use DISCARD for fill_policy since default RING_BUFFER fails when wrap around (most result table empty); add README.md and merge-trace.jl

scripts/merge-trace.jl

@@ -0,0 +1,37 @@
+using Base: String
+using JSON, DataFrames, Dates, CSV
+
+function check_input_args()
+    message = "Needs only one json file and at least one trace data file(s)."
+    @assert length(ARGS) >= 2 && occursin(".json", join(ARGS)) message
+    json_file, trace_files = nothing, String[]
+    for arg in ARGS
+        @assert Base.Filesystem.ispath(arg) "'$(arg)' not found!"
+        if endswith(arg, ".json")
+            json_file = arg
+        else
+            push!(trace_files, arg)
+        end
+    end
+    json_file, trace_files
+end
+
+json_file, trace_files = check_input_args()
+
+out = JSON.parsefile(json_file)
+for trace in trace_files
+    @info "processing $(trace) ..."
+    f = tempname() * ".json"
+    run(`trace_to_text json $trace $f`)
+    todo = JSON.parsefile(f)
+    out["traceEvents"] = vcat(
+        out["traceEvents"],
+        todo["traceEvents"])
+end
+
+output_file = replace("$(string(now())).json", ":" => "-")
+open(output_file, "w") do f
+    write(f, JSON.json(out))
+    @info "output file: $(output_file)"
+end
+