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Telecom Control and Data Plane Convergence
Choosing the right multicore software architecture for
high performance control and data plane applications
Magnus Karlsson
Systems Architect
Telecom Market Conditions
 IP-based services driving
exponential data traffic growth
Traffic volume
Expected
Traffic volume
 High focus on rich user
experience and service
platforms
Expected
Revenue
 Declining Average Revenue
Per User (ARPU)
 Focus on Network OPEX and
CAPEX cost
Desired
network
cost/bit
Time
Voice dominated
Data dominated
Trends in Telecom
 Telecom is going “ALL IP”
- Massive IP packet processing applications
- Power consumption is a critical design factor
- QoS is becoming increasingly important – telecom reliability in the
datacom world
 Industry response:
- Application specific processors, multicore and HW acceleration engines
- CPU and DSP use cases converging
- Integration of control plane and data plane into the same multicore
processors
Fundamental Differences between Control Plane
and Data Plane Applications
 Control Plane Characteristics:
- CPU bound processing
- Operations And Maintenance functions
- Typically terminates IP traffic
 Data Plane Characteristics
- IO bound processing
- Highly optimized to use as few CPU cycles as
possible
- Typically do not terminate IP traffic
Multicore in Networking Applications
Examples
Application Type => Software Architecture
Parallel, symmetric processing
”run-to-completion”
Parallel, asymmetric processing
functional pipelining
egress
ABC
ABC
egress
ABC
ingress





All tasks in a flow can be handled by a thread
I/O bound processing – low cpu budget
Load balancing through hardware support
Scaling depends on advanced HW support
Popular for data plane
C
C
B
B
A
A
ingress





Different cores work on different stages
Complex protocols - CPU bound processing
Load balancing through run-time rebalancing
Scaling capability depends on OS support for
state migration/sharing
Popular for control plane and O&M
Application Type => Software Architecture
Parallel, symmetric processing
”run-to-completion”
Parallel, asymmetric processing
functional pipelining
egress
ABC
ABC
egress
ABC
ingress





All tasks in a flow can be handled by a thread
I/O bound processing – low cpu budget
Load balancing through hardware support
Scaling depends on advanced HW support
Popular for data plane
C
C
B
B
A
A
ingress





Different cores work on different stages
Complex protocols - CPU bound processing
Load balancing through run-time rebalancing
Scaling capability depends on OS support for
state migration/sharing
Popular for control plane and O&M
Another view of Multi-core Use Cases
IP Packet Processing
Control Plane
CPU-bound
Cycles/Byte
SMP domain
Linux or
RTOS
Termination
Control
Signaling
IO-bound
Transcoding
AMP Linux,
RTOS or
”bare-metal”
domain
Deep Packet Inspection
Intrusion Prevention
Other
IP
Forwarding
Data Plane
Level of parallelism
or cores
Multiple Use Cases Demand Multiple OS Solutions
One “size” doesn’t fit all – i.e. both Linux and RTOS
Requirements on Multicore Operating
Systems
 Future for data plane applications
Bare-metal or AMP
 Direction for control plane apps
SMP
Challenge:
Find an operating environment for multicore processors that satisfy both data
plane and control plane applications, despite their fundamental differences.
Solution:
Use a modular and flexible system that combines the best characteristics of
SMP, AMP and bare-metal.
Incumbent Configuration for Integrated
Control and Data Plane
SMP Operating System + Bare-Metal
Control plane application
Shared OS resources
SMP OS
Core 0
Core 1
Data plane app
Exec. env
Core 2
…
Data plane app
Exec. env
Core n
Advantages:
• Control plane application can use high-level SMP RTOS or Linux
• Can fully utilize processor vendor’s Executive Environment, if any
• Raw bare-metal performance for data plane processing
Disadvantages:
• Bare-metal cores becomes silos, hence only suitable for run-to-completion applications
• Poor debugging, profiling and run-time management capabilities on bare-metal cores
• No platform services available such as IPC, file systems and networking stacks on bare-metal
cores
Introducing “XMP” – A better Way
XMP provides both SMP and AMP Characteristics
XMP Hybrid AMP/SMP Multiprocessing
Common shared OS resources
Scheduler
Scheduler
…
Scheduler
…
Core n
Kernel event backplane
Core 1
Core 2
SMP Characteristics:
AMP Characteristics
• Easy to use
• Simple configuration
• Load balancing/process migration
• Deterministic
• Very good scalability
• Suitable for IO intensive applications
XMP – Combining the Best of AMP and SMP in One RTOS
Enea OSE Multicore Edition – an XMP Solution
 Linear scalability of performance on multicore devices
- Asymmetric kernel design that has a scheduler instance on each core
- Avoid use of global or shared locks in kernel calls or interrupt processing
 Maintain single core performance on each core
- Enhanced driver execution model, allows HW vendor bare-metal SDK:s “Executive
Environments” to run inside an OSE process without additional overhead
 Management and debug
-
Shared OS services as in an SMP OS
Seamless runtime debugging, CPU and memory profiling on all cores
User defined load-balancing based on open API
Booting, loading, starting and stopping applications
Fault management
OSE 5 / Multicore Edition
Fully featured RTOS for distributed and fault-tolerant systems

