Bug 446490

Summary:	app-emulation/qemu - transparent hugepage support via madvise (backport request)
Product:	Gentoo Linux	Reporter:	RumpletonBongworth <kfm>
Component:	Current packages	Assignee:	Doug Goldstein (RETIRED) <cardoe>
Status:	RESOLVED FIXED
Severity:	enhancement	CC:	bug, merlin, prometheanfire
Priority:	Normal
Version:	unspecified
Hardware:	All
OS:	Linux
URL:	http://git.qemu.org/?p=qemu.git;a=commitdiff;h=ad0b5321f1f797274603ebbe20108b0750baee94
Whiteboard:
Package list:		Runtime testing required:	---

Description RumpletonBongworth 2012-12-08 15:58:57 UTC

On some platforms, transparent huge page support can be advantageous to KVM performance:

http://www.linux-kvm.org/wiki/images/9/9e/2010-forum-thp.pdf

Currently, the only way to have qemu benefit is to unconditionally enable THP support on the host with the 'always' policy but there are valid reasons not to want to do that. A better approach is to have the application itself use madvise(2) to to enable huge page support for any allocated memory regions as appropriate.

This support has finally made its way into qemu as of commit ad0b532 (a one-liner patch). If there are any plans to stabilize >=qemu-1.2 in the near future, I would really appreciate it if this patch were to be considered for inclusion.

Comment 1 Doug Goldstein (RETIRED) gentoo-dev

2013-01-12 03:55:12 UTC

This is in qemu-1.2.2