Red Hat Bugzilla – Bug 463279
[LTC 6.0 FEAT] 201200:16GB huge pages for POWER
Last modified: 2010-05-06 11:53:52 EDT
Emily J. Ratliff <firstname.lastname@example.org> - 2008-09-16 18:24 EDT
1. Feature Overview:
Feature Id: 
a. Name of Feature: 16GB huge pages for POWER
b. Feature Description
The ability to support a page size of 16GB
2. Feature Details:
Sponsor: PPC - P
Arch Specificity: Both
Affects Core Kernel: Yes
Delivery Mechanism: Direct from community
Request Type: Driver - Feature from IBM
d. Upstream Acceptance: Accepted
Sponsor Priority 2
f. Severity: Medium
IBM Confidential: no
Code Contribution: IBM code
g. Component Version Target: 2.6.27
Performance Assistance: yes
3. Business Case
Using 16GB pages can increase performance for systems running workloads that consume very large
amounts of memory. The target market to leverage 16GB pages includes HPC and large database
workloads. The extent of the performance increase is workload-dependent but typically 5% performance
improvements are seen when moving from 64KB pages to 16MB pages for databases. A smaller increase is
expected for 16GB pages in database applications.
For the specialized HPC system space, selected large government bids have levied the requirement for
massive amounts of dedicated memory on dedicated single-use systems. The ability to specify and
dedicate 16GB pages provides support for these highly specialized applications. The applications
and bids are often high visibility projects for the company. In general, most HPC customers will not
require 16GB pages.
4. Primary contact at Red Hat:
5. Primary contacts at Partner:
Project Management Contact:
Michael Hohnbaum, email@example.com, 503-578-5486
Paul Mackerras, firstname.lastname@example.org
Is this code actually in 2.6.27?
(In reply to comment #4)
> ------- Comment From email@example.com 2008-10-01 16:51:55 EDT-------
> Is this code actually in 2.6.27?
The actual definition of 16G pages is in
There are other supporting patches too; as examples:
There are some bug fixes coming in 2.6.28 related to this feature, but the core code though is in 2.6.27
Since it's in 2.6.27, and RHEL 6 will include a recent upstream kernel, setting to MODIFIED.
The feature requested has already been accepted into the upstream code base
planned for the next major release of Red Hat Enterprise Linux.
When the next milestone release of Red Hat Enterprise Linux 6 is available,
please verify that the feature requested is present and functioning as
this is in 2.6.27
sha1 id: 91224346aa8c1cdaa660300a98e0b074a3a95030
Closing - included in Red Hat Enterprise Linux 6.
------- Comment From firstname.lastname@example.org 2010-05-06 11:47 EDT-------
Verified with RHEL 6 Snap 1.