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Diffstat (limited to 'config/initializers/stackprof.rb')
| -rw-r--r-- | config/initializers/stackprof.rb | 135 |
1 files changed, 0 insertions, 135 deletions
diff --git a/config/initializers/stackprof.rb b/config/initializers/stackprof.rb index 4c4d241f065..4ff219cfda1 100644 --- a/config/initializers/stackprof.rb +++ b/config/initializers/stackprof.rb @@ -1,140 +1,5 @@ # frozen_string_literal: true -# trigger stackprof by sending a SIGUSR2 signal -# -# Docs: https://docs.gitlab.com/ee/development/performance.html#production - -module Gitlab - class StackProf - DEFAULT_FILE_PREFIX = Dir.tmpdir - DEFAULT_TIMEOUT_SEC = 30 - DEFAULT_MODE = :cpu - # Sample interval as a frequency in microseconds (~100hz); appropriate for CPU profiles - DEFAULT_INTERVAL_US = 10_000 - # Sample interval in event occurrences (n = every nth event); appropriate for allocation profiles - DEFAULT_INTERVAL_EVENTS = 1_000 - - # this is a workaround for sidekiq, which defines its own SIGUSR2 handler. - # by defering to the sidekiq startup event, we get to set up our own - # handler late enough. - # see also: https://github.com/mperham/sidekiq/pull/4653 - def self.install - require 'stackprof' - require 'tmpdir' - - if Gitlab::Runtime.sidekiq? - Sidekiq.configure_server do |config| - config.on :startup do - on_worker_start - end - end - else - Gitlab::Cluster::LifecycleEvents.on_worker_start do - on_worker_start - end - end - end - - def self.on_worker_start - log_event('listening for SIGUSR2 signal') - - # create a pipe in order to propagate signal out of the signal handler - # see also: https://cr.yp.to/docs/selfpipe.html - read, write = IO.pipe - - # create a separate thread that polls for signals on the pipe. - # - # this way we do not execute in signal handler context, which - # lifts restrictions and also serializes the calls in a thread-safe - # manner. - # - # it's very similar to a goroutine and channel design. - # - # another nice benefit of this method is that we can timeout the - # IO.select call, allowing the profile to automatically stop after - # a given interval (by default 30 seconds), avoiding unbounded memory - # growth from a profile that was started and never stopped. - t = Thread.new do - timeout_s = ENV['STACKPROF_TIMEOUT_S']&.to_i || DEFAULT_TIMEOUT_SEC - current_timeout_s = nil - loop do - read.getbyte if IO.select([read], nil, nil, current_timeout_s) - - if ::StackProf.running? - stackprof_file_prefix = ENV['STACKPROF_FILE_PREFIX'] || DEFAULT_FILE_PREFIX - stackprof_out_file = "#{stackprof_file_prefix}/stackprof.#{Process.pid}.#{SecureRandom.hex(6)}.profile" - - log_event( - 'stopping profile', - profile_filename: stackprof_out_file, - profile_timeout_s: timeout_s - ) - - ::StackProf.stop - ::StackProf.results(stackprof_out_file) - current_timeout_s = nil - else - mode = ENV['STACKPROF_MODE']&.to_sym || DEFAULT_MODE - interval = ENV['STACKPROF_INTERVAL']&.to_i - interval ||= (mode == :object ? DEFAULT_INTERVAL_EVENTS : DEFAULT_INTERVAL_US) - - log_event( - 'starting profile', - profile_mode: mode, - profile_interval: interval, - profile_timeout: timeout_s - ) - - ::StackProf.start( - mode: mode, - raw: Gitlab::Utils.to_boolean(ENV['STACKPROF_RAW'] || 'true'), - interval: interval - ) - current_timeout_s = timeout_s - end - end - rescue => e - log_event("stackprof failed: #{e}") - end - t.abort_on_exception = true - - # in the case of puma, this will override the existing SIGUSR2 signal handler - # that can be used to trigger a restart. - # - # puma cluster has two types of restarts: - # * SIGUSR1: phased restart - # * SIGUSR2: restart - # - # phased restart is not supported in our configuration, because we use - # preload_app. this means we will always perform a normal restart. - # additionally, phased restart is not supported when sending a SIGUSR2 - # directly to a puma worker (as opposed to the master process). - # - # the result is that the behaviour of SIGUSR1 and SIGUSR2 is identical in - # our configuration, and we can always use a SIGUSR1 to perform a restart. - # - # thus, it is acceptable for us to re-appropriate the SIGUSR2 signal, and - # override the puma behaviour. - # - # see also: - # * https://github.com/puma/puma/blob/master/docs/signals.md#puma-signals - # * https://github.com/phusion/unicorn/blob/master/SIGNALS - # * https://github.com/mperham/sidekiq/wiki/Signals - Signal.trap('SIGUSR2') do - write.write('.') - end - end - - def self.log_event(event, labels = {}) - Gitlab::AppJsonLogger.info({ - event: 'stackprof', - message: event, - pid: Process.pid - }.merge(labels.compact)) - end - end -end - if Gitlab::Utils.to_boolean(ENV['STACKPROF_ENABLED'].to_s) Gitlab::StackProf.install end |