© 2019 Apex.AI, Inc. Safe and certified software for autonomous mobility TM Practical memory pool based allocators for Modern C++ by Misha Shalem misha.shalem@apex.ai © 2020 Apex.AI, Inc.● CppCon shall only be allocated and deallocated during non-realtime program phases © 2020 Apex.AI, Inc.Memory pool ● Memory pools with fixed block sizes is a solution which addresses these issues: ○ It provides modifications but allocate from a memory pool under the hood © 2020 Apex.AI, Inc.Implementation Components: 1. A memory pool 2. An allocator which allocates from a memory pool 3. A way to generate bucket definitions

classes must inherit from cms.plugin_base.CMSPluginBase and must register themselves with the plugin_pool. A reasonable convention for plugin naming is: PollPluginModel: the model class PollPluginPublisher: CMSPluginBase from cms.plugin_pool import plugin_pool from polls_cms_integration.models import PollPluginModel from django.utils.translation import gettext as _ @plugin_pool.register_plugin # register patterns directly, for instance: from cms.app_base import CMSApp from cms.apphook_pool import apphook_pool @apphook_pool.register # register the application class PollsApphook(CMSApp): app_name =

CMSPluginBase from cms.plugin_pool import plugin_pool from polls_cms_integration.models import PollPluginModel from django.utils.translation import gettext as _ @plugin_pool.register_plugin # register classes must inherit from cms.plugin_base.CMSPluginBase and must register themselves with the plugin_pool. A reasonable convention for plugin naming is: PollPluginModel: the model class PollPluginPublisher: for a django CMS application: from cms.app_base import CMSApp from cms.apphook_pool import apphook_pool @apphook_pool.register # register the application class PollsApphook(CMSApp): app_name =

CMSPluginBase from cms.plugin_pool import plugin_pool from polls_cms_integration.models import PollPluginModel from django.utils.translation import gettext as _ @plugin_pool.register_plugin # register the classes must inherit from cms.plugin_base.CMSPluginBase and must register themselves with the plugin_pool. A reasonable convention for plugin naming is: • PollPluginModel: the model class • PollPluginPublisher: apphook for a django CMS application: from cms.app_base import CMSApp from cms.apphook_pool import apphook_pool @apphook_pool.register # register the application class PollsApphook(CMSApp): app_name = "polls"

CMSPluginBase from cms.plugin_pool import plugin_pool from polls_cms_integration.models import PollPluginModel from django.utils.translation import gettext as _ @plugin_pool.register_plugin # register the classes must inherit from cms.plugin_base.CMSPluginBase and must register themselves with the plugin_pool. A reasonable convention for plugin naming is: • PollPluginModel: the model class • PollPluginPublisher: apphook for a django CMS application: from cms.app_base import CMSApp from cms.apphook_pool import apphook_pool @apphook_pool.register # register the application class PollsApphook(CMSApp): app_name = "polls"

CMSPluginBase from cms.plugin_pool import plugin_pool from polls_cms_integration.models import PollPluginModel from django.utils.translation import gettext as _ @plugin_pool.register_plugin # register classes must inherit from cms.plugin_base.CMSPluginBase and must register themselves with the plugin_pool. A reasonable convention for plugin naming is: PollPluginModel: the model class PollPluginPublisher: for a django CMS application: from cms.app_base import CMSApp from cms.apphook_pool import apphook_pool @apphook_pool.register # register the application class PollsApphook(CMSApp): app_name =

attempt FixedMemoryPool pool(initSize); try { preSolveWork(); for_each(execution::par_unseq, begin(subdoms), end(subdoms), [&] (auto&& subdomain) { solve(subdomain, pool); }); postSolveWork(); attempt FixedMemoryPool pool(initSize); try { preSolveWork(); for_each(execution::par_unseq, begin(subdoms), end(subdoms), [&] (auto&& subdomain) { solve(subdomain, pool); }); postSolveWork(); Fixed-size memory pool to speed up allocation in parallel loop • Replace for loop with C++17 parallel algorithmParallel domain decomposition Must distinguish 2 errors • Memory pool too small? – Count

for each event handler Pass data to a dedicated background thread Submit tasks to a generic thread pool Submit tasks to a special purpose executorSpawning new threads There are lots of ways to spawn new ideal fit, an alternative is a pool of threadsThread pools If a dedicated processing thread isn’t the ideal fit, an alternative is a pool of threads 1 The thread pool is createdThread pools If a dedicated alternative is a pool of threads 1 The thread pool is created 2 The event handler receives an eventThread pools If a dedicated processing thread isn’t the ideal fit, an alternative is a pool of threads

write the following plugin class: from cms.plugin_base import CMSPluginBase from cms.plugin_pool import plugin_pool from polls_plugin.models import PollPlugin from django.utils.translation import ugettext plugin_pool.register_plugin(CMSPollPlugin) # register the plugin Note: All plugin classes must inherit from cms.plugin_base.CMSPluginBase and must register them- selves with the cms.plugin_pool.plugin_pool plugin_pool. The convention for plugin naming is as follows: • SomePlugin: the model class • CMSSomePlugin: the plugin class You don’t need to follow this, but it’s a sensible thing to do. The template The render_template

classes must inherit from cms.plugin_base.CMSPluginBase and must register themselves with the plugin_pool. A reasonable convention for plugin naming is: PollPluginModel: the model class PollPluginPublisher: CMSPluginBase from cms.plugin_pool import plugin_pool from polls_cms_integration.models import PollPluginModel from django.utils.translation import gettext as _ @plugin_pool.register_plugin # register patterns directly, for instance: from cms.app_base import CMSApp from cms.apphook_pool import apphook_pool @apphook_pool.register # register the application class PollsApphook(CMSApp): app_name =