Transparent HugePages Question
Hello,
I have a CentOS 7 installation on baremetal with 2 CPUs, 10 cores each and HT enabled, 128 GB RAM.
The system has transparent hugetables enabled.
cat /sys/kernel/mm/transparent_hugepage/enabled
[always] madvise never
The system reports anonymous hugepages pages usage and a size of hugepage of 2048Kb
cat /proc/meminfo |grep -i hugepages|grep AnonHugePages AnonHugePages: 35491840 kB
cat /proc/meminfo |grep -i hugepages|grep Hugepagesize Hugepagesize: 2048 kB
Anyway, checking the /proc/
for i in `ls /proc/|egrep ‘[0-9]+’` ; do grep ‘KernelPageSize: ‘
/proc/$i/smaps; done|grep ‘ 4 kB’|wc -l
9758
for i in `ls /proc/|egrep ‘[0-9]+’` ; do grep ‘KernelPageSize: ‘
/proc/$i/smaps; done|grep -v ‘ 4 kB’|wc -l
0
So it turns out that even is I have the THP enabled the pages still have a size of 4K .
Is there any extra setup in order to get 2MB pages ?
Thanks, Laurentiu
4 thoughts on - Transparent HugePages Question
Laurentiu Soica wrote:
Be aware that with transparent huge pages enabled – I’m trying to remember what error you might get – it may be the “CPU blocked for x 120 seconds”, as it deals with the page.
mark, back from vacation
So basically you’re saying that this THP feature is broken for CentOS 7 ?
The feature is enabled by default. Is there a thread opened on this issue ?
În mie., 24 aug. 2016 la 18:13, a scris:
Laurentiu Soica
Laurentiu Soica wrote:
I’m not sure it’s broken, per se, but rather that something that I don’t know may cause it to do this. It was certainly the case on 6.
mark
SQL database folks seem to say to turn it off regardless of the OS. I
think the whole thing is broken by design.