discourse/lib/middleware/unicorn_oobgc.rb

69 lines
1.8 KiB
Ruby

# Hook into unicorn, unicorn middleware, not rack middleware
#
# Since we need no knowledge about the request we can simply
# hook unicorn
module Middleware::UnicornOobgc
MIN_REQUESTS_PER_OOBGC = 5
MAX_DELTAS = 25
def self.init
# hook up HttpServer intercept
ObjectSpace.each_object(Unicorn::HttpServer) do |s|
s.extend(self)
end
rescue
puts "Attempted to patch Unicorn but it is not loaded"
end
def process_client(client)
stat = GC.stat
@previous_deltas ||= []
@num_requests ||= 0
@num_requests += 1
# only track N deltas
if @previous_deltas.length > MAX_DELTAS
@previous_deltas.delete_at(0)
end
gc_count = stat[:count]
live_num = stat[:heap_live_num]
super(client) # Unicorn::HttpServer#process_client
# at this point client is serviced
stat = GC.stat
new_gc_count = stat[:count]
new_live_num = stat[:heap_live_num]
# no GC happened during the request
if new_gc_count == gc_count
@previous_deltas << (new_live_num - live_num)
if @gc_live_num && @num_requests > MIN_REQUESTS_PER_OOBGC
largest = @previous_deltas.max
if (largest * 3) + new_live_num > @gc_live_num
# While tuning consider printing this out, each time this happens you saved
# a user from running a GC inline
# t = Time.now
GC.start
# puts "OobGC invoked req count: #{@num_requests} largest delta: #{largest} #{((Time.now - t) * 1000).to_i}ms saved"
@num_requests = 0
end
end
else
puts "OobGC: GC live num adjusted: old live_num #{@gc_live_num} new: #{live_num} - reqs since GC: #{@num_requests} largest delta: #{@previous_deltas.max}"
@num_requests = 0
@gc_live_num = live_num
end
end
end