How do I improve Momentum performance:

  1. Try increasing the following sysctl parameters to double the existing values. You can try increasing that gradually to 3 or 4 times the current values. Make sure to monitor the CPU and the memory usage on the instance. The current settings can be viewed by running sysctl -a. The idea is to have the net.core.rmem_default and net.core.wmem_default values equal to maximum values i.e. net.core.rmem_max and net.core.wmem_max.
  1. Configure the following in the global scope of the config file: match_cache_size = 2048 This option determines the maximum number of elements in a cache that holds the results of looking up matching scopes. It applies to regex domains, Peer scopes in listeners, and any user-defined scopes that use matching. For more info, please refer:

  2. Include these settings in the configuration file in the scriptlet section to enable lua garbage collection:

scriptlet "scriptlet" { of scriptlet config here...
gc_stepmul = 300
reap_interval = 13
global_trace_interval = 13
gc_trace_thresh = 1200
gc_trace_xref_thresh = 1200
use_reusable_thread = true
max_uses_per_thread = 5000
gc_threadpool = "gc"
gc_step_on_recycle = true
gc_every = 20
ThreadPool "gc" {
concurrency = 10
  1. The event_loops can be tuned in the configuration (this applies only if you have supercharger feature on their license). A sample configuration looks like:
EventLoop "lpool" {  
  concurrency = 6
EventLoop "dpool" {
  concurrency = 6
EventLoop "mpool" {
  concurrency = 6

NOTE: DO NOT go beyond the 75% thread pool allocation rule as mentioned here: One other important setting to try on the customer's end is to tear down and re-establish the injection connections after some time, or set "Max_Receptions_Per_Connection" and "idle_time" in the "esmtp_listener" to avoid a listener connection stay up for long time. This would also cause issues with lua GC.

As always, please monitor the CPU and memory usage. Use the summary command at the /opt/msys/ecelerity/bin/ec_console to verify the current stats. Make sure you run the command "summary reset" at the ec_console to reset the stats before running the script.