如何配置我的 elixir phoenix 服务器？

Question

I have a Phoenix server which basically proxies GraphQL into a lot of REST API backends. It finds the username from a provided JWT, and chooses the appropriate backend.

Now, I benchmarked the backends to be able to handle 13K req/sec. But my GraphQL frontend can only do 400 req/sec, and in dev mode only 15 req/sec..

I am suspecting the JWT processing is the problem here, but how do I confirm that?

I tried :observer, but this output confuses me (what are 'Reductions'?)

EDIT: I was pointed to erlang tracer and fprof. So I decided to try fprof. Found this blog post . This is my console output, and now I'm stuck again:

iex(wobble@localhost)1> :fprof.trace([start, {procs, [whereis(my_web) ]}])
** (CompileError) iex:1: undefined function start/0

iex(wobble@localhost)1> :fprof.trace([:start, {procs, [whereis(my_web) ]}])
** (CompileError) iex:1: undefined function procs/0
    (stdlib) lists.erl:1354: :lists.mapfoldl/3

iex(wobble@localhost)1> :fprof.trace([:start, {:procs, [whereis(my_web) ]}])
** (CompileError) iex:1: undefined function whereis/1
    (stdlib) lists.erl:1354: :lists.mapfoldl/3
    (stdlib) lists.erl:1355: :lists.mapfoldl/3

iex(wobble@localhost)1> :fprof.trace([:start, {:procs, [:whereis(my_web) ]}])
** (SyntaxError) iex:1: syntax error before: '('

Answer 1

Reductions are unit of the execution in Erlang. You can think about it as an instruction in machine code.

What you want to do is to run tracer . It will tell you how often are your functions called.