Highly Scalable RTOS

Designed for distributed systems

Support for memory protection
and dynamic software updates

Comprehensive IP networking
support

Optima tools integrated with
CodeWarrior

Multicore Edition:

Hybrid SMP/AMP Microkernel

SMP ease-of-use/configuration

AMP scalability and performance

Ability to run bare-metal
applications on a core
Reaching Bare-Metal Performance
 Supervisor threads + polling busy loop to achieve bare-metal performance
 The rest of the OS functionality can be used as needed
- No OS overhead when not in use
 Provides management, debugging and profiling of software on all cores
Bare-Metal Performance and Linear
Scalability in OSE Multicore Edition
 “Bare Metal” Light-Weight Executive - packet polling loop
 Enea OSE Multicore Edition version 5.4.1
 Two benchmark scenarios:
- Packet processing
- Simple packet routing in a bare-metal environment
- Simple packet routing in an OSE Multicore Edition process, with full access to all
services in OSE
- Scalability
- Instantiation of a “silo” application over many cores
Throughput Mbyte/s
Data Plane Processing Performance
Bare-Metal
OSE ME
112
128
256
512
1025
1280
1518
Frame size
 Performance nearly identical to raw bare-metal speed
Scalability over many Cores
Total number of transactions (normalized)
Scalability OSE Multicore Edition vs Linux
18
16
14
12
10
OSE
8
Ideal
6
4
2
0
1
2
3
4
5
6
7
8
9
10
Number of cores
11
12
13
14
15
16
What about Linux for Control Plane and OSE
Multicore Edition for Data Plane?

Who owns the boot and configuration policies?

How to partition shared resources like memory?

How to share devices and services in runtime?

How to be able to profile and debug all parts of the system?

How to be able to dynamically balance the load?
Challenge:
How do we create hardware abstraction for all those OS:es? A classic
request, but historically put on OS by applications!
Solution:
Heterogeneous execution environments on multicore devices needs a new
“OS” software layer, a so called Hypervisor!
Enea Hypervisor
Example: Linux, RTOS & EE Applications
Multicore Processor
Linux App
RTOS/App
Tools and
Management I/F
EE App
Linux
Enea Hypervisor
CPU 0
CPU 1
CPU 2
 Based on OSE Multicore Edition technology: flexible, lightweight, extensible, framework
for execution and management
 Enables multiple operating environments to coexist on the same multicore in different
configurations
 Enables boot, remote management and system configuration control
 Enables tool support for debugging and profiling of the whole system
Enea Hypervisor Features
 Provides support to:
- Dynamically load and remove native applications, or
guest domains
Multicore Processor
- Measure CPU load per core or individual application
in runtime
- Define scheduling policy between guest domains
Linux App
RTOS/App
- Perform system wide load regulation
- Communicate between guest domains using Enea
LINX
Bare Metal
Linux
Enea Hypervisor
CPU 0
CPU 1
- Share services like file systems across guest
domains
Optimized for co-existence between Linux and OSE
– LINX communication channel over shared memory
– Shared file system using LINX
– Shared Ethernet device(s)
– Shared console
CPU 2
Low Entry Alternative
A lightweight OS model for Control/Data Plane
OSEck for Multicore CPU’s – AMP Model
OSEck – Enea “lightweight” kernel executive
Background
User App /
System Proc
Foreground
User App
Executive Env.
OSEck
Worker
Core X
Ethernet
Data Plane
LINX over
Shared
Pools

