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Quantification

This page describes LINC's resources consumption.

Adding resources

To add ports and logical switches to the LINC instance you have to edit rel/files/sys.config file. You will there comments on how to do this.

Memory consumptions

LINC has three major components that make up memory consumption:

  • ports and logical switches,
  • flow entries.

Average values

On average a LINC port consumes ~ 11 kb. Memory consumed by logical switches is not linear. For example a logical switch with 20 ports consumes:

  • ~ 1200 kb if we have 10 such switches
  • ~ 2200 kb if we have 20 such switches
  • ~ 5100 kb if we have 30 such switches

Measuring

There is a script scripts/mem_usage_test that helps with estimating memory requirements.

To measure how much memory one port will take use it as follows:

./scripts/mem_usage_test ports <interval> <max_ports_number>

In the test amount of ports indicated by the interval will be added to the LINC instance in each iteration until reaching the max_port_number. The script produces output file ports.test that has three columns:

  • number of ports in the LINC instance,
  • memory consumed by the LINC instance,
  • memory consumed by this LINC instance minus the amount of memory consumed in the previous test. At the bottom of the file there's a summary line.

To memory how much memory one logical switch witch fixed number of ports invoke the script as follows:

./scripts/mem_usage_test switches <ports_per_switch> <max_switches>

In this test an additional logical switch will be added to the LINC instance in each iteration until reaching the max_switches. The test produces an output file that has three columns:

  • number of logical switches started in a LINC instance,
  • memory consumed by the LINC instance,
  • memory consumed by this LINC instance minus the amount of memory consumed in the previous test. At the bottom of the file there's a summary line.

Tuning Erlang VM

Each logical switch allocates approximately 280 ETS tables. To change this value you have to edit rel/files/vm.args file and change the value of ERL_MAX_ETS_TABLES. You find details in the file.

TODO

Measure flow entries.