New post

#InterSystems Data Platform Blog

11

This group consists of fairly long technical posts regarding InterSystems Technology features and experience.

Every post in this group is a story of a developer or engineer who wants to share his experience related to InterSystems Data Platform with you.

Every post in this group contains either snippets of code or even ready to use projects with sources on Github or with working demos of InterSystems Technology.

Every post is reviewed by InterSystems specialists through a special reviewing procedure.

Subscribe to the group and you'll get weekly posts with essentials of experience on developing, testing, deploying, maintaining solutions that utilize InterSystems Data Platform technology: multimodel DBMS Caché,  Platform for connected applications Ensemble, analytics technology DeepSee and unstructured data management technology  - iKnow.

Yes, you can contribute to this group. If you want to share your experience, promote interesting development tool or a framework to InterSystems Developer Community in the form of a long article reviewed by InterSystems engineers - please contact me.

Evgeny Shvarov,

InterSystems Community Manager

** Revised Feb-12, 2018

While this article is about InterSystems IRIS, it also applies to Caché, Ensemble, and HealthShare distributions.

Introduction

Memory is managed in pages. The default page size is 4KB on Linux systems. Red Hat Enterprise Linux 6, SUSE Linux Enterprise Server 11, and Oracle Linux 6 introduced a method to provide an increased page size in 2MB or 1GB sizes depending on system configuration know as HugePages.

At first HugePages required to be assigned at boot time, and if not managed or calculated appropriately could result in wasted resources. As a result various Linux distributions introduced Transparent HugePages with the 2.6.38 kernel as enabled by default. This was meant as a means to automate creating, managing, and using HugePages. Prior kernel versions may have this feature as well however may not be marked as [always] and potentially set to [madvise].

Transparent Huge Pages (THP) is a Linux memory management system that reduces the overhead of Translation Lookaside Buffer (TLB) lookups on machines with large amounts of memory by using larger memory pages. However in current Linux releases THP can only map individual process heap and stack space.

6 9
5 5K