LINX shared pool connection manager

Implements support for EE applications

Optima support

Bare-metal performance

Easy migration - simple to port user applications

Add observability on a per core level

Linux Management Core
Worker
Core Y
LINX over
Shared
Pools
Linux
Management
Core
LINX over
Ethernet
OSEck – Two Scheduling Models
Pre-emptive Model
CPU x
Optima
Monitor
IDLE
dSPEED
dSPEED
dSPEED
Interrupt-driven
Run-to-completion Model
CPU y
Optima
Monitor
dSPEED
dSPEED
dSPEED
IDLE
PRI
0-31
PRI
0-31
LINX
RLNH
Shell
LINX
RLNH
Shell
Timeout
Server
Timer
INT
0-31
LINX
Shmem
RX
Timeout
Server
Timer
Run-to-completion
processing loop
LINX
Shmem
RX
INT
1-31
INT0
Scalable, Uniform IPC – Enea LINX
Core-to-core, device-to-device, board-to-board level message based IPC

Intra-core communication (OSE and OSEck)
- Intra-core message passing is by reference (zero-copy)

Inter-core communication (LINX)
- LINX can transport messages over shared memory, DMA,
hardware queues etc.

Message
Process 1
Inter-device communication (LINX)
- Accomplished using LINX communicating over
sRIO, Ethernet or PCIe
Process 2

Open source for Linux, superior in performance to TIPC

Proprietary for OSE, OSEck and other OS
OSEck for MSC8155/56
 Message ID
 Sender
 Receiver
 Owner
 Data
PC
OSE for P4080
LINX over Shared Memory / sRIO / Ethernet / …
SC3850 SC3850 SC3850 SC3850 SC3850 SC3850
Control
Worker
Worker
e500
e500
e500
GPP
Process 3
Enea Multicore Solutions





Target Customers:
Network Equipment Providers
Adjacent markets
Target applications:
Packet forwarding/processing
LTE L1/L2 processing
Connectivity layer processing
Combined Control/Data plane
Cycles/Byte



Transcoding
Termination
Other
Packet
Processing
Control
Signaling
IP
Forwarding
Level of parallelism






Enea Offering:
OSE ME - Fully featured Multicore RTOS with SMP ease-of-use and AMP performance/scalability
Enea Hypervisor – for heterogenous/guest OS support, like Linux + OSE
OSEck - Compact Kernel “AMP” RTOS for signal processing/packet processing on multicore CPU’s/DSPs
LINX - Inter Process Communication (IPC) framework: OS, processor, interconnect independent
Optima – Eclispe Development tools for debugging and system profiling/analysis
True Convergence of Control and Data Plane
A single implementation that supports SMP
and AMP, or Hybrid models for All Use
Cases:
• Control Plane
• Control + Data Plane (with bare metal)
• Data Plane
Technologies and features
• Heterogeneous systems - support for
both Linux and RTOS
• Hypervisor/Virtualization
• Performance
• Load balancing
• Fast Path IP
• System wide IPC
• High Availability – Fault Localization
• Integration with applications
environments
• Eclipse based Integrated tools
Summary
No “one” processing model meets every use case for multicore in
telecom. An understanding of specific use cases is crucial in
determining the best solution:
 Control plane and data plane applications require different software
architectures, but can co-exist on multicore processors
 A flexible OS platform that can combine properties of bare-metal, AMP, and
SMP is the best fit
Enea provides the most flexible OS framework that addresses most
use cases
 OSE Multicore Edition with its hybrid kernel technology can support both IO
and CPU bound processing in one homogeneous configuration
 For control plane applications on Linux, OSE Multicore Edition can be
extended with Hypervisor support to incorporate guest domains in a
heterogeneous configuration
 OR, a lightweight, small footprint AMP model for special low end or entry use
cases
Questions?
[email protected]