From 0e95886a2e2b41c210b1bddea17fd052679804d0 Mon Sep 17 00:00:00 2001
From: Petrik <petrik@deheus.net>
Date: Sun, 5 Nov 2023 13:13:01 +0100
Subject: [PATCH] [ruby/padrino] Use auto_tune.rb for Puma and Unicorn config

Use the same script that is used by other Ruby frameworks.
Datamapper has a connection pool of 8, so that should be the max
concurrency.
---
 frameworks/Ruby/padrino/config/auto_tune.rb | 41 +++++++++++++++++++++
 frameworks/Ruby/padrino/config/puma.rb      | 10 ++++-
 frameworks/Ruby/padrino/config/unicorn.rb   |  6 ++-
 3 files changed, 54 insertions(+), 3 deletions(-)
 create mode 100644 frameworks/Ruby/padrino/config/auto_tune.rb

diff --git a/frameworks/Ruby/padrino/config/auto_tune.rb b/frameworks/Ruby/padrino/config/auto_tune.rb
new file mode 100644
index 00000000000..4544231b9d2
--- /dev/null
+++ b/frameworks/Ruby/padrino/config/auto_tune.rb
@@ -0,0 +1,41 @@
+#!/usr/bin/env ruby
+# Instantiate about one process per X MiB of available memory, scaling up to as
+# close to MAX_THREADS as possible while observing an upper bound based on the
+# number of virtual/logical CPUs. If there are fewer processes than
+# MAX_THREADS, add threads per process to reach MAX_THREADS.
+require 'etc'
+
+KB_PER_WORKER = 128 * 1_024 # average of peak PSS of single-threaded processes (watch smem -k)
+MIN_WORKERS = 2
+MAX_WORKERS_PER_VCPU = 1.25 # virtual/logical
+MIN_THREADS_PER_WORKER = 1
+MAX_THREADS = Integer(ENV['MAX_CONCURRENCY'] || 8)
+
+def meminfo(arg)
+  File.open('/proc/meminfo') do |f|
+    f.each_line do |line|
+      key, value = line.split(/:\s+/)
+      return value.split(/\s+/).first.to_i if key == arg
+    end
+  end
+
+  fail "Unable to find `#{arg}' in /proc/meminfo!"
+end
+
+def auto_tune
+  avail_mem = meminfo('MemAvailable') * 0.8 - MAX_THREADS * 1_024
+
+  workers = [
+    [(1.0 * avail_mem / KB_PER_WORKER).floor, MIN_WORKERS].max,
+    (Etc.nprocessors * MAX_WORKERS_PER_VCPU).ceil
+  ].min
+
+  threads_per_worker = [
+    workers < MAX_THREADS ? (1.0 * MAX_THREADS / workers).ceil : -Float::INFINITY,
+    MIN_THREADS_PER_WORKER
+  ].max
+
+  [workers, threads_per_worker]
+end
+
+p auto_tune if $0 == __FILE__
diff --git a/frameworks/Ruby/padrino/config/puma.rb b/frameworks/Ruby/padrino/config/puma.rb
index a4adcc8ded8..8a42642fd61 100644
--- a/frameworks/Ruby/padrino/config/puma.rb
+++ b/frameworks/Ruby/padrino/config/puma.rb
@@ -1,3 +1,9 @@
+require_relative 'auto_tune'
+
+num_workers, num_threads = auto_tune
+
+workers num_workers
+threads num_threads, num_threads
+
 environment 'production'
-threads 8, 32
-bind 'tcp://0.0.0.0:8080'
\ No newline at end of file
+bind 'tcp://0.0.0.0:8080'
diff --git a/frameworks/Ruby/padrino/config/unicorn.rb b/frameworks/Ruby/padrino/config/unicorn.rb
index fa84460c73d..9ca3171328b 100644
--- a/frameworks/Ruby/padrino/config/unicorn.rb
+++ b/frameworks/Ruby/padrino/config/unicorn.rb
@@ -1,4 +1,8 @@
-worker_processes 8
+require_relative 'auto_tune'
+
+num_workers, = auto_tune
+
+worker_processes num_workers
 listen "/tmp/.sock", :backlog => 4096
 
 preload_app true