MySQL Forums
Forum List  »  Performance

large-pages variable set but mysql doesn't use huge pages
Posted by: Andres March
Date: February 14, 2008 06:36PM

I hope that this is something I'm simply doing wrong. Running on RHEL4. I have enabled 2GB of Huge Pages and set the large-pages variable but MySQL is not using them. I'm currently loading a large db (> 20GB). Here is some stats:

bash-3.00# cat /proc/meminfo
MemTotal: 7914912 kB
MemFree: 23612 kB
Buffers: 356 kB
Cached: 11800 kB
SwapCached: 4095316 kB
Active: 5758588 kB
Inactive: 12764 kB
HighTotal: 0 kB
HighFree: 0 kB
LowTotal: 7914912 kB
LowFree: 23612 kB
SwapTotal: 16779884 kB
SwapFree: 11352936 kB
Dirty: 0 kB
Writeback: 0 kB
Mapped: 5761552 kB
Slab: 27532 kB
CommitLimit: 19713340 kB
Committed_AS: 8264048 kB
PageTables: 17916 kB
VmallocTotal: 536870911 kB
VmallocUsed: 8956 kB
VmallocChunk: 536861555 kB
HugePages_Total: 1000
HugePages_Free: 1000
Hugepagesize: 2048 kB

Notice no Huge Pages are being used. Now checking the db:

mysql> show variables like '%large%';
| Variable_name | Value |
| large_files_support | ON |
| large_page_size | 2097152 |
| large_pages | ON |
3 rows in set (0.19 sec)

So this doesn't make sense. I also made sure the limits were wide open for the process to grab memory:

bash-3.00# cat /etc/security/limits.conf

mysql soft memlock unlimited
mysql hard memlock unlimited

What am I doing wrong? Check out what the process is using:

Mem: 7914912k total, 7873636k used, 41276k free, 2448k buffers
Swap: 16779884k total, 5516492k used, 11263392k free, 56944k cached

19364 mysql 16 0 25 145:00.93 70.2 8042m 5.3g 2632 S mysqld


Options: ReplyQuote

Sorry, you can't reply to this topic. It has been closed.

Content reproduced on this site is the property of the respective copyright holders. It is not reviewed in advance by Oracle and does not necessarily represent the opinion of Oracle or any other party.