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questions about tuning a NUMA server

leguan
New Contributor III

Hello everyone, 

i have some questions about tuning q processes on NUMA server (linux kernel version is above 3.x). 

1. According to https://code.kx.com/q/kb/linux-production/  [1]  it is suggested to disable interleave and enable zone_reclaim, however https://code.kx.com/q/kb/cpu-affinity/#activating-numa [2]  suggests 

a) "numactl --interleave=all --physcpubind=0,1,2 q" 

Q1. Why allows the process to access all node's memory instead of bind the process to local memory only? 

b) "echo 0 > /proc/sys/vm/zone_reclaim_mode"  which lets the process closes zone-reclaim and takes other numa nodes's memory. 

Q2. Is zone_reclaim_mode=1  the correct answer according to [1] ? 

The attached shows one of our q process,  on a numa-enabled server, binds to mem 0-3, 

Q3. Is it identical to "interleave=all" ? 

Q4. If i want this process access local mem only,  shall i execute  "numactl --interleave=0" ?

Q5. following up Q4, How to start a q process and put numactl command's to work in kx-platform?  which Reversed Parameter shall be edited? or, should i "run"/start a process first, then  execute system "numactl --interleave=0 --physcpubind=0 " inside process's console ?

thank you and the best,

leguan, 

leguan_0-1640747957571.png

 

3 REPLIES 3

leades
Moderator Moderator
Moderator

Hello,

Great questions for the Community! I will share them internally and come back with any feedback.

Many thanks

Luke

leguan
New Contributor III

Hello Luke,

May i know if there is any update from tech-team? 

best,

leguan

Hello,

Thank you for your patience.

We have escalated it with the appropriate teams internally and will hopefully get back with an answer soon.

Many Thanks

Luke