96 lines
2.4 KiB
Ruby
96 lines
2.4 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 = 3
|
|
|
|
# TUNE ME, for Discourse this number is good
|
|
MIN_FREE_SLOTS = 50_000
|
|
|
|
def verbose(msg=nil)
|
|
@verbose ||= ENV["OOBGC_VERBOSE"] == "1" ? :true : :false
|
|
if @verbose == :true
|
|
if(msg)
|
|
puts msg
|
|
end
|
|
|
|
true
|
|
end
|
|
end
|
|
|
|
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
|
|
|
|
# the closer this is to the GC run the more accurate it is
|
|
def estimate_live_num_at_gc(stat)
|
|
stat[:heap_live_num] + stat[:heap_free_num]
|
|
end
|
|
|
|
def process_client(client)
|
|
stat = GC.stat
|
|
|
|
@num_requests ||= 0
|
|
@num_requests += 1
|
|
|
|
gc_count = stat[:count]
|
|
live_num = stat[:heap_live_num]
|
|
|
|
@expect_gc_at ||= estimate_live_num_at_gc(stat)
|
|
|
|
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
|
|
delta = new_live_num - live_num
|
|
|
|
@max_delta ||= delta
|
|
|
|
if delta > @max_delta
|
|
new_delta = (delta * 1.5).to_i
|
|
@max_delta = [new_delta, delta].min
|
|
else
|
|
# this may seem like a very tiny decay rate, but some apps using caching
|
|
# can really mess stuff up, if our delta is too low the algorithm fails
|
|
new_delta = (delta * 0.995).to_i
|
|
@max_delta = [new_delta, delta].max
|
|
end
|
|
|
|
if @max_delta < MIN_FREE_SLOTS
|
|
@max_delta = MIN_FREE_SLOTS
|
|
end
|
|
|
|
if @num_requests > MIN_REQUESTS_PER_OOBGC && @max_delta * 2 + new_live_num > @expect_gc_at
|
|
t = Time.now
|
|
GC.start
|
|
stat = GC.stat
|
|
@expect_gc_at = estimate_live_num_at_gc(stat)
|
|
verbose "OobGC hit pid: #{Process.pid} req: #{@num_requests} max delta: #{@max_delta} expect at: #{@expect_gc_at} #{((Time.now - t) * 1000).to_i}ms saved"
|
|
@num_requests = 0
|
|
end
|
|
else
|
|
|
|
verbose "OobGC miss pid: #{Process.pid} reqs: #{@num_requests} max delta: #{@max_delta}"
|
|
|
|
@num_requests = 0
|
|
@expect_gc_at = estimate_live_num_at_gc(stat)
|
|
|
|
end
|
|
|
|
end
|
|
|
|
end
|