From: Brice Figureau <[email protected]> Each time the compiler was accessing the loaded types, we were checking if the manifests had changed. This incurred a large performance cost compared to 0.25 and introduced race conditions if manifests changed while a thread was in the middle of a compilation.
This tentative fix, based on Brice's, makes sure each thread will get access to the same loaded types collection for the durration of a compilation, even if the manifests change. We now only check for changed files at the start of a compilation or if the environment changes, and we maintain a per environment thread lock so that only one thread at a time can be reloading any particular environment (and the need-check is done inside the synchronize block so that only the first will actually load it). As long as the manifests don't change, the threads will share the same collection, so there is only duplication in memory for a brief window surrounding a change. Signed-off-by: Brice Figureau <[email protected]> Second-author: Markus Roberts <[email protected]> Signed-off-by: Markus Roberts <[email protected]> --- lib/puppet/node/environment.rb | 20 +++++++++++++++----- lib/puppet/parser/compiler.rb | 5 +++++ spec/unit/node/environment_spec.rb | 35 ++++++++++++++++++++++++++++++++--- 3 files changed, 52 insertions(+), 8 deletions(-) diff --git a/lib/puppet/node/environment.rb b/lib/puppet/node/environment.rb index 762599c..3f67474 100644 --- a/lib/puppet/node/environment.rb +++ b/lib/puppet/node/environment.rb @@ -1,4 +1,5 @@ require 'puppet/util/cacher' +require 'monitor' # Just define it, so this class has fewer load dependencies. class Puppet::Node @@ -67,14 +68,23 @@ class Puppet::Node::Environment def initialize(name) @name = name + extend MonitorMixin end def known_resource_types - if @known_resource_types.nil? or @known_resource_types.stale? - @known_resource_types = Puppet::Resource::TypeCollection.new(self) - @known_resource_types.perform_initial_import - end - @known_resource_types + # This makes use of short circuit evaluation to get the right thread-safe + # per environment semantics with an efficient most common cases; we almost + # always just return our thread's known-resource types. Only at the start + # of a compilation (after our thread var has been set to nil) or when the + # environment has changed do we delve deeper. + Thread.current[:known_resource_types] = nil if (krt = Thread.current[:known_resource_types]) && krt.environment != self + Thread.current[:known_resource_types] ||= synchronize { + if @known_resource_types.nil? or @known_resource_types.stale? + @known_resource_types = Puppet::Resource::TypeCollection.new(self) + @known_resource_types.perform_initial_import + end + @known_resource_types + } end def module(name) diff --git a/lib/puppet/parser/compiler.rb b/lib/puppet/parser/compiler.rb index a901c0d..760d5a7 100644 --- a/lib/puppet/parser/compiler.rb +++ b/lib/puppet/parser/compiler.rb @@ -15,6 +15,11 @@ class Puppet::Parser::Compiler include Puppet::Resource::TypeCollectionHelper def self.compile(node) + # At the start of a new compile we don't assume anything about + # known_resouce_types; we'll get these from the environment and + # cache them in a thread variable for the duration of the + # compilation. + Thread.current[:known_resource_types] = nil new(node).compile.to_resource rescue => detail puts detail.backtrace if Puppet[:trace] diff --git a/spec/unit/node/environment_spec.rb b/spec/unit/node/environment_spec.rb index b400865..6edcce5 100755 --- a/spec/unit/node/environment_spec.rb +++ b/spec/unit/node/environment_spec.rb @@ -53,6 +53,7 @@ describe Puppet::Node::Environment do @env = Puppet::Node::Environment.new("dev") @collection = Puppet::Resource::TypeCollection.new(@env) @collection.stubs(:perform_initial_import) + Thread.current[:known_resource_types] = nil end it "should create a resource type collection if none exists" do @@ -71,13 +72,41 @@ describe Puppet::Node::Environment do @env.known_resource_types end - it "should create and return a new collection rather than returning a stale collection" do - @env.known_resource_types.expects(:stale?).returns true + it "should return the same collection even if stale if it's the same thread" do + Puppet::Resource::TypeCollection.stubs(:new).returns @collection + @env.known_resource_types.stubs(:stale?).returns true - Puppet::Resource::TypeCollection.expects(:new).returns @collection + @env.known_resource_types.should equal(@collection) + end + + it "should return the current thread associated collection if there is one" do + Thread.current[:known_resource_types] = @collection @env.known_resource_types.should equal(@collection) end + + it "should give to all threads the same collection if it didn't change" do + Puppet::Resource::TypeCollection.expects(:new).with(@env).returns @collection + @env.known_resource_types + + t = Thread.new { + @env.known_resource_types.should equal(@collection) + } + t.join + end + + it "should give to new threads a new collection if it isn't stale" do + Puppet::Resource::TypeCollection.expects(:new).with(@env).returns @collection + @env.known_resource_types.expects(:stale?).returns(true) + + Puppet::Resource::TypeCollection.expects(:new).returns @collection + + t = Thread.new { + @env.known_resource_types.should equal(@collection) + } + t.join + end + end [:modulepath, :manifestdir].each do |setting| -- 1.6.4 -- You received this message because you are subscribed to the Google Groups "Puppet Developers" group. 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