Comments on: Linux HugeTLBfs: Improve MySQL Database Application Performance

By: juan

juan — Sun, 02 Aug 2009 16:02:31 +0000

Can i use HugeTLBfs for PostgreSQL?

By: Taylan Develioglu

Taylan Develioglu — Fri, 17 Jul 2009 12:58:52 +0000

nonsense…

have you noticed 68719476736 translates to 65gb?

huge pages are only supported by the innodb engine , and vm.nr_hugepages should be set to match the memory used (i.e. buffer pool size) by it accordingly , not some arbitrary value as you’re suggesting.

And why raise the shared memory limit to 16gb if you’re going to use only 1 gb (512 pages) (8gb is the default in linux 2.6).

your post does not provide any useful information over what is already in the mysql documentation, and by omitting cricital details it is actually harmful. If you’re going to blindly copy+paste existing documentation as if it was new, at least get it right.

The mysql docs are at http://dev.mysql.com/doc/refman/5.1/en/large-page-support.html, for those interested

By: kim jong il

kim jong il — Wed, 27 May 2009 19:16:39 +0000

this was news in 1986 when the ‘386 debuted….

By: wlong

wlong — Fri, 22 May 2009 10:02:00 +0000

I got an Innodb Error message:
[root@andromeda ~]# tail -n 10 /var/log/mysqld.log
090523 01:58:57 mysqld started
InnoDB: HugeTLB: Warning: Failed to allocate 8404992 bytes. errno 12
InnoDB HugeTLB: Warning: Using conventional memory pool
090523 1:58:57 InnoDB: Started; log sequence number 0 43655
Warning: Failed to allocate 8388608 bytes from HugeTLB memory. errno 12
Warning: Using conventional memory pool
090523 1:58:57 [Note] /usr/libexec/mysqld: ready for connections.
Version: ‘5.0.45′ socket: ‘/var/lib/mysql/mysql.sock’ port: 3306 Source distribution

By: Vivek Gite

Vivek Gite — Wed, 20 May 2009 13:03:35 +0000

The FreeBSD virtual memory subsystem now supports fully transparent use of superpages for application memory; application memory pages are dynamically promoted to or demoted from superpages without any modification to application code. This change offers the benefit of large page sizes such as improved virtual memory efficiency and reduced TLB (translation lookaside buffer) misses without downsides like application changes and virtual memory inflexibility. This is disabled by default and can be enabled by setting a loader tunable vm.pmap.pg_ps_enabled to 1. Add vm.pmap.pg_ps_enabled=1 to /boot/loader.conf.

However, I’ve not tested it with MySQL or anything else…

HTH

By: Vladimir Micovic

Vladimir Micovic — Wed, 20 May 2009 12:53:02 +0000

can i try this on fbsd?

By: Vivek Gite

Vivek Gite — Wed, 20 May 2009 09:26:03 +0000

Yes, Ubuntu Linux has different file locations. Thanks for sharing the information.

By: blink4blog

blink4blog — Wed, 20 May 2009 08:52:42 +0000

I am implementing this under Ubuntu 9.0.4 with MySQL 5.0.75-0ubuntu10, few points I would like to clarify:

1. the command of “grep -i huge /proc/meminfo” returns the following:

HugePages_Total: 0
HugePages_Free: 0
HugePages_Rsvd: 0
HugePages_Surp: 0
Hugepagesize: 4096 kB

2. my.cnf should be located under /etc/mysql/my.cnf

3. the command to restart mysql should be # /etc/init.d/mysql restart