Performance Optimization Guide: Difference between revisions

This guide is about performance optimization of the Allegro for specific use cases. By default, the Allegro runs in a configuration that fits for the majority of users and you do not need to change any parameter of the configuration.

The Allegro has various units that processes the traffic. These units are:

* I/O threads: responsible for all I/O operations between the interfaces and cpus

* Analyzer threads: responsible for decoding and most of the database operations

* DB threads: optional threads offloading memory intensive database operations, see [[DB mode]]

The Allegro uses queues to buffer packets and messages between the hardware instances ( interfaces chips, central processing unit, storage ) and threads. All threads measure their which you can monitor at '''Info''' → '''System Info''' → '''Load'''.

The following queues can be monitored to see where you need to change settings in the Allegro:

The interface hardware queue is between the interfaces and I/O threads of the central processing unit. Whenever the I/O threads are too slow to consume all packets from the built-in or extension interfaces, the '''hardware miss''' counter of the interface statistics will increase over time.  

If this counter increases regularly, you can try to use the sink mode and to increase the number of I/O threads.

The bridge mode requires approximately 10 - 30 % more load on the I/O Threads as the sink mode. The I/O threads have to sent the traffic to the corresponding network interface for forwarding.

For configuration, please see: [[Global_settings#Packet_processing_mode]]

 

The number of I/O threads can be increased at the cost of analyzer threads. This option is available on the Allegro 3000 and above as these devices have a high cpu. Allegro recommends to increase the analyzer threads only on the Allegro 1000 and above if necessary.

 

This setting can be changed at '''Settings''' -> '''Global Settings''' → '''Expert Settings'''

 

[[File:Rx sockets io thread.png|600px]]

 

Allegro recommends to test with HT enabled and 2 or 4 threads for I/O. If you disable the load on the analyzers ( see [[#High analyzer load]] ), you can also test with 4 I/O Threads without HT for maximum performance.

The Allegro has a packet queue between I/O threads and the analyzer threads.  Please note that the increasing counters at the initial startup of the Allegro can be normal under high load scenarios for a few seconds. You can check at the '''Interface stats''' per interface all I/O threads could push all packets to the analyzer queues or not. The counter is '''Not processed due to overload'''.