[erlang-questions] Strange server behavior when high load on erlang node
Mon Jan 30 14:49:05 CET 2012
I see strange server behavior when I apply high load on my erlang node.
My OS is Ubuntu 11.04 64 bit.
I use Erlang/OTP exmpp with xpath.
I have ~3000 processes running. All processes are OTP.
My hardware is:
CPU: 2 x Intel Xeon 5420 Quad Core 2.50 GHz
RAM 16 GB
My sysclt is the following:
* # General gigabit tuning:
* **net.core.rmem_max = 16777216*
* **net.core.wmem_max = 16777216*
* **net.ipv4.tcp_rmem = 10240 87380 16777216*
* **net.ipv4.tcp_wmem = 10240 65536 16777216*
* **net.ipv4.tcp_syncookies = 1*
* **net.ipv4.ip_local_port_range = 10000 65000*
* **kernel.max_pid = 4000000*
* **net.ipv4.tcp_window_scaling = 1*
* **net.ipv4.tcp_timestamps = 1*
* **net.ipv4.tcp_sack = 1*
* **net.ipv4.tcp_no_metrics_save = 1*
* **kernel.sem = 250 32000 100 128*
* **kernel.shmmni = 4096*
* **fs.file-max = 100000*
* **vm.swappiness = 0*
* **vm.vfs_cache_pressure = 50*
* **kernel.msgmax = 665536*
* **kernel.shmmax = 68719476736*
* **kernel.shmall = 4294967296*
Please see the end part of each graph.
This is CPU:
This is IRQ:
This is Interrupts:
This is eth0:
So, my questions about graphs are:
1. Why my IRQ are so high? Especially "Rescheduling interrupts"? I read
somewhere that it could be because of power management and it is expectable
that server consumes more energy under the load, but I have to idea how to
fix it in this case.
2. Why "Interrupts" are so high?
Please, Erlangers, *those of you who has experience with highly loaded
erlang nodes* tell me about your experience:
1. Which values of IRQ and Interrupts are ok/normal?
2. Which values you see on your servers under high load?
3. Which OS is the best for high computation/traffic to host Erlang/OTP
4. Which settings you apply to you OS (general description or configs are
welcome) to manage high load on Erlang?
I hope that this information will be useful for all of us, because I
believe everybody will face problems like I do one day when high load is
Thank you all in advance!
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