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Need help optimising debian for single thread applications
ECNetworks
Member
in Help
I need to reduce overhead in debian. The system specifications cannot be the problem for I have the (current) best processor for single thread performance (I7-4790K) in this dedicated server. 32GB DDR3 2600MHz (overclocked) ram and it still lags like a dying duck.
Anyone willing to offer a hand with reducing the lag on this thing? It's on SSDs to. I have optimised /etc/fstab.
Comments
What are you defining as "overhead". That is, what metric are you looking at?
I don't have a clue what you just said. It's a single core application and I need to reduce the resources that debian is using. I need to optimize RAM and CPU configuration as those are the resources my application is slaughtering.
Oh metric I see, CPU and RAM usage. I/O usage and basically all round system overhead. ANY SLIGHT OPTIMISATIONS XD
I refuse to think that a forum FULL of people talking about linux does not know how to optimise a system.
I would assume it's game server?
If so, i can build the kernel specially for the needed game/application. Also some low-level system tweaks will help. I worked with game hostings for this job, especially hlds and srcds engines. BTW it's not the best for single core application. It's good that it's rather fresh, but MHz is important here. I would recommend looking for something like Intel® Xeon® Processor E5-1660 v2 with enabled turboboost and disabled HyperThreading.
We may not care, or you haven't give uw clues. What virtualization?
Don't use virtualization. I hate VPS. I only use hard based systems @netomx
@profforg Yes, it's a gameserver, tekkit classic to say the least and it eats the I7-4790k for lunch.
http://cpubenchmark.net/singleThread.html
What kind of lag do you have?
It comes in spikes every now and again. Normally around 25-60 players the server starts experiencing unstable tick. Normally going down to 19.6 TPS for a couple of seconds. the most it can run at is 20. Sometimes it can go horribly down to 8 TPS due to the quantum killers i keep finding, but it drives me insane having to gather my staff together to deal with 18 TPS.
I am using hugepages and vm.swappiness is NOT DISABLED and is at it's default value.
Disable swappiness? With that ram, you don't need it
So /etc/sysctl.conf set vm.swappiness= 0?
Alright. 2 seconds.
root@deatrix:~# sysctl -p
net.ipv4.tcp_fin_timeout = 5
net.ipv6.conf.all.autoconf = 0
net.ipv6.conf.default.autoconf = 0
net.ipv6.conf.eth0.autoconf = 0
net.ipv6.conf.all.accept_ra = 0
net.ipv6.conf.default.accept_ra = 0
net.ipv6.conf.eth0.accept_ra = 0
vm.nr_hugepages = 4096
vm.swappiness = 0
@netomx swap is completely disabled now. I don't see any major system performance increases since I don't think it was using swap anyways.
I'm looking for more RAM/CPU/I.O optimizations like /etc/fstab and processor forcing. My processor is forced to it's non turboboost speed of 4GHz but will not go to 4.4GHz (turboboost) and I don't know how to enable it. I use cpufreq to control CPU frequency.
You can't do much more than disabling EIST/Speedstep to force full speed of the CPU - There are no real triggers/settings for CPU performance inside the kernel.
It's running at 4001MHz on ALL CORES right now, although i would like it locked to its full turbo boost speed.
@William I suppose it murders the processor to be running at more then it's max TDP. But I don't really care, the people I colocate with have replaced the last two blown out I7s that I threw off. For free.
Is acpi_freq module loaded in your kernel? What kernel version are you running?
Sec
How do I check if acpi_freq module is loaded?
Kernel version:
Linux deatrix.org 3.2.0-4-amd64 #1 SMP Debian 3.2.65-1+deb7u1 x86_64 GNU/Linux
Also try looking at this tool. Might be of help.
https://code.google.com/p/i7z/
Tried that tool. Didn't throw any errors, said my processor was unsupported.
If you only care about one process running one thread on one core you can disable the other cores from the BIOS and leave only one core enabled and also disable hyperthreading. This will help the single core to be able to run at maximum speed without overheating the whole CPU and without going in thermal throttling.
Of course if there are multiple processes competing for the CPU this won't work.
Of course there are, such as the OS, MySQL, php etc. for I have to run a web based control panel for my staff to use.
I need them other cores enabled. And I use hyperthreading. Plus I can't access the BIOS my collocated machine does not have a KVM.
This wasn't your gaming PC?
No. My Gaming PC has an I7-5960X. The dedi im talking about has an I7-4790K. My gaming PC is fine, I'm talking about debian running on a SERVER. @netomx
something like : lsmod | grep acpi should do the trick.
Edit: Also, I'm curious. You've made a reference to "my staff" a few times already. What staff are you referring to? You have "staff" but don't know how to list loaded modules, didn't know what CLI stood for, and you're asking about basic system performance tweaking?
Yeeees, By staff I mean the developers of ECNetworks. They have a panel. Nothing more. And by CLI i tend to say SSH or headless instead.
You want meaningful advice? Then give us meaningful info.