, it has a missing field and each element in the array starts with a , which is illegal json format (and the chrome tracing load complains):

[,{"name": "0x0000000000431FD7 [main]","ph": "B","ts": 3627138130963.042,"pid": 10357,"tid": 10357}

This after: # ./nperf trace-events -o main_prof.trace --granularity line main_